Proposal summaries
B789 - Do early life experiences influence the development of myopia in adolescents Analysis of data from the ALSPAC cohort - 10/02/2009
People who are short sighted (myopic) have blurred vision for distant viewing, but clear vision for near, and this occurs because their eyes grew too long during childhood and early adolescence. Myopia is becoming more common, and can lead to loss of vision in middle and from degenerative and other changes. Studies show that "nature and nuture" are both important in the development of myopia and the "epidemic" of myopia in Asian children is attributed to as yet little understand factors associated with urban living. As it is becoming increasingly realized that what happens to individuals early in life, indeed, even before they are born, can influence later disease risk, we plan to analyse data collected from a cohort of children when they were aged 15 years who have been followed up regularly since they were born. To our knowledge this will be the first study of myopia during children to use the "life course" approach to analysis although data from the 1958 birth cohort (who are now middle aged) is ongoing, providing a very useful comparative study.
Background: The World Health Organization (WHO) estimate that 153 million people worldwide are visually impaired from uncorrected refractive error, 8 million of whom are blind. The report suggests that 12 million school-age children (5-15 years) are visually impaired from uncorrected refractive errors, and population based surveys undertaken using standard methods and techniques suggest that 90-95% of visual impairment in this age group is due to myopia. Uncorrected myopia is, therefore, a major public health problem.
The following 4 components of the eye determine its refractive status: axial length (AL), corneal curvature, anterior chamber depth, and the thickness, curvatures and internal refractive indices of the lens. After birth the eyes grow in all dimensions, increasing almost threefold in volume by the time adult size is reached. Eye growth is exquisitely controlled so that in most people the AL of the eye increases in tandem with changes in corneal curvature and dimensions of the lens so that the image of distant objects remains focused on the retina. Evidence from laboratory, animal and clinical studies suggests that growth of the cornea and lens are largely controlled genetically whereas AL is influenced at least in part, by visual stimuli. How the visual system detects and adapts to blur, and how this is then translated into altered growth is not known. However it is known that emmetropisation is an active and dynamic process which persists throughout childhood and adolescence, involving an image-processing feedback mechanism in the retina which ultimately influences growth of the sclera. Failure or perturbation of emmetropization can give rise to myopia. The plasticity of this process has been demonstrated in animal experiments in which eye growth has been manipulated by lid closure, diffusers and plus or minus lenses but there is considerable species variation. It seems reasonable, therefore, that changes in the environment in children may also modify eye growth.
There is compelling evidence from twin, family and association studies, and epidemiological research that myopia is a complex disease. However, the rapidly increasing incidence in SE Asia can only be explained by exposure to environmental risk factors that are new or where exposure at the population level is greater and/or more intense. Changes in behaviour and life style consequent to urbanization have been implicated but there are controversies surrounding which elements in childrens' environments are the more important. To date all studies have been either cross sectional or relatively short-term longitudinal studies in which standard multivariate statistical methods have been used. The latter cannot take account of the sequence and timing of the different exposures which are likely to be critical in the development of myopia.
The ALSPAC birth cohort enrolled 14,000 children born in Avon in 1991/92. The cohort have had eye examinations at different time points (see below) and there is a wealth of other data on relevant exposures (e.g. socioeconomic status of parents prior to enrolment and throughout the study; birth weight; breast feeding; early growth; parental myopia; close work; outdoor activities; intelligence etc). We will use the life course approach to analyses which will be the first time these methods will have been used in myopia research in children although we understand that data from the 1958 birth cohort are being examined in this manner. The following data on myopia and ocular dimensions are available from the ALSPAC cohort:
* undilated (ie without cycloplegic drops) autorefraction at ages 7, 10, 11 and 15 years. The prevalence of myopia (defined as less than 1.5D to take account of non-dilation) increased from 1.5% at the 7-year clinic (n=8003 right eyes) to 3.6% at the 10-year (n=7467 right eyes) and 4.9% at the 11 -year (n=6730 right eyes) clinics; 5500 attended and were autorefracted at the 15-yr clinic (data in preparation for analysis).
* vision related questionnaire data at 7 years and clinical examination at 7 years which included eye examination and the following measurements: LogMAR visual acuity, contrast sensitivity, stereo acuity, motor fusion; ocular alignment, eye preference, subjective accommodation.
* 2900 participants also have data on axial length and corneal curvature from the 15-year clinic
* Up-to-date optometric records for approximately 3000 participants who came to the 15-year clinic, and their siblings and parents
* Opportunistic autorefraction of approximately 2500 parents of the study participants who came to the 15-year clinic.
B788 - Comparison of human and mouse quantitative trait loci - 10/02/2009
We are requesting the P values for each marker from genomewide analysis of available samples in a number of ALSPAC phenotypes. We need the genome-wide set of P-values to compare with a similar set of measures obtained in a study of mouse complex phenotypes. Our justification for wanting to carry out this comparison is as follows:
Genetic mapping of disease models in rodents has long been expected to help with the identification of genes involved in human illness. Yet, while this is true for models that arise from abnormalities of a single gene, leading to new insights into diverse conditions such as obesity (leptin), susceptibility to infectious disease (toll receptors) and mental retardation (lissencephaly), the approach has been far less successful for phenotypes with a complex genetic basis. In a few instances common genes have been found: variants in CTLA4 increases risk of autoimmune disease in humans and a mouse model of type 1 diabetes (Ueda et al. 2003); a copy number variant in the same susceptibility gene (Fcgr3) contributes to immunologically mediated glomerulonephritis in humans and rats (Aitman et al. 2006).
The conservation of many physiological processes between the two species suggests that variation at genetic loci might be shared, and there is some evidence that this is so. Paigen and colleagues used linkage results to argue that more than half of human atherosclerosis QTLs are located in regions homologous to mouse QTLs (Wang et al. 2005a). However human linkage results are notoriously unreliable and, as Risch and colleagues pointed out, concordance is unlikely given that the genetic effect in humans depends on disease allele frequencies and such allele frequencies are unpredictable (Risch et al. 1993). The lack of power in human linkage studies compromises their use in comparison with the mouse findings. Furthermore, while the mapping of complex traits has proved to be an effective technique, delivering many thousands of quantitative trait loci (QTLs) its power is not matched by high resolution. The large confidence intervals into which both mouse and human QTLs were mapped made it difficult to exclude the possibility that overlap was coincidental.
Two developments allow us to revisit the question of the overlap between mouse and human QTLs, First, the advent of adequately powered genome-wide association studies in humans, which map genetic effects at high resolution, has proved to be a robust method for QTL identification (McCarthy et al 2007, Nature Reviews Genetics) Second, progress in mapping QTLs at high resolution in mice has yielded a map of over 900 QTLs for 100 phenotypes, each mapped to approximately 3 Mb (Valdar et al. 2006a). This was achieved using a quasi outbred population of mice, the heterogeneous stock (HS). While HS mouse QTLs are not mapped to the same resolution as is obtainable in human association studies, we hypothesize that it should be possible to perceive overlap between data sets.
In order to test this idea, we need a large set of data comparable to that mapped in the HS. All of our data, genotypes and phenotypes are freely available online (http://gscan.well.ox.ac.uk). We wish to compare the distribution of the mouse QTLs to the distribution of P-values found in human GWAS studies. Our mouse data set contains the following phenotypes that we wish to compare with the GWAS data from ALSPAC, Table 1 (appendix).
To carry out our analyses we need the P values for each marker. We do not need the individual genotypes, nor the individual phenotypes. We need the result of the analysis of association for every marker in the genome.
B790 - Genomewide association studies into circulating levels of adiponectin - 09/02/2009
Insulin resistance is a highly heritable trait and predisposes to both type 2 diabetes (T2D) and coronary heart disease (CHD). Whilst genome-wide association approaches have revealed multiple variants reproducibly associated with either T2D or CHD few of these variants are shared at a biological level. Additionally, there are no common variants yet reported to be reproducibly associated with biochemical measures of insulin resistance. Using serum adiponectin levels as a surrogate biomarker of insulin sensitivity, we aim to perform a meta-analysis of 3 genome-wide association studies and sought replication of our findings in 5 additional cohorts (including the ALSPAC children with non-fasting adiponectin levels measured at age 9).
Insulin resistance is a quantitative trait that predisposes to, and predicts independently, adverse metabolic and cardiovascular outcomes such as type 2 diabetes (T2D) and coronary heart disease (CHD)(1-3). Although factors such as obesity, diet and exercise importantly influence insulin resistance there is compelling evidence that it is strongly influenced by hereditary factors(4), yet few genetic determinants of insulin resistance have been described and none of these have been found to alter risk of T2D and CHD.
The precise mechanism through which insulin resistance has adverse impacts on metabolic and cardiovascular outcomes is as yet unclear and, indeed, may differ depending on the particular downstream pathology. Thus, while impaired insulin action per se may contribute directly to hyperglycemia, it has been suggested that the compensatory hyperinsulinemia that inevitably accompanies insulin resistance in the non-diabetic individual may have adverse consequences on the vasculature and liver that could predispose to athero-thrombosis(5, 6). However the precise quantification of insulin resistance in the epidemiological setting is challenging; "gold standard" measures of insulin resistance require technically demanding hyperinsulinemic clamp studies employing stable isotopes to dissect hepatic effects of insulin from those on muscle and fat, and such studies have consequently rarely been performed in populations large enough to generate meaningful information through genome wide association (GWA) studies(7).
We plan to undertake a large-scale meta-analysis of GWA studies (n = 14, 733) of circulating adiponectin levels in the hope that this will reveal common genetic variants that might at least in part explain the heritability of insulin resistance. Given the importance of insulin resistance as a precursor of both T2D and CHD, we anticipated that the identification of genetic variants associated with circulating adiponectin levels might be exerting their effects through an influence on insulin sensitivity/resistance and that such variants might therefore modulate the risk of T2D or CHD, or indeed both.
1. Chen, K.W., Boyko, E.J., Bergstrom, R.W., Leonetti, D.L., Newell-Morris, L., Wahl, P.W., and Fujimoto, W.Y. 1995. Earlier appearance of impaired insulin secretion than of visceral adiposity in the pathogenesis of NIDDM. 5-Year follow-up of initially nondiabetic Japanese-American men. Diabetes Care 18:747-753.
2. Beck-Nielsen, H., and Groop, L.C. 1994. Metabolic and genetic characterization of prediabetic states. Sequence of events leading to non-insulin-dependent diabetes mellitus. J Clin Invest 94:1714-1721.
