Proposal summaries
B591 - Identifying psychosocial risk factors associated with the developmental outcomes of children with and without autism - 29/11/2007
The overarching aim of this study is to assess the extent to which individual differences in a variety of early psychosocial measures taken in the ALSPAC cohort predict individual differences in outcome 10 to 15 years later. To achieve this aim, this study will use a case-control design, where a group of individuals with autism (cases) will be compared with a group of individuals without autism (controls). Nonautistic adolescents matched for childhood IQ, sex, birth order, and parental social class will be selected as control individuals. To begin, we will determine the developmental outcomes of case and control individuals, including current autistic symptomatology, social and communicative competence, cognitive functioning, academic attainment, and mental health status. We will then examine whether early psychosocial predictors are independently associated with multiple outcomes, and whether the same variables are predictive of outcomes (and to the same extent) for adolescents with and without autism.
Suitable families will be contacted and invited to take part in the follow-up study. Only families who have not actively declined participation previously will be eligible for participation in this study. The extent of attrition is expected to be reasonably high given the amount of time for which the longitudinal study has been running; therefore, we expect to see approximately 40-50 individuals with autism and 40-50 matched controls. Initially, we will interview case and control parents via telephone to obtain information about developmental history (Social Communication Questionnaire; Rutter et ao., 2003) and basic demographic factors. The interviewer(s) will be blind to the case/control status of the participants. We will then invite participants and their primary caregiver to come in to the University for interviews and assessments. Outcome measures will include (1) extent and nature of autistic symptomatology (as indexed by the Autism Diagnostic Interview - Revised [Lord et al., 1994] and the Autism Diagnostic Observation Schedules [Lord et al., 2000]); (2) specific cognitive skills (as measured by a battery of tasks tapping social cognition, executive function, and visuospatial ability); (3) social adaptation (as measured by the subject and informant versions of the Socio-emotional Functioning Intervew; Rutter et al., 1988); (4) IQ (as assessed by the full form of the Wechsler Adult Scales of Intelligence - Third Edition; Wechsler, 1999); (5) academic functioning (as indexed by measures of maths, reading, and phonological skills); and (6) psychiatric functioning (particularly anxiety and depression). Outcome variables will be assessed blind to predictor variables.
Initial analyses will be performed by comparing cases and controls on key outcome variables. Data will be linked with retrospective data on key psychosocial variables (deprivation, family size, temperament, attachment behaviour, parenting style, behaviour/emotions, social relationships) as well as other child variables (autistic symptoms, childhood IQ, language ability) for individual participants. Multiple regression models will be used to predict outcome, with 'caseness' (i.e., autism, nonautism) entered as an additional independent variable. For each outcome variable, we will determine (1) the amount of total variance explained, (2) the independent and separate contributions of each predictor variable, (3) and the interaction term (caseness by predictor variable). If the interaction term turns out to be significant, then this would suggest that the link between the predictor and outcome variable differs according to whether or not the individual has an autism spectrum condition.
This study should advance our knowledge of the sorts of factors predictive of individual children's developmental outcomes. This knowledge is not only critical for achieving a complete aetiological understanding of the condition, but also will highlight which factors play a role in maximise children's potential as they 'move on up' into adulthood (National Autistic Society, 2007).
A list of specific ALSPAC variables is attached.
B590 - The intergenerational transmission of violence and pro-violence attitudes in the ALSPAC cohort - 28/11/2007
This study will examine the nature of dating violence as reported by male and female adolescents and determine the applicability of the intergenerational hypothesis in each case. In addition, the study will examine the relationship between early socialization and the development of pro-violence attitudes.
There are three aims of this project:
1.The first is to provide a descriptive analysis of the incidence of dating violence within the ALSPAC cohort. This will include a gender based analysis of the use and receipt of violence within dating relationships as well as the young people's understanding of these behaviours and help seeking behaviours associated with the experience of these behaviours.
2. The second aim is to determine the extent to which the experience of violence within dating relationships (as both perpetrator and victim) reflects an intergenerational pattern. This will be examined in relation to the young person's possible exposure to inter-parental violence, harsh parental discipline and parental maltreatment, controlling for additional family adversity exposure and previous involvement in bullying and antisocial behaviour. Should the data permit, a gender based analysis of these issues will be conducted.
3. The final aim is to determine the extent to which pro-violence attitudes reflect earlier exposure to inter-parental violence, harsh parental discipline, parental maltreatment, after controlling for additional family adversity exposure and previous involvement in bullying, antisocial behaviour and dating violence.
As a consequence of this investigation at least three manuscripts will be written for submission in international peer reviewed journals. In addition, these preliminary investigations will provide the basis of continued research funding applications that will focus on examining potential mediators and moderators of any intergenerational effects wtihin a risk and resilience framework.
In order to fulfil these project aims, the following data is required:
Family Adversity Index (FAI) data with the maternal victimization variables isolated for separate analyses
Child Maltreatment Index - this will be derived from variables relating to maternal parenting practices.