3. Meigs, J.B., Wilson, P.W., Fox, C.S., Vasan, R.S., Nathan, D.M., Sullivan, L.M., and D'Agostino, R.B. 2006. Body mass index, metabolic syndrome, and risk of type 2 diabetes or cardiovascular disease. J Clin Endocrinol Metab 91:2906-2912.
4. Laws, A., Stefanick, M.L., and Reaven, G.M. 1989. Insulin resistance and hypertriglyceridemia in nondiabetic relatives of patients with noninsulin-dependent diabetes mellitus. J Clin Endocrinol Metab 69:343-347.
5. Despres, J.P., Lamarche, B., Mauriege, P., Cantin, B., Dagenais, G.R., Moorjani, S., and Lupien, P.J. 1996. Hyperinsulinemia as an independent risk factor for ischemic heart disease. N Engl J Med 334:952-957.
6. Semple, R.K., Sleigh, A., Murgatroyd, P.R., Adams, C.A., Bluck, L., Jackson, S., Vottero, A., Kanabar, D., Charlton-Menys, V., Durrington, P., et al. 2009. Postreceptor insulin resistance contributes to human dyslipidemia and hepatic steatosis. J Clin Invest.
7. Howard, G., O'Leary, D.H., Zaccaro, D., Haffner, S., Rewers, M., Hamman, R., Selby, J.V., Saad, M.F., Savage, P., and Bergman, R. 1996. Insulin sensitivity and atherosclerosis. The Insulin Resistance Atherosclerosis Study (IRAS) Investigators. Circulation 93:1809-1817.
B783 - COMT genotype pregnancy outcome psychosis and cognitive abilities - 09/02/2009
(No outline received).
B778 - Moderation by foetal and maternal NQO1 Pro187Ser rs1800566 genotype of the effects of prenatal tobacco exposure - 06/02/2009
Summary
Maternal smoking during pregnancy is a well-established and preventable risk factor for low birthweight and its sequelae of poor physical, cognitive and behavioural development, excess morbidity, and increased rates of both perinatal and adult mortality. Preliminary findings from genetic epidemiology studies suggest that the degree to which prenatal tobacco exposure depresses birthweight may be moderated by foetal and maternal genotype for NQO1 Pro187Ser (rs1800566). We propose to genotype this variant in mothers and children participating in ALSPAC to test hypotheses about the moderating effects of maternal and foetal rs1800566 genotype on the effects of prenatal tobacco exposure to reduce birthweight, shorten gestation, and alter postnatal physical, cognitive, and behavioural development.
Background
Maternal smoking during pregnancy is a well-established and preventable risk factor for low birthweight (less than 2,500g) and its sequelae of poor physical, cognitive and behavioral development, excess morbidity, and increased rates of both perinatal and adult mortality (Kramer, 2003). The primary causes of low birthweight are preterm birth and intrauterine growth restriction (IUGR). The consequences of IUGR include both short-term and long-term morbidity and permanent deficits in growth and neurocognitive development (Kramer, 2003). Epidemiological studies have shown that maternal smoking is associated with both short gestation and IUGR (Kramer, 2003). Mothers who quit smoking while pregnant have longer gestations and heavier newborns than those who continue to smoke (Lumley, Oliver, Chamberlain, & Oakley, 1998). This fact is recognized in public policy: in the UK, formal smoking cessation programs are recommended as part of antenatal care to prevent low birthweight (Health Development Agency, 2004).
Preliminary findings from studies in genetic epidemiology (Sasaki et al., 2008; Price, Grosser, Plomin & Jaffee, in press) suggest that the degree to which prenatal tobacco exposure depresses birthweight may be moderated by foetal and maternal genotype for NQO1 Pro187Ser (rs1800566). To date, no study has replicated these initial findings, nor tested the effects of both maternal and foetal rs1800566 genotype, nor investigated the possibility that rs1800566 genotype interacts with prenatal tobacco exposure to influence postnatal physical, behavioural, and cognitive development.
Methods
Data collection. We propose to genotype approximately 10,000 mothers and 10,000 children participating in the ALSPAC study for the NQO1 Pro187Ser variant (rs1800566).
Existing data required
Concept
Specific Measure
Person
Source
Time Point(s)
Demographic variables (age, sex, ethnicity, marital status, family structure, SES, education, employment, income etc.)
Family
Questionnaire
Antenatal
Pregnancy health variables (nulliparity, pre-eclampsia, IUGR, gestational diabetes etc.)
Mother
Questionnaire, medical records
Antenatal
Parental anthropometrics (height weight)
Mother, Father
Questionnaire
Antenatal
Pregnancy exposure variables (tobacco, alcohol and drug use; chemical exposure; diet; nutrient supplementation; stress; life events; partner cruelty; lack of social support)
Mother
Questionnaire
Antenatal
Birth/delivery variables (weight/length, placental weight, gestational age, Caesarian), perinatal health
Child
Questionnaire, medical records
Birth/perinatal period
Childhood head injury
Child
Questionnaire
Birth - 4 years
Childhood temperament
Carey
Child
Questionnaire
24 months
Childhood behaviour
SDQ
Child
Questionnaire
42 - 157 months
ADHD
Child
Questionnaire
166 months
Antisocial behaviour
Child
Questionnaire
169 months - 198 months
Psychotic symptoms
Child
Questionnaire
140 months - 198 months
Adolescent substance use (tobacco, alcohol, drugs)
Child
Questionnaire
157 months - 198 months
Language development
McCarthy
Child
Questionnaire
24 months
Cognitive ability
WISC
Child
Clinic test
8 years
Scholastic achievement
Child
Questionnaire
166 months
Anthropometrics (Height, weight)
Child
Questionnaire
Birth - 157 months
Parental antisocial behaviour (antisocial behaviour as children or adults; contact with police; criminal convictions)
Mother, father
Questionnaire
Antenatal - 145 months
Childhood postnatal experiences (maternal depression and anxiety, parental discipline)
Mother
Questionnaire
Birth - 145 months
Parental postnatal substance use (tobacco, alcohol, drugs)
Mother, father
Questionnaire
Birth - 145 months
Data Analysis. Hypotheses about effects on birthweight and gestational age will be tested using linear models incorporating terms for prenatal tobacco exposure, maternal genotype, foetal genotype, interaction between maternal genotype and prenatal tobacco exposure, interaction between foetal genotype and prenatal tobacco exposure, plus relevant covariates (including demographics, pregnancy and antenatal health variables, and parental physical and behavioural characteristics). Analyses will be stratified by ethnicity to guard against spurious associations due to population admixture. Hypotheses concerning low birthweight and premature gestation will be tested similarly, but using a logistic regression model. Hypotheses about trajectories of postnatal physical, behavioural, and cognitive development will be tested using growth curve models and growth mixture models; in addition, mediation analyses will be conducted to test whether postnatal development is conditionally independent of genotype and prenatal tobacco exposure after controlling for any effects on birthweight and gestational age. Hypotheses about the effects of prenatal tobacco exposure will test for heterogeneity of the effects with respect to mode of exposure (maternal smoking/maternal exposure to second hand smoke), dose, and timing of smoking cessation. A parallel set of analyses will be conducted using paternal tobacco exposure as the environment of interest in order to validate the inference of intrauterine effects. Analyses will be conducted to assess the possible influence of attrition in the sample on the outcomes of interest. If necessary, informative missingness will be explicitly modelled.
References
Health Development Agency. (2004). The evidence of effectiveness of public health interventions - and the implications.
Kramer, M. S. (2003). The epidemiology of adverse pregnancy outcomes: An overview. Journal of Nutrition, 133, 1592S-1596S.
Lumley, J., Oliver, S., Chamberlain, C., & Oakley, L. (1998). Interventions for promoting smoking cessation during pregnancy. Cochrane Database of SystematicReviews, Art. No.: CD001055. DOI: 001010.001002/14651858.CD14001055.pub14651852.
Price, T. S., Grosser, T., Plomin, R., and Jaffee, S. R. (in press). Fetal genotype for the xenobiotic metabolizing enzyme NQO1 influences intrauterine growth among infants whose mothers smoked during pregnancy. Child Development.
Sasaki, S., Sata, F., Katoh, S., Saijo, Y., Nakajima, S., Washino, N., et al. (2008). Adverse birth outcomes associated with maternal smoking and polymorphisms in the N-nitrosamine-metabolizing enzyme genes NQO1 and CYP2E1. American Journal of Epidemiology, 167, 6.
B780 - Development of conduct problems and violence in England and Brazil - 04/02/2009
DEVELOPMENT OF CONDUCT PROBLEMS AND VIOLENCE IN ENGLAND AND BRAZIL
This project will compare the development of violent behaviour among adolescents in ALSPAC and in a Brazilian birth cohort also born in 1993. The critical question for investigation is why Brazilian youth develop much higher levels of violent behaviour by late adolescence than English youth, despite quite similar levels of conduct problems in childhood.
BACKGROUND
Out of 83 countries surveyed worldwide, Brazil has the 5th highest rate of youth homicide (51.6 per 100,000) and England and Wales ranks 71st (0.4 per 100,000) [1]. The high rate of homicide in Brazil appears to reflect the tip of a wave of serious and violent crime. Despite the very high rates of these problems in Brazil, there is almost no empirical evidence about their causes.
Conduct problems are disruptive behaviours including physical aggression, lying, stealing, vandalism, and truancy. Studies in Europe, North America and Australasia have shown that conduct problems which start in childhood are particularly predictive of persistent antisocial behaviour, crime and violence. An obvious question is whether a high level of childhood conduct problems lies behind the high level of crime and violence in Brazil. It appears that it does not. One careful investigation of conduct and oppositional defiant disorders among children aged 7-14 years found rates of 7.0% in Brazil and 5.0% in England and Wales [2]. If this finding is replicated, it suggests that the higher rates of crime and violence in Brazil compared with England might be explained by different social processes during adolescence. This is the subject of the proposed study.
The theoretical model that will inform our investigation is Moffitt's influential taxonomy of early onset and adolescent onset antisocial behaviour [3]. Moffitt argues that early onset and persistent antisocial behaviour has its roots in interacting biological and social stresses in early life. By contrast, antisocial behaviour that emerges in the teenage years is driven mainly by the strains of role transitions and delinquent peer influence. Evidence to date suggests that serious violence is primarily committed following early onset and persistent antisocial behaviour. However, recent work shows that another pattern of antisocial behaviour needs to be distinguished. Some children, referred to as a "childhood limited group" show early onset conduct problems but desist from antisocial behaviour during adolescence [4]. Our analyses of ALSPAC data have identified a group of this kind, clearly differentiated from children with persistent early onset conduct problems on a range of early predictors [5].
Working from this model, the higher level of adolescent violence in Brazil than in England might be accounted for in a variety of ways. First, more children with early onset conduct problems might desist in adolescence in England. Second, among early onset and persistent offenders, the frequency of violent acts might be higher among Brazilian adolescents. Third, there might be a higher prevalence of adolescent onset offenders in Brazil. Fourth, adolescent onset offenders in Brazil might commit violent acts more frequently or for longer than their English counterparts. Of course, any combination of these four possibilities might also account for the higher level of adolescent violence in Brazil than in England.
In addition, there are many demographic, social, cultural, and criminal justice system differences between the two countries that might account for different patterns of violent development. Several distinctive demographic, social and cultural characteristics of Brazilian society stand out as potentially important; these include marked income inequality and absolute poverty, educational failure and school drop-out, and the occurrence of subcultures of gangs with high rates of drug use, especially in areas of concentrated poverty [6]. We hypothesise that this social context poses specific risks for the development of violence during adolescence that have not been documented elsewhere. This needs to be tested in high quality, well-matched, cross-national longitudinal studies.
PROPOSED STUDY
We propose to investigate the prevalence, frequency and continuity in conduct problems and violence between the ages of 11 and 17-18 years in ALSPAC and a similar birth cohort (also born in 1993) in Pelotas, southern Brazil, and to investigate possible mechanisms for different rates of these problem behaviours between the two sites. Collaboration has been agreed with the directors of the Pelotas study.
The Pelotas 1993 Cohort Study is a population based birth cohort study [7] of all 5,249 newborns delivered in hospitals in the city of Pelotas in 1993. Nearly all (greater than 99%) of the city's births occur in hospitals. Subsamples were visited at the ages of one, three and six months and one and four years. In 2004-5 it was possible to trace 87.5% of the cohort at ages 10-12 years. The whole cohort was most recently interviewed at age 15 in 2008, and the next wave of interviews will be conducted in 2011, when cohort members are aged 18. Extensive biosocial data have been collected through the course of the study. Many hypothesised predictors of conduct problems and violence have been measured with comparable instruments in Pelotas and ALSPAC.
In both ALSPAC and in the Pelotas study, cohort members' conduct problems were measured at about age 11 using the Strengths and Difficulties Questionnaire and the Development and Well-Being Assessment. At age 17+, a self-report delinquency questionnaire (developed in The Edinburgh Study of Youth Transitions and Crime) is being administered to ALSPAC participants (personal communication with Matthew Hickman). This questionnaire includes extensive information on involvement in fights, gangs and use of weapons, as well as other forms of delinquency. The same questionnaire will be translated for use in the next wave of interviews with Pelotas study participants at age 18. These measures would provide the key outcome variables for this research, and other data on antisocial behaviours would be used from each study where appropriate.
Analyses would address the following questions. 1) Are early childhood predictors of conduct problems at age 11 similar in Pelotas and ALSPAC? 2) Is there similar continuity from childhood conduct problems to adolescent violence in Pelotas and ALSPAC? 3) Are high rates of violence in Pelotas compared with ALSPAC explained by more youth being involved in violence, or by violent youths committing more violent acts? 4) To what extent is the high rate of adolescent violence in Pelotas compared with ALSPAC explained by differences in rates of: childhood biosocial risks, educational failure, teenage parenthood, stressful life events, drug use, gang involvement, concentrated poverty, and deprived neighbourhood contexts?
REFERENCES
1. Waiselfisz JJ. Mapa da Violencia: Os Jovens da America Latina 2008. Brasilia, DF, Brazil: RITLA, 2008.
2. Fleitlich-Bilyk B, Goodman R. Prevalence of child and adolescent psychiatric disorders in southeast Brazil. Journal of the American Academy of Child and Adolescent Psychiatry 2004;43(6):727-734.
3. Moffitt TE. Life-course-persistent and adolescence-limited antisocial behavior: A 10-year research review and a research agenda. In: Lahey BB, Moffitt TE, Caspi A, editors. Causes of conduct disorder and juvenile delinquency. New York: Guilford, 2003:49-75.
4. Rutter M, Kim-Cohen J, Maughan B. Continuities and discontinuities in psychopathology between childhood and adult life. Journal of Child Psychology and Psychiatry 2006;27(3):4.
5. Barker ED, Maughan B. Differentiating early onset persistent versus childhood limited conduct problem youth. American Journal of Psychiatry submitted.
6. Marsiglia RG, Silveira C, Carneiro Junio N. Brasil: indicadores sociodemograficos e caracteristicas das politicas publicas na decada de 1990. In: Mello MF, Mello AAF, Kohn R, editors. Epidemiologia da saude mental no Brasil. Porto Alegre, Brazil: Artmed, 2007:17-37.
7. Victora CG, Hallal PC, Araujo CLP, Menezes AMB, Wells JCK, Barros FC. Cohort Profile: The 1993 Pelotas (Brazil) Birth Cohort Study. International Journal of Epidemiology 2007; Advanced electronic access: doi:10.1093/ije/dym177.
B779 - Genome-wide association studies of cognitive functions in the SCORM and ALSPAC cohorts - 03/02/2009
(No outline received).
B777 - Investigating the role of novel variants associated with age at menarche in fetal and childhood growth - 02/02/2009
The regulation of the onset of menarche is not fully understood. Mean age of menarche is approximately 13 years in Caucasians, but has decreased over time in many populations and this reduction has been attributed to improved nutrition during recent history. One of the triggers for onset of puberty in girls is thought to be an increase in fat mass to greater than approximately 20% body fat. While non-genetic factors are obviously important in menarche, twin and family studies suggest a significant genetic component with at least 50% heritability (1-3), although linkage studies have not identified any strong candidate genes (4).
We have been involved in a meta-analysis of genome wide association studies to identify novel genetic variants associated with age at menarche. In Exeter we analysed imputed genome wide SNP data from the InChianti study of older people and collaborated with other studies from the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) consortium: in total, 15,661 women were included in the meta-analysis.
We identified 3 independent signals with p values less than 1x10-6, one of which reached the conventional genome-wide significance threshold of less than 5 x 10-8. In addition there were two SNPs neighbouring genes which are excellent candidates for involvement in variation in age at menarche. We would therefore like to genotype these 5 SNPs in ALSPAC, to replicate our initial findings.
In addition, the ALSPAC study provides an excellent opportunity to investigate the longitudinal role of these genes in childhod growth and development leading to the onset of puberty in both boys and girls.
Genotypes:
We would like to genotype (at Kbioscience) all ~20,000 ALSPAC samples.
The rs numbers of the selected SNPs are given in the appendix.
Phenotypes:
1. Age at menarche (including birth year as covariate) for all mothers and female offspring, as available.
2. Puberty phenotypes, eg. Age of secondary sexual characteristics
3. Growth measures in infancy and childhood (height, leg length, sitting height, weight and BMI, lean/fat/bone mass from DXA scan, waist circumference, WHR, skinfolds, birth weight, length & head circumference (& relevant covariates: gestational age, parity, twins, maternal smoking), where available)
4. Covariates of age at menarche to check if genotype is acting through them/to reduce variance in outcome: year of birth, BMI, height, ethnicity as genotype frequency may alter with ethnic origin and confound analyses.
Plans for meta-analysis:
The ALSPAC data on association with age at menarche will be meta-analysed with the original genome-wide association data and also other replication efforts, including the British Women's Heart & Health Study (BWHHS).
The longitudinal study of ALSPAC children will provide a large dataset on genetic association of confirmed variants that affect age at menarche and their role in pubertal development. However, the effects of the polymorphisms are likely to be modest and we will need to meta-analyse data from multiple studies using our own studies and extensive collaborations. These may include the Northern Finland Birth Cohorts of 1966 and 1986, 1958 British Birth Cohort and 1946 Birth Cohort. The statistical support for true associations with puberty will be greatly increased in the meta-analysis, relative to the individual studies.
References
1. Snieder, H., MacGregor, A.J. and Spector, T.D. (1998) Genes control the cessation of a woman's reproductive life: a twin study of hysterectomy and age at menopause. J Clin Endocrinol Metab, 83, 1875-80.
2. van den Berg, S.M. and Boomsma, D.I. (2007) The familial clustering of age at menarche in extended twin families. Behav Genet, 37, 661-7.
3. Towne, B., Czerwinski, S.A., Demerath, E.W., Blangero, J., Roche, A.F. and Siervogel, R.M. (2005) Heritability of age at menarche in girls from the Fels Longitudinal Study. Am J Phys Anthropol, 128, 210-9.
4. Anderson, C.A., Zhu, G., Falchi, M., van den Berg, S.M., Treloar, S.A., Spector, T.D., Martin, N.G., Boomsma, D.I., Visscher, P.M. and Montgomery, G.W. (2008) A genome-wide linkage scan for age at menarche in three populations of European descent. J Clin Endocrinol Metab, 93, 3965-70.
B776 - Is there such a thing as a sweet tooth - 29/01/2009
Is there such a thing as a "sweet tooth" that is acclimatisation to sweetness in foods. Is it possible that if an individual is exposed to foods rich in sugar that they can develop a "sweet tooth" and if a person is classified as having a "sweet tooth" does it matter?
Does having a diet rich in sweet foods impact on the nutritional quality of the diet? Does intake of sugary foods result in an excessive intake of non-milk extrinsic sugars, total energy and do they displace healthier food items from the diet? Do children who don't have a "sweet tooth" have a healthier diet than those with, and is there value in recalibrating a "sweet tooth"?
Subjects:
Avon Longitudinal Study of Parents and Children (ALSPAC) study is an ideal population in which to investigate these questions as it has a wealth of dietary data collected at several time points and valuable questionnaire data.
Data:
Dietary data has been collected using two methods. Food frequency questionnaire data is available at ages 3 years, 4 years, 7 years and 9 years. Food record data (3-day) is available on approximately 1000 children at 4 months, 8 months, 18 months, 43 months and 5 years and for approximately 7000 at 7 years, 10 years and 13 years. In addition there is age of introduction to various food items, including fizzy drinks, chocolate and sweets collected at 6 months and 15 months. The parents/carers were asked at 65 and 78 months if their child seemed to prefer sweet foods, these questions can be used to identify children with a 'sweet tooth'.