Maternal reports of victimization
Paternal reports of victimization
Maternal parenting data
Paternal parenting data
Bullying involvement data
Dating violence data
Pro-violence attitude data
Details of the measures and observations are presented in table 1 (see attached).
B589 - The predictive validity of infant temperament on childhood mental health problems - 27/11/2007
Research Questions
1) Do temperamental characteristics up to the age of 3 years predict later mental health problems?
2) Which temperamental traits best predict psychiatric disorder at the age of 7 years?
3) Can temperamental characteristics in infancy (age 6 months) predict later psychiatric disorder?
Background
In recent years, there has been increasing interest in the early identification of and the development of interventions for infant mental health problems. It is unclear as to which children grow out of these difficulties and which might benefit from further monitoring and assessment by child health and educational professionals. In particular, we wish to investigate whether parent-identified temperamental traits up to the age of 3 years predict an independent diagnosis of psychiatric disorder at age 7 that also takes information from teachers into account?
Key Measures
Predictor: Temperament measures - the Carey scales at 6 and 24 months & EAS scale at 38 months
Outcomes: Child mental health - externalising and internalising problems as measured by the SDQ at later time points, parent and teacher DAWBAs, & Mood & Feelings Questionnaires.
Confounder variables: The analyses will control for key confounding factors including child gender and maternal mental health.
Analytical Approach: Following initial bivariate analyses, multivariable logistic regression analyses will assess the effect of temperament measures at each time point on the presence of any psychiatric disorder at age 7. Maternal EPDS will be included at each time point to cover rater factors. As sample attrition may be related to both the exposure and outcome, response status at follow-up will be related to baseline variables.
Concept Specific measure Person Source Time point(s)
Temperament Carey & EAS scale Mother Questionnaire Birth to 3 years
Mental Health SDQ Mother Questionnaire 47 months to 13 years
Mental Health SDQ Teacher Questionnaire 93-108 months
Mental Health DAWBA Mother &Teacher Questionnaire 7 years to 13 years
Mental Health MFQ Mother Questionnaire 9 years to 13 years
Maternal EPDS Mother Questionnaire Birth to 5 years Depression
B587 - Development of depression and smoking in adolescents - 27/11/2007
Applications are invited from suitably qualified psychology graduates to join a team investigating the development of depressive symptoms. The PhD will be undertaken in the Department of Community Based Medicine and will focus on examining the nature of the relationship between depressive symptoms and smoking.
Previous studies have found evidence for an association between depression and smoking in adolescence, but the nature and direction of the relationship is unclear. Some studies have found evidence that depressive symptoms precede the onset of smoking; others have found that smoking precedes depression, and some studies report a bi-directional relationship. The PhD student will have the opportunity to develop skills in statistical modelling of longitudinal data to model the developmental heterogeneity of depression and smoking from late childhood into adolescence and examine potential covariates including gender, behaviour and conduct problems, social adversities, stressful life events, and parent-child relationships.
The project will take advantage of the unique and extensive longitudinal data collected by ALSPAC, an ongoing longitudinal population-based study investigating a wide range of environmental and other influences on the health and development of children. Detailed information on the ALSPAC study is available on the web site: http://www.alspac.bris.ac.uk.
Data required:
Depression- Mood and feelings questionnaire (child and parent report) from 9-15 years.
Smoking- (child and parent report) from 8-15 years.
(we are aware that data from the 15/16 year questionnaire/clinic is not yet available)
Other possible data requirements: Behaviour and emotional problems- DAWBA, SDQ, antisocial behaviour questionnaire.
Social adversities and stressful life events.
Questions on parent-child relationships.
B586 - Role of rs17822931 in traits dependent on earwax colostrum or body odour and phenome scan - 22/11/2007
No outline received
B585 - Victimisation in childhood and borderline personality disorder in a non-clinical population of 11 year olds results from the ALSPAC birth cohort - 20/11/2007
The aim of the present study is to examine various victimization experiences (domestic, physical harshness) and peer victimization, and their association with BPD in a longitudinal study of a young general population sample with detailed assessment of traumatic events as well as BPD. The specific questions to be answered are: (1) What is the association between peer victimisation versus other traumatic victimisation in childhood and BPD at the of 11? (2) Is there a dose-response relationship between the number of victimisation events and the risk for BPD (3) Are the observed associations independent or mediated by other psychopathology?
B466 - EMMETT VIP - 14/11/2007
No outline received
B465 - Mattocks VIP - 14/11/2007
No outline received
B610 - Investigating the role of a novel fasting glucose varient in fetal growth - 13/11/2007
B582 - Breastfeeding and Childrens outcomes - 13/11/2007
We are applying to use ALSPAC data as part of a large project for which we will be requesting funding from the ESRC. This project will not focus solely on ALSPAC data, but will also use data from the Millennium Cohort Study (MCS) which has already been made available to us, and the Infant Feeding Survey (IFS). We envisage our project as comprising four sub-projects. Not all of these will make use of ALSPAC data; however