Methods:
1. Parent identified 'sweet tooth':
Analysis will be carried out to identify if there is any difference between the diets of children who were identified by their parents as having a "sweet tooth" and those who were not.. We will investigate if these children were introduced to sweet foods at an early age. Using the longitudinal data we will investigate if their diet tracks over time.
2. NME intake at 7 - used to identify those eating most sugar:
We will calculate non-milk extrinsic sugar intake at 7 years and divide intake into quintiles. We will compare the diets of children in the upper quintiles with the lower quintiles and indentify differences in intakes of nutrients and foods. We will track children's NME sugars intake from 7 years to determine if they remain within or cross centiles at age 10 and 13 years.
3. Early Introduction to sweet foods:
We will indentify children who were introduced to sweet foods at an early age, and identify if exposure to sweet foods at an early age leads to a higher intake of sugars in later diet.
Staff
Louise Jones Research Nutritionist (60% for 6 months) will perform the analyses and prepare manuscripts and reports.
Pauline Emmett Senior Research Fellow in nutritional epidemiology will will suppy expertise in analysis and manuscript preparation (2 hours per week)
Colin Steer will provide statistical support (1 hour per week)
Steve Gregory will provide data and manuscript preparation support (20% for 6 months)
The work will be part of the School Food Trust research strategy.
B775 - Functional Vision in children with disabilities or learning difficulties - 29/01/2009
his project is a fellowship application for CW. Two similar applications -one for a "new blood" CSL post, and one for an NIHR Career Development Fellowship are proposed. The programme for each is identical, and includes some work on ALSPAC data - see Study 2 below
Functional vision and disability in childhood
Functional vision (how well a person's vision equips them for the tasks they need to carry out) includes both "eye" and "brain" capabilities and is recognised by the International Council for Ophthalmology (ICO) as a key outcome for rehabilitation and support strategies. This fits into the broader context of the global World Health Organisation (WHO) emphasis on Functioning, Disability and Health as important measures of people's health and well-being. There is increasing evidence that "cerebral visual impairment" (CVI) is a cause of functional vision problems in children. Although many professional bodies in the UK and the National Service Framework for children advocate a review of visual function as part of the assessment of a child with disabilities, recommendations for registration of sight impairment (which aids access to support services) include only visual acuity and visual field deficits and do mention include CVI. However services that carry out functional vision assessments, including CVI, as part of a team approach to managing disability have been set up and commended in a government report. However, there are few data available on effectiveness of these services.
Estimates of the proportion of children with disabilities who have functional vision problems vary from 8% to 80%, depending on the definition used. Forty-four percent of children on the UK cerebral palsy (CP) register have associated visual impairment. In a small pilot study of 7-yr old children (not in ALSPAC) conducted by myself and colleagues - 5/11 children with a statement of educational special needs (SEN) had a previously unknown problem that might be expected to affect their functional vision (field loss, eye movement inaccuracies, failure of accommodation, 3+ yrs delay in visuo-perceptual abilities) whilst none of the 8 age-matched controls did. This study was hampered by very low recruitment but the results support the possibility that there may be "unmet need" in terms of visual morbidity amongst children with statements of SEN (results in preparation).
Testing and supporting functional vision in children with disabilities - a "complex intervention".
A key problem in designing, funding and running services in this area of healthcare provision for children with functional vision impairments is the lack of evidence on effectiveness, acceptability and cost-effectiveness, of interventions. The new MRC Guidance on Complex Interventions provides a useful conceptual framework to evaluate existing and guide new research. In line with this advice, I propose a 5-year programme of work designed to develop a complex intervention that will include assessing a child's "functional vision" and individualising their support accordingly. I will review existing evidence, carry out qualitative and physical assessments to characterise the deficits in more detail, and estimate the effectiveness of intervention strategies in pilot studies. I will then design a complex intervention and a study in which it can be evaluated.
PROPOSED RESEARCH IN THIS 5 YEAR PROGRAMME relevant section to ALSPAC:
Study 2. I will continue analysis of existing observational data within the Avon Longitudinal Study of Parents and Children (ALSPAC). These analyses will include:*
(a) contribution of CVI symptoms (elicited in a specific set of targeted questions) and other visual deficits (eg reduced acuity or contrast sensitivity) to educational, motor and social outcomes in children with ICD-10 diagnosed difficulties (ie prevalence of CVI as a co-pathology)
(b) self-esteem using a 12-item shortened form of Harter's Self Perception Profile for Children asked at age 8 (Harter, 1985) and peer relations (Questions from the Cambridge Hormones and Moods project Friendship questionnaire at 11y and 13y) for children with CVI compared to those without
(c )psychological well-being for mothers and mothers' partners, of children with CVI and other visual deficits, as compared to that of mothers and their partners where the children do not have CVI symptoms. without (using the anxiety subscale of the Crown Crisp Experiential Index (Crown & Crisp, 1979) and the Edinburgh Postnatal Depression scale (Cox, Holden, & Sagovsky, 1987),when child was 11y).
(d) contribution of any genetic factors that may contribute to CVI in children eg such as the deletion on chromosome 7q11.23, already identified as causing "Williams syndrome", in which functional vision is impaired because of impaired processing of visual input by the brain.
Funding-The only extra resource needed is a pro rata contribution to the time for a statistician to prepare specific files and help analyze and write up the data. Funds for this will be applied for as needed.
Further studies (1 and 3 - 5) in accompanying proposal will be conducted, with new data collection, not involving ALSPAC.
B773 - Replication/meta-analysis of genome wide association scans for eye quantitative traits - 29/01/2009
Replications of eye_quantitative_traits hits Genome-wide significant :
For genome-wide significant hits in our respective cohorts for which we (reciprocally) are seeking replication in each other cohort, lead for follow up and publication would be given to the group seeking replication. Effect size , P-value for association at the specific SNPs and method of analysis would be requested (ALSPAC's GWA analyses are ongoing). All work and analyses would be acknowledged in the publications and the replicating group would provide authors for the papers written by the leading group, whatever the results.
The summary of the measures used in our analyses in the 2 croatian population-based studies are
attached with this proposal. We are seeking data in the ALSPAC study for one SNP which reached genome wide significance in our metaanalysis of ocular axial length in the 2 Croatian isolates,and showed the same magnitude and direction of effect in our 2 independent isolates. We would also like, if the meta-analysis proposal (below) was not to go ahead , to get similar data on 2 additional regions (2 SNPs) that showed strong evidence of association with axial length, in females only. These do not reach genome wide significance in the initial genotyped set but show strong cluster of association in the imputed dataset and make biological sense.
Meta-analysis on GWA data for eye traits on a collaborative basis:
This analysis required harmonisation of the traits analysed before pooling data. Each group would analyse his own dataset. We can include more trait data than in the replication study, to maximise the value of the analyses for each group.Material tranfert agreements would be drawn to insure that the shared analysis results are not passed on to third party without formal approval. We propose to use rank normalised data post adjusted for age and sex for axial length and refractive error. This is because spherical equivalent usually has a non normal distribution. We propose to also perform the analysis separately for each gender. Analysis would be done using an additive genetic model, for example using the function formetascore of the R package GenABEL for easy merging of the data.
The output files to be exchanged and meta-analysed lay-out would be :
(1) " name": SNP rs number
(2) "chromosome"
(3)"position"
(4)"strand" ideally all standardise to the top strand using build 36
(5) "allele1"
(6)"allele2"
(7)"build"
(8)"effallele" allele for which effect is reported
(9)"effallelefreq"
(10)"n" number of individuals with genotypes and phenotypes available for that SNP
(11) "beta"
(12) "sebeta"
(13)"p" uncorrected P-value for the additive test
(14)"pgc" above corrected after genomic control correction
(15)"lambda" estimated inflation factor (genomic control lambda) for the test
(16)"pexhwe" exact P-value for HWE test
(17) "call" Call rate for the SNP
Results from this meta-analysis would be described in a paper/papers with shared authorship between the groups and 2 co-corresponding authors, one from each group.
B772 - The interaction of genetic effects with smoking in pregnancy and NO2 exposure in early life on child neurocognitive development - 29/01/2009
Recently two studies from the Menorca cohort have investigated the role of genes associated with detoxification (1, 2). These studies have reported interactions between GSTM1 with maternal smoking in pregnancy and GSTP1 with indoor NO2 exposure at 3 months of age on child cognitive development at 4 years as measured by the McCarthy scale. Similar analyses of smoking with GSTT1 found no interaction. As far as we know no other studies have examined these issues. The Menorca cohort was relatively small (N~400) and currently has no DNA from mothers.
Early in 1993, about 1000 families from the ALSPAC cohort participated in a study to assess indoor air quality. Passive diffusion tubes were left exposed, usually in the child's bedroom, over a two week period from which average NO2 concentrations (parts per billion) were obtained. These families also completed a questionnaire about the use of gas appliances, portable heaters (gas or paraffin), smoking, ventilation in the home, and external sources of NO2 (level of traffic outside home). Similar questions were asked in pregnancy and at 8 months for the whole cohort.
Maternal cigarette smoking is assessed at multiple times during pregnancy.
Child cognitive development was assessed at 49 months using WPPSI but only for Children in Focus subsample and at 8 years using WISC for the whole cohort.
It is proposed to follow a similar strategy as adopted in the Menorca studies. In respect of NO2 exposure, both actual and indirect measures of exposure are possible. Indirect assessments could involve using questionnaire data on the use of gas appliances or alternatively creating a predictive model of actual exposure based upon gas usage, other sources of NO2 and ventilation. Both these methods would permit the use of larger numbers whereas analyses on actual exposures would be restricted to the 1000 families involved in the indoor air study. For smoking, exposure can be assessed as a continuous variable (assuming linearity) or as a categorical variable.
Unlike the Menorca studies, we propose to extend the analyses to consider cognition at 8y (to investigate the attenuation with age) and the maternal genotype. The maternal genotype may affect the child during pregnancy. The metabolites of environmental toxins can cross the placenta with the potential to disrupt the developing fetus (3). Consequently, the ability of the mother to metabolise these toxins may have a direct impact on the fetus.
1.MoralesE, SunyerJ, JulvezJ, Castro-GinerF, EstivillX, TorrentM, de Cid R.GSTM1 polymorphisms modify the effect of maternal smoking during pregnancy on cognitive functioning in
preschoolers. Int J Epidem (in press)
2.MoralesE, JulvezJ, TorrentM, de Cid R, Guxens M, Bustamante M, SunyerJ. Association of early life exposure to household gas appliances and indoor NO2 with cognition and attention behavior in preschoolers. Am J Epidem (submitted)
3. Perera FP, Jedrychowski W, Rauh V, Whyatt RM. Molecular epidemiologic research on the
effects of environmental pollutants on the fetus. Environ Health Perspect 1999;107:451-60.
Data required
Concept
Specific measure
Person
Source
Time point(s)
IQ
WPPSI, WISC
Child
Clinic
49m, 8y
Air Quality
NO2
Substudy
Environmental
Exposures
Smoking, gas usage, etc
Mother
Questionnaire
Pregnancy to 8m
B771 - Developmental programming and DNA methylation - 28/01/2009
The aim of the proposed programme of work is to establish the role of epigenetic mechanisms (DNA methylation) in the developmental programming of disease in later life. This will involve establishing both the determinants of epigenetic variation (i.e. the relationship between various exposures and methylation status in DNA at available time points) and the consequences of epigenetic varaition (i.e. the relationship between DNA methylation status and phenotypic outcomes).
In addition, the transmission of epigenetic patterns from mother to child will be investigated. The role of maternal epigenetic signatures in determining child epigenotype and phenotype will be explored.
A further area of interest is the role of common genetic variation in dictating epigenetic patterns. Using existing ALSPAC genotype data will we be able to explore whether genotype (both maternal and child) impacts upon epigenetic variation. When epigenotype is considered a a phenotype, a Mendelian randomisation approach can be used to explore the determinants of epigenetic status.
This work will be pursued via a varity of funding opportunities including the following;
1. ERC Programme Grant: "Epigenetic Epidemiology; the role of epigenetic variation in common complex disease". 2 million euro, submitted Dec 2008, outcome July 2009.
2. Biomedical Research Centre in Ageing, Newcastle University: "DNA methylation and ageing". £60K, submitted Feb 2009, outcome April 2009.
3. MRC Project grant: "Epigenetic mechanisms in the developmental programming of obesity". For submission May 2009.
4. Wellcome Trust; "A comparative study of epigenetic variation in low and middle income country settings with a UK adolescent birth cohort". For submission July 2009.
Studies will involve array-based approaches to define gene loci that demonstarte epigenentic variation (MeDIP-chip, Illumina BeadArray probable platforms) in a small sub-set of samples (typically 24 paired; exposed/unexposed, case/control or 2 extremes of phenotype) followed by quantatitive DNA methylation (qCpG) analysis of specific loci in a substantial number of samples (n=1000+). qCpG analysis will be undertaken using Pyrosequencing or Sequenom MassArray. A candidate gene-based approach utilising qCpG without requiring array analysis is also feasible.
DNA requirements for microarray are 1ug at 100ng/ul. For subsequent qCpG analysis the same quantity is required to analyse 5-10 loci.
Data will be required on a range of exposures and phenotypes at serail timepoints and in both children and mothers. An outline description of the data required is provided below;
Phenotypes of multiple outcomes that show evidence of developmental programming including; obesity and related traits, cardiovascular disease and related traits in children from the ALSPAC cohort; Pre- and postnatal exposures which may plausibly influence programming including maternal smoking and nutritional variables and maternal and child genotypes that can be used as instrumental variables (e.g. MTHFR) ; other prenatal exposures and socio-demographic variables. DNA methylation profiles of children linked to phenotype and exposure data.
B774 - The paediatric origins of COPD - 27/01/2009
The hypothesis that a disturbed early development of the lungs may underlie the susceptibility to COPD is well accepted. There is sparse epidemiological evidence that early life events, including antenatal influences on lung growth, program a child to be at increased risk for future COPD.COPD may not only have its origins, but also its first symptoms in early childhood. In a report based on the Tucson Children's Respiratory Study, Martinez et al. proposed three patterns of wheezing during the first six years of life, i.e. transient early wheezing in the first three years of life, non-atopic wheezing in preschool years and IgE-mediated wheeze or asthma. Children with transient early wheezing who do not develop asthma, usually wheeze in the first years in response to environmental exposures such as maternal smoking or viral infections. We put forward the hypothesis that these symptoms constitute the first signs of disturbed early lung development and lung growth and as a corollary hypothesis that this may reflect later development of COPD. This is supported by the replicated findings that transient early wheeze is associated with lower lung function levels up to age 16, even when the symptoms of wheeze have disappeared. Since the level of lung function, expressed as FEV1, has been shown to track over time, it is plausible that infants with lower lung function levels have an increased risk to develop COPD later in life. A limiting factor in research on this hypothesis is the huge logistic difficulty of studying the effect of early life events with respect to a disorder that only becomes apparent 50-60 years later. Therefore research must rely on indirect evidence and one such a feasible type of research is the investigation of common underlying genes. The aim of our study is to investigate whether replicated genes of COPD are associated with transient early wheeze and the level of lung function in children. The current birth cohorts under study (PIAMA and KOALA) allow us to analyze data from 2500 children and take into account important environmental stimuli like in utero and early childhood smoke exposure and air pollution. Moreover, a birth cohort in England will provide data to replicate our positive findings.There is increasing evidence from studies in adults that genes involved in the response to oxidative stress are associated with COPD development. The strongest and most consistent effects on COPD have been found in the genes of glutamate-cysteine ligases (GCL), glutathione S-tranferases M1 (GSTM1) and P1 (GSTP1), and superoxide dismutase 3 (SOD3). Other replicated genes of COPD are involved in the balance between proteases and antiproteases in the lungs, such as alpha1-antitrypsin (AAT) deficiency (AAT), Tissue Inhibitors of MMPs (TIMP)-1, transforming growth factor (TGF)-b1, Tumor necrosis factor (TNF)-a and Serpine2. In addition, we aim to use the positive findings of a currently performed genome wide association study (GWA) on COPD in adults (COPACETIC). This allows us to verify if genes that are found by GWA in a COPD cohort and replicated in other cohorts of adults are also associated with low lung function and wheezing phenotypes in childhood.This study aims to provide more insight in the natural history and pathogenesis of COPD. In addition, it may offer opportunities to identify susceptible individuals at the earliest stages of the disease, when preventive strategies are most effective.
The data required will be early wheezing phenotypes and lung function measurements, tobacco smoke exposure and usual confounding variables for early life asthma studies (already compiled).
B770 - Pubertal timing and depressive symptoms in adolescent girls The roles of family and peer relationships - 23/01/2009
(No outline provided).
B768 - Genomewide association study meta-analysis for birthweight gestational age and related phenotypes - 21/01/2009
ALSPAC is one of few studies (currently less than 5) available which has access to extensive phenotypic data measuring birthweight and gestationsal age, related maternal and neonate variables and genomewide genetic data. As an important player in the newly formed Early Growth Genetics (E.G.G.) consortium, ALSPAC is well placed to contribute to a developing line of analyses concerned with the heritability of growth and development related traits. It is for this reason that we seek to enter summary results from available ALSPAC genomewide tests of association with birth weight, gestational age and related traits into the growing meta-analysis for these measurements. As stand alone studies, analysis of these traits in ALSPAC and the National Finnish birth cohort have not revealed sufficiently strong associations to yield statistically robust findings. Consequently efforts to examine the genetics architecture of these traits will require extensive meta-analysis, a process we wish to involve ALSPAC in.
B769 - Levels determinants and consequences of variation in ovarian and testicular function using Anti-Mllerian hormone - 16/01/2009
We request permission to use available funds to complete assays of Anti-Mullerian hormone (AMH) on the serum residuals that are currently held in Glasgow from samples taken at the 15+ clinic. An NIH funded grant (PI: DA Lawlor) provided funds for fasting glucose, insulin and lipids to be completed on a predicted 7000 samples at the 15+ clinic. Blood samples from this clinic were only available on ~3500 samples and relevant assays are now near complete on these. Because a smaller number of samples were assayed funds are available to complete AMH assays on these 3500; and sufficient serum for these assays is currently available in Professor Sattar's laboratory in Glasgow. AMH assays would be relevant to the NIH grant application since we will use these to examine developmental origins of ovarian and testicular function which are in turn related to vascular and metabolic health outcomes.
We would like to address the following objectives in relation to AMH:
a. Describe the distribution of AMH in contemporary males and females at mean age 15
b. Determine the association of parental smoking in pregnancy; maternal weight gain in pregnancy; blood pressure change in pregnancy; gestational diabetes/glycosuria in pregnancy and parental smoking whilst breast feeding (in those offspring who were breastfed) with offspring AMH levels at mean age 15
c. Determine the prospective associations of offspring smoking, fat mass and change in fat mass, growth trajectories from birth to age 15, age at menarche (females) with AMH levels at mean age 15
d. With available data (current 3000 or larger if grants funded) complete a genome-wide association study with AMH (In collaboration with David Evans & Nic Timpson) of AMH levels
e. Examine the cross-sectional associations of AMH with glucose, insulin and lipids at age 15.
Background
AMH and ovarian and testicular function
Anti-Mullerian hormone (AMH, Mullerian-inhibiting substance) is a member of the transforming-growth factor-beta family. AMH has the primary role of regression of the Mullerian duct in the male fetus during early testis differentiation. However, expression of AMH persists after completion of the reproductive duct system in males, and furthermore commences expression in females at this time, in whom it is produced by ovarian granulosa cells from early fetal life[1]. Although AMH is initially observed in granulosa cells of primary follicles, maximal expression occurs in preantral and small antral follicles[2, 3]. AMH expression declines as antral follicles increase in size, with nominal expression restricted to the granulosa cells of the cumulus[3]. This loss of AMH expression during the follicle stimulating hormone (FSH)-dependent final stages of follicular growth, and the lack of expression by atretic follicles[4], suggests that basal levels of AMH may more accurately reflect the total developing follicular cohort and consequently potential ovarian response to FSH. The clinical utility of this, and a demonstration of the likely causal signficance of AMH as a measure of ovarian function, is that AMH is strongly associated with oocyte yield, clinical pregnancy and live birth in IVF cycles[4-7]. It is also a sensitive measure of the gonadotoxic effect of differential chemotherapy regimens and falls rapidly after toxic stimuli[8-12]. It is elevated in polycystic ovarian syndrome, a condition associated with increased preantral follicles[13-18]. Lastly, it can indicate the timing of the menopause transition approximately 5 years prior to the sentinel event as determined by amenorrhoea and circulating follicle stimulating hormone levels[19, 20]. Importantly, AMH has also been shown to be relatively consistent across the menstrual cycle[21-23], consistent with its role reflecting the continuous, non-cyclic growth of small follicles in the ovary. AMH has therefore overtaken other markers and is now recognised as the optimal measure of follicular reserve in females[7, 24, 25].
AMH is also produced in males, and the ontogeny of AMH is similar across species[26, 27], in that circulating AMH produced by Sertoli cells remains high until the onset of puberty, when they progressively decrease, correlating with the stage of pubertal development. This decline in AMH is principally due to the inhibitory effect of intratesticular testosterone and meiotic cells on Sertoli cell AMH expression[28], and male AMH values decrease to female levels[29]. Male AMH therefore provides a unique handle on Sertoli cell number and function - the principal determinant of testicular germ cell number. Consistent with this subfertile men have a significantly lower AMH than controls[30], and that even the relatively mild insult of a varicocele is associated with a lower AMH in prepubertal, pubertal and adult males[30, 31].
Prenatal/developmental determinants of ovarian and testicular function
Gestational cigarette smoking is plausibly a strong determinant of ovariant and testicular function and likely to be related to AMH via intrauterine and lactation exposure. In female fetuses, smoking may have a direct toxic effect on the primordial follicle, leading to premature exhaustion of the follicular germ pool[32, 33]. In animal models impairment of fertility in the offspring following prenatal exposure to polycyclic aromatic hydrocarbons (in cigarette smoke) via the mother during pregnancy has been demonstrated. Histological analysis of ovarian tissue from the exposed offspring mice demonstrate a markedly reduced number of primordial follicles[34, 35], suggesting that a detrimental impact on ovarian reserve and follicular dynamics underlies this phenomenon. Notably, in mice models, the combination of pre-pregnancy and lactational exposure to polycyclic hydrocarbons was associated with a 70% reduction in primordial follicle number[36]. This loss of primordial follicles and primary follicles if applicable to humans has profound biological consequences, as it is generally accepted that mammals are born with a finite number of primordial follicles that are incapable of proliferating and replenishing, and it is this dogma which underlies the chronological decline in the fecundity of both natural[37-39] and stimulated ovarian cycles[40, 41] and the relatively static onset of the menopause.
Human studies examining the impact of maternal smoking on the ovarian reserve of the offspring have been limited[42, 43]. A small epidemiological study of 230 women with offspring recall of maternal smoking status during the index pregnancy demonstrated a reduced cumulative conception rate[42]. This association was robust to adjustment with frequency of intercourse, the offspring's age and own smoking status and childhood exposure. Prenatal exposure to maternal smoking and reduced fecundability in the offspring was also observed in a recall study of 663 women from Minnesota[43]. Analysis of time to pregnancy in 1653 female twins also demonstrated a reduced fecundability in the exposed female offspring[44]. In contrast for offspring exposed during childhood to parental smoking an increased fecundability in the offspring was observed in both of these studies[43]. Importantly this apparently conflicting data regarding the timing of exposure is dependent on offspring recall of parental smoking status and has not examined differential smoking status across gestation, lactation and childhood and has no information regarding dose-dependent effects. With the prospective data in ALSPAC we will be able to examine the association of smoking in pregnancy, during infancy (and lactation where relevant) and childhood on AMH levels an index of ovarian reserve (see above) and we will be able to compare associations with paternal smoking to establish whether maternal associations are likely to be acting through intrauterine mechanisms.
With respect to males maternal cigarette smoking during gestation has been increasingly associated with rising incidences of cryptorchidism and hypospadias and reductions in testis size, sperm counts/quality, and fertility[45-47]. Thus, we hypothesise that maternal smoking during pregnancy and lactation will also be related to reduced AMH levels in males as well as females.
In both males and females there is epidemiological evidence of an association between obesity, metabolic parameters and fertility and other reproductive outcomes. These characteristics also cluster within families, with intergenerational associations. Whilst AMH levels have been assessed in prepubertal offspring of mothers with PCOS (and shown to be elevated in comparison to similar aged offspring of women without PCOS[14], to our knowledge no one has previously examined the association of maternal obesity, weight gain and metabolic/ vascular characteristics during pregnany with offspring AMH levels
Genetic determinants of AMH
Many reproductive characteristics and diseases have high levels of heritability including age at menarche (50-70%; [48]), age at menopause (~ 50%;[49, 50]) and PCOS (~60% [51]). Analysis of 359 women with PCOS, demonstrated an association between circulating AMH levels and three SNPs of the ACVR1 gene which encodes the common ALK2 component of the heteromeric AMH receptor complex in an allele dose manner[52]. In contrast AMH was not associated with SNPs in either the AMH gene or the specific AMH type II receptor part of the heteromer, despite biological effects when expressed in cell lines[53]. We hypothesise that in a general population a number of common variants will have modest associations with AMH levels. In particular given that AMH and follicular function are linked to metabolic derangements, we will examine common variants of genes, regulating metabolic function and adiposity.
Associations of AMH with vascular and metabolic traits
The relationship reproductive health with vascular and metabolic traits, and specifically the association of PCOS with insulin resistance and reduced insulin secretion would predict associations of AMH with glucose, insulin and lipid levels.
Methods
AMH will be assayed on existing ALSPAC samples from 15+ at Professor Naveed Sattar's laboratory. The AMH assay used will be the commercial ELISA kit provided by DSL (Webster, Texas, USA). This kit is in routine use in our laboratories[5, 7]. Current inter and intra-assay CVs in our laboratory are 3.0% and 2.6% respectively. The Glasgow laboratory adheres to UK external quality control for all parameters and is Clinical Pathology Accreditation (CPA) accredited.
For objectives a-c and e relevant datasets will be compiled by DA Lawlor and standard linear / logistic regression models used in analyses. Sensitivity tests of possible non-paternity will be used when comparing maternal and paternal exposures with offspring AMH levels.
For objective d, data management and analyses will be undertaken by Dave Evans & Nic Timpson from MRC CAiTE, University of Bristol.
References
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2. Laven JS, Mulders AG, Visser JA, Themmen AP, De Jong FH, Fauser BC. Anti-Mullerian hormone serum concentrations in normoovulatory and anovulatory women of reproductive age. J Clin Endocrinol Metab. 2004 Jan;89(1):318-23.
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4. Ebner T, Sommergruber M, Moser M, Shebl O, Schreier-Lechner E, Tews G. Basal level of anti-Mullerian hormone is associated with oocyte quality in stimulated cycles. Hum Reprod. 2006 Aug;21(8):2022-6.
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6. Fanchin R, Schonauer LM, Righini C, Guibourdenche J, Frydman R, Taieb J. Serum anti-Mullerian hormone is more strongly related to ovarian follicular status than serum inhibin B, estradiol, FSH and LH on day 3. Hum Reprod. 2003 Feb;18(2):323-7.
7. Nelson SM, Yates RW, Lyall H, Jamieson M, Traynor I, Gaudoin M, et al. Anti-Mullerian hormone-based approach to controlled ovarian stimulation for assisted conception. Hum Reprod. 2009 January 10, 2009:den480.
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12. van Beek RD, van den Heuvel-Eibrink MM, Laven JS, de Jong FH, Themmen AP, Hakvoort-Cammel FG, et al. Anti-Mullerian hormone is a sensitive serum marker for gonadal function in women treated for Hodgkin's lymphoma during childhood. J Clin Endocrinol Metab. 2007 Oct;92(10):3869-74.
13. Chen MJ, Yang WS, Chen CL, Wu MY, Yang YS, Ho HN. The relationship between anti-Mullerian hormone, androgen and insulin resistance on the number of antral follicles in women with polycystic ovary syndrome. Hum Reprod. 2008 Apr;23(4):952-7.
14. Crisosto N, Codner E, Maliqueo M, Echiburu B, Sanchez F, Cassorla F, et al. Anti-Mullerian hormone levels in peripubertal daughters of women with polycystic ovary syndrome. J Clin Endocrinol Metab. 2007 Jul;92(7):2739-43.
15. El-Halawaty S, Rizk A, Kamal M, Aboulhassan M, Al-Sawah H, Noah O, et al. Clinical significance of serum concentration of anti-Mullerian hormone in obese women with polycystic ovary syndrome. Reprod Biomed Online. 2007 Nov;15(5):495-9.
16. Fleming R, Deshpande N, Traynor I, Yates RW. Dynamics of FSH-induced follicular growth in subfertile women: relationship with age, insulin resistance, oocyte yield and anti-Mullerian hormone. Hum Reprod. 2006 Jun;21(6):1436-41.
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B764 - Investigating the role of the HNF4A T130I variant in fetal growth - 13/01/2009
We wish to use ALSPAC as a replication study to investigate the role of the HNF4A T130I variant (rs1800961) in fetal growth and intermediate traits related to type 2 diabetes (T2D).
The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study is a multi-centre study of 25,000 mothers and their babies, which demonstrated a continuous relationship between maternal glucose and measures of birth size and fetal adiposity (1). A genetic association study of 1536 SNPs in ~80 candidate loci previously implicated in insulin secretion/sensitivity, has been carried out in a subset of HAPO samples to investigate associations with maternal glycemia at ~28 weeks gestation and offspring size at birth. Included in the study were 3828 mothers of European (Belfast and Manchester, UK, and Brisbane and Newcastle, Australia) and 1813 mothers of Asian (Bangkok, Thailand) ancestry and their offspring.
Among the top signals from the analysis was rs1800961, which encodes a Thrgreater than Ile amino acid change in exon 4 of HNF4A. This was strongly associated with increased fetal head circumference (0.5cm [95%CI: 0.3-0.7] per maternal risk (A) allele; P=1.2x10-7) in those of European descent. The maternal risk allele was also more weakly associated with 1-hour glucose from OGTT (4.3mg/dL [95%CI: 0.5-7.9]; P=0.03), birth length (0.7cm [95%CI: 0.2-1.1]; P=0.003), birth weight (52.6g [95%CI: -8.0-113.3]; P=0.09), and sum of skinfolds (0.3cm [95%CI: -0.1-0.6]; P=0.13). This same risk allele in the fetal genome was weakly associated with cord C-peptide (0.1ug/dL [95%CI: 0.01-0.22]; P=0.03), and head circumference (0.2cm [95%CI: -0.1-0.4]; P=0.08). The same trends were observed among the Thai (Pgreater than 0.05).
We are interested to seek replication of these results in ALSPAC for the following three reasons:
1. Statistical evidence: the maternal genotype-head circumference association survives Bonferroni correction for multiple testing, while multiple other traits show associations at Pless than 0.1 in a consistent direction
2. The SNP is has been recently associated with HDL-cholesterol levels with evidence that exceeds the generally accepted criteria for "genome-wide significance" (Pless than 5x10-8) (2). This evidence that the SNP is marking a real biological function increases the prior odds that it will be associated with fetal growth. The minor A allele, associated with increased fetal head circumference in the HAPO study, predisposes to lower HDL levels in the general population.
3. Carriers of rare diabetes-causing mutations in HNF4A experience greatly increased fetal growth (3). The associations in HAPO of the fetal allele with raised C-peptide and head circumference are consistent with this. Also, in line with the genome-wide lipid data, HDL levels are lower in individuals with HNF4A mutations (4).
Power
The SNP is relatively rare (MAF=4% in Europeans and 2% in Thai). Assuming 7000 ALSPAC mothers in the analysis, we estimate that we will have greater than 99% power to detect a change in head circumference of the magnitude seen in HAPO at Pless than 0.05. To detect a change in birth weight of 50g per allele, we will have 64% power. Even if the associations observed in HAPO represent true underlying effects on fetal growth, it is likely that the "Winner's Curse" has led to an overestimation of effect sizes. Therefore, it will be important to meta-analyse data from the individual HAPO study sites, along with ALSPAC. We will also genotype the SNP in samples from the Exeter family study (950 population based parent-newborn trios), and we will potentially be able to add further samples from the HAPO study (~1500 further Caucasian mother-offspring pairs; 1250 African-Caribbean; 800 Hispanic). We hypothesize that real genetic associations will be consistent across all of these studies - i.e. even if individually studies show only nominal significance, or even P values greater than 0.05, a meta-analysis of all studies will provide highly significant results.
We therefore propose to analyse the polymorphism in ALSPAC to test the following hypotheses:
1. Fetal genotype and maternal genotype are associated with measures of fetal growth, including head circumference, weight and length at birth.
2. Offspring genotype is associated with diabetes-related traits in childhood including fasting insulin, fasting glucose and insulin secretion (in the subset of offspring with OGTT data), triglycerides, HDL, LDL and total cholesterol, anthropometric measures including BMI, lean/fat body mass, WHR, waist circumference, skin folds where available.
To do this we would like to genotype (at Kbiosciences) all ~20,000 ALSPAC samples. We will need the following phenotypes to test our hypotheses (a detailed list is in the next section):
1. Birth weight, length and head circumference
2. Covariates of birth weight to check if genotype is acting through them: gestational age, maternal age, maternal BMI, smoking , parity, twin status to exclude non-singletons, ethnicity as genotype frequency may alter with ethnic origin and confound analyses.
4. Type 2 diabetes-related intermediate traits including fasting insulin, fasting glucose and insulin secretion (in the subset of offspring with OGTT data), triglycerides, HDL, LDL and total cholesterol, anthropometric measures including BMI, lean/fat body mass, WHR, waist circumference, skin folds where available.
REFERENCES
1. Metzger BE, Lowe LP, Dyer AR, Trimble ER, Chaovarindr U, Coustan DR, Hadden DR, McCance DR, Hod M, McIntyre HD, Oats JJ, Persson B, Rogers MS, Sacks DA: Hyperglycemia and adverse pregnancy outcomes. N Engl J Med 358:1991-2002, 2008
2. Kathiresan S, Willer CJ, Peloso GM, Demissie S, Musunuru K, Schadt EE, Kaplan L, Bennett D, Li Y, Tanaka T, Voight BF, Bonnycastle LL, Jackson AU, Crawford G, Surti A, Guiducci C, Burtt NP, Parish S, Clarke R, Zelenika D, Kubalanza KA, Morken MA, Scott LJ, Stringham HM, Galan P, Swift AJ, Kuusisto J, Bergman RN, Sundvall J, Laakso M, Ferrucci L, Scheet P, Sanna S, Uda M, Yang Q, Lunetta KL, Dupuis J, de Bakker PI, O'Donnell CJ, Chambers JC, Kooner JS, Hercberg S, Meneton P, Lakatta EG, Scuteri A, Schlessinger D, Tuomilehto J, Collins FS, Groop L, Altshuler D, Collins R, Lathrop GM, Melander O, Salomaa V, Peltonen L, Orho-Melander M, Ordovas JM, Boehnke M, Abecasis GR, Mohlke KL, Cupples LA: Common variants at 30 loci contribute to polygenic dyslipidemia. Nat Genet 41:56-65, 2009
3. Pearson ER, Boj SF, Steele AM, Barrett T, Stals K, Shield JP, Ellard S, Ferrer J, Hattersley AT: Macrosomia and hyperinsulinaemic hypoglycaemia in patients with heterozygous mutations in the HNF4A gene. PLoS Med 4:e118, 2007
4. Murphy R, Ellard S, Hattersley AT: Clinical implications of a molecular genetic classification of monogenic beta-cell diabetes. Nat Clin Pract Endocrinol Metab 4:200-213, 2008.
B758 - Intrauterine origins of autism risk placental analysis of infection and hypoxia - 09/01/2009
Hypothesis 1. Autism risk is associated with exposure to intrauterine cytokines and/or hypoxia.
Autism and other neuropsychiatric risks have been linked to intrauterine exposures to cytokines and/or hypoxia. These studies are limited in that they have been forced to rely upon retrospective cohorts, maternal serum samples, maternal medical history, etc., each of which is problematic in terms of bias (true peer "control" sample), ascertainment (retrospective assessment of maternal gestational illness), or true measure of fetal exposure (maternal serum cytokines do not necessarily imply fetal cytokinemia).
The ALSPAC cohort will allow us to avoid most of those pitfalls, in a nested case-control study that will use both standard histopathologists' definitions and image analysis, to determine the presence and severity of
* acute inflammation (most commonly a marker of intraamniotic infection),
* chronic placental inflammation (with a differential diagnosis generally considered to be congenital viral infection or maternal attack against the semi-allogeneic fetoplacental unit), and
* the villous effects of uteroplacental malperfusion (villous fibrosis, excess syncytial basophilia and knotting, infarcts, abruption, generally reflecting reduced fetal oxygenation secondary to the abnormal maternal perfusion of the placenta and/or damage to the placenta).
Hematoxylin and eosin stained slides (and special stains as indicated) will be scored by a team of 3 trained and expert pathologists, and the digitized slides will be evaluated using sets of segmentation and quantification algorithms developed to measure inflammation and hypoxia.These semiquantitative (pathologist') and continuous (image analysis) variables will be correlated with case-control status, with adjustment for gender, gestational age and birth weight at delivery using structual equation models in which the placental histology features are considered to be indicators of underlying latent variables (e.g., maternal acute inflammatory responses, fetal acute inflammatory responses, maternal malperfusion). The model including all
All cases of autism identified in ALSPAC (n=56) will be included in this nested case-control study. We will select four controls for each case to maximize statistical power of the comparisons. The gain in statistical power with the use of additional control subjects is negligible. The large size of the ALSPAC cohort allows us to match on a few key variables that may be differentially distributed among the cases. We propose to match on infant sex and gestational age (=/- 1 week ideally, 2 weeks if necessary). Prematurity is not a major risk factor for autism so we expect matching on gestational age to be feasible.
2. Placental vascular branching is a biomarker for Autism.
Autism is a disorder of abnormal neuronal connectivity and, by extension, abnormal neuronal dendritic branching. The placenta is an organ that is architecturally little more than a thin tissue sheath covering a vascular tree. It is uniquely dependent on coordinated and accurate paternal gene expression, and its growth is regulated by gene families that regulate events that may be key to the connectivity issues described in autism. We hypothesize that the vascular architecture of the placenta is a proxy for aspects of neuronal differentiation, elongation and navigation that are germane to the genesis of autism risk. Thus autism risk will have parallel placental findings of altered villous and vascular branching.
Neurons and the Vasculature: Shared Pathways for Outgrowth, Proliferation and Branching Diversity. Placental blood vessels provide oxygen and nutrients to and remove metabolic products from the embryo/fetus. It has been recognized that the signals and guiding principles to differentiate, elongate and navigate blood vessels towards their destinations are analogous to those in neuronal development. Vascular endothelial growth factor (VEGF) promotes vascularization of the placenta as well as neuronal differentiation. Similarly, a number of factors promote endothelial proliferation and angiogenesis; moreover, their cross-talk-and in particular their defective cross talk-may be at the root of a wide range of both vascular/ neurological and placental diseases .
Antiangiogenesis and Autism: Thalidomide and Valproate. Thalidomide and valproate exposures in early pregnancy are recognized risk factors for autism. Animal models exposed in utero to valproate demonstrate neuroanatomical changes in the brainstem and cerebellum that are comparable to those in brains from children with autism. Both of these drugs are antiangiogenic as well as teratogenic. Mechanisms of such damage involve disruption to vascular growth factors, i.e., VEGF and placental growth factor (PlGF) and their associated signal transduction pathways. Note, VEGF and PlGF are produced and released by the placenta.
Hypothesis: Placental Vascular Branching is an Indicator of Normal Fetal Neuronal Connectivity. Autism is a disorder of abnormal neuronal connectivity and, by extension, abnormal neuronal dendritic branching. The placenta is an organ that is architecturally little more than a thin tissue sheath covering a vascular tree. It is uniquely dependent on coordinated and accurate paternal gene expression, and its growth is regulated by gene families that regulate events that may be key to the connectivity issues described in autism. We hypothesize that the vascular architecture of the placenta is a proxy for aspects of neuronal differentiation, elongation and navigation that are germane to the genesis of autism risk. Thus autism risk will have parallel placental findings of altered villous and vascular branching.
Measuring Placental Vascular Abnormality. The placenta is accessible (delivered with each baby born), and can be measured reliably. In a series of papers, we have developed novel methods for the study of the placental vascular arborization. We have introduced a dynamic model of the placental vascular growth based on a well-studied fractal random growth process (DLA). The model has allowed us to associate an abnormal morphology of the placenta with the abnormal vascular branching and connectivity. The standard marker of the branching density of a fractal tree is a version of a fractal dimension. While mathematically elegant, it is difficult to quantify in a practical study. We proposed a new idea, relating the placental vascular branching structure with a metabolic scaling exponent. This quantity is easy to measure as a ratio of logarithms of the fetal birth weight and the placental weight, and is a biologically relevant version of the fractal dimension of the vasculature. Our studies have demonstrated an association of the scaling exponent with the known factors affecting the normal vascular development.
Preliminary Findings on a Female-Specific Risk Factor for Autism: Advanced Paternal Age. Autism and Autism Spectrum Disorders have a strong genetic component, and a predilection for males. Recently, a risk factor for autism, advanced paternal age, was demonstrated to have an effect confined to female offspring, who inherit their second X-chromosome from their fathers [18]. The operative hypothesis is that the X-chromosome, which contains many genes associated with cognition and intelligence, may acquire either mutations or epigenetic alterations over the father's lifespan that then alter those gene's expression in his daughters. We have recently identified a female-specific negative effect of advanced paternal age on birth weight in the National Collaborative Perinatal Project, a well studied national cohort with over 24,000 cases with placental data. The placentas were thinner in this case, indicating a less arborized vascular tree.
Methods of the Proposed Research.
a. Placental Processing: Placentas will be processed according to protocols that have been reviewed and agreed to by the Pathology Department University of Bristol Hospital. Specific features include:
1. Digital photography of the chorionic surface and of slices of the placental disk.
2. Tissue sampling to include:
2 cross sections of the umbilical cord
1 membrane roll
4 samples of grossly normal placenta obtained from each placental quadrant
2 "functional units" (2.5 cm square full thickness regions with a terminal chorionic surface vessel)
Digital photographs will be uploaded to the Placental Analytics FTP site for analysis. Tissue samples will be processed to wax blocks. The blocks will be shipped to Placental Analytics, LLC for slide preparation.
Data extracted from the digital photographs and copies of the files of all digitized histology slides prepared from the placental tissue samples will be returned to ALSPAC as they are generated throughout the course of the study.
Tissue blocks will be retained by Placental Analytics, LLC until completion of the study at which point they will be returned to ALSPAC.
Placental Vascular Analyses: A key to our analysis of the placental vascular branching structure is the connection between the arborization of the vascular tree and the metabolic scaling exponent (a biologically relevant fractal dimension), as well as the morphological factors, such as the shape and the size of the placenta. Using the DLA model of placental angiogenesis, we can connect the variability in the placental shape with a perturbation in the placental vascular architecture. Fourier analysis of the two-dimensional images of the chorionic plate can be used to reliably identify such perturbations which appear early in gestation, and are hypothesized to be connected to Autism risk. An early reduction of the placental angiogenesis is also related to a larger value of the metabolic scaling exponent - a quantity which is particularly easy to measure at the time of delivery, with implications for an early diagnostic of the related Autism risk factors.
We have begun the analysis of 3-dimensional placental shapes, beginning with the study of the thickness and variability of slices perpendicular to the chorionic plate. The thickness of the slices, in particular, is associated with the vascular density. Our preliminary findings show that for female babies, the average thickness is adversely affected by the advanced paternal age, which is a known Autism risk factor. The variability of thickness is also associated with the suppressed angiogenesis in the DLA model [16]. We have also initiated the study of the skeletonized structure of the placental vasculature both for DLA models (with the skeletons of vascular trees traced automatically) and for digital photographs of the chorionic surfaces (with manually traced skeletons). We have developed measures of average density of the large and medium blood vessels in the placental surface, which complement the techniques described above, with similar results. We plan to further this approach by developing automated digital recognition of the large-scale branching structure in the chorionic plate surfaces.
B759 - Behavioural and psychiatric side effects of medication use in childhood - 08/01/2009
The issue of chronic medication use during childhood is sometimes controversial, particularly in regard to psychotropic medication (Lancet, 2008). Little is known about the long-term effects of psychotropic drug use in children and evidence for efficacy can be scant. One of the commonest chronic medications prescribed for children are inhaled corticosteroids which are the mainstay of preventive treatment for asthma. It is estimated that between 4- 9% of children under 12 in the UK are prescribed medication for asthma (Turner et al, 2009). Many children remain on inappropriately high doses of steroids for longer than is necessary (Turner et al, 2009). Although there is awareness of adverse effects of steroids such as growth retardation, adrenal insufficiency and ocular and skin effects (Lipworth , 1999; Covar et al, 2000) there appears to be little awareness of the potential adverse effects of these medications on children's mental health.
Clinically, from our work in liaison psychiatry, it is evident that steroid treatment commonly results in psychotic-type symptoms in the general hospital setting. Case studies on adult patients have demonstrated a wide range of behavioural and psychiatric side effects resulting from corticosteroid treatment, including disturbances of mood, cognition, aggression, hyperactivity and psychosis (Warrington and Bostwick, 2006). However, there is little data available for paediatric populations. One randomised controlled trial on the efficacy of high dose corticosteroids in the treatment of acute lymphoblastic leukaemia in children has reported on psychiatric side effects. These included severe depression, violence towards self and others, mood swings and lability, and psychosis (Mitchell et al., 2005). In fact, "behavioural toxicity" was the most significant side effect recorded in the study. It is not known whether psychotropic effects would be seen with low-dose corticosteroids (such as the normal doses for inhaled steroids). To our knowledge, no research to date has been conducted to formally assess psychiatric symptomatology among children using corticosteroid medication. As a result, the true side effect profile of this medication is unknown.
Our application to ALSPAC is prompted by an intriguing (unpublished) finding from analysis of our Challenging Times study data (Lynch et al., 2004; Kelleher et al., 2008) which showed a significant association between a diagnosis of asthma and psychotic-type symptoms in children aged 12-15 years of age. Fourteen percent (n=29) of the adolescents interviewed had a history of asthma. 58.6% of these participants had been treated with corticosteroid medication in the course of their illness. Further analyses revealed that the adolescents who had received corticosteroid therapy for their asthma were significantly more likely to have experienced psychotic symptoms than the adolescents who had a history of asthma but no corticosteroid use. The numbers in our study are small, however, and the ALSPAC data would allow more careful analysis of this important research question. We would like to examine other psychiatric symptoms also as potential adverse effects of steroids.
We are also interested in adverse side effects of stimulant medication use in children, in particular the possible association between stimulant use and psychotic-type symptoms. Stimulant medication has been commonly used for treatment of Attention Deficit Hyperactivity Disorder (ADHD) although concerns are increasingly being expressed about its use as a first line treatment (Kendall et al, 2008) There are few studies that have examined the behavioural and psychiatric side effects of stimulant medication use in children (Barkley et al., 1990). The few data available on methylphenidate have shown side effects including depression, irritability, violent behaviour and mania (Schachar et al., 1997). Psychotic reactions have also been documented in the literature (Cherland and Fitzpatrick, 1999), but this has been noted as a result of obvious psychotic disturbance and not a result of systematic investigation of psychotic symptoms. It, thus, likely represents an underestimation of the true side effect profile of stimulant medication.
In order to address our research questions, the following psychological variables would be needed for all time points available:
Exposure information:
- Medication use in childhood and adolescence
- Medical and psychiatric illness diagnosed in childhood and adolescence
Principal outcome measure:
- Psychotic symptoms: PLIKS age 12 (interview) , PLIKS (questionnaires) ages 13, 14, 15, 16
Secondary outcome measures:
- Other Psychopathology: DAWBA (ages 7,10,13, 15); SDQ (age 4, 6,8,9,11,13); MFQ (ages 9,10,11,12,13); Antisocial behaviour (ages 8,10, 12), borderline personality interview (age 12).
- Measures of cognitive function and educational attainment:
IQ test scores (4,8,15); Attention measures (age 8,11); Exam scores SATS ages 7,11,14, GCSEs age 16
Possible Confounders:
- SES; gender, family history of psychiatric disorder
Analysis:
Analysis will be performed in STATA (v9). We will study repeated measures of psychopathology in relation to commencement (and discontinuation) of medication. Our main outcome of interest is psychotic-type symptoms but we will also measure the changes in other psychopathology and cognitive ability in relation to medication use. We will take account of possible confounders such as social class, gender and family history of psychiatric illness.
References:
Barkley RA, McMurray MB, Edelbrock CS, Robbins K (1990) Side effects of methylphenidate in children with attention deficit hyperactivity disorder: a systemic, placebo-controlled evaluation. Pediatrics, 86 (2): 184 - 192
Cherland E and Fitzpatrick R (1999) Psychotic side effects of psychostimulants: a 5-year review. Canadian Journal of Psychiatry, 44 (8): 811 - 813
Covar RA, Leung DY, McCormack D et al (2000) Risk factors associated with glucocorticosteroid induced adverse effects in children with severe asthma. J Allergy clin Immunol, 106: 651-9
Kelleher I, Harley M, Lynch F, Arseneault L, Fitzpatrick C and Cannon M (2008) Associations between childhood trauma, bullying and psychotic symptoms among a school-based adolescent sample. British Journal of Psychiatry, 193: 378 - 382
Kendall T, Taylor E, Perez A, Taylor C. (2008) Diagnosis and management of ADHD: summary of NICE guidance. 337: a1239
Lancet editorial (2008) Chidren and psychiatric drugs: disillusion and opportunity. 372:1194
Lipworth BJ. (1999) Systemic adverse effects of inhaled corticosteroid therapy: a systematic review and meta-analysis. Arch Intern Med 159:941-4.
Lynch F, Mills M, Daly I, Fitzpatrick C (2004) Challenging Times: a study to detect Irish adolescents at risk of psychiatric disorders and suicidal ideation. J Adolesc, 27: 441 - 451
Mitchell CD, Richards SM, Kinsey SE, Lilleyman J, Vora A, Eden TOB (2005) Benefit of dexamethasone compared with prednisolone for childhood acute lymphoblastic leukaemia: results of the UK Medical Research Council ALL97 controlled trial. British Journal fo Haematology, 129: 734 - 745.
Panico L, Bartely M, Marmot M, Nazroo JY, Sacker A, Kelly YJ. (2007) Ethinic variation in childhood asthma: findings from the Millenium cohort. Int J Epid 36:1093-1102.
Schachar RJ, Tannock R,Cunningham C, Corkum PV (1997) Behavioural, situational and temporal effects of treatment of ADHD with methylphenidate. Journal of the American Academy of Child and Adolescent Psychiatry, 36 (6): 754-763
Turner S, Thomas M, von Ziegenweidt J, Price D (2009) Prescribing trends in asthma: a longitudinal study, Arch Dis Child; 94:16-22
Warrington TP and Bostwick JM (2006) Psychiatric adverse effects of corticosteroids. Mayo Clin Proc, 81 (10): 1361 - 1367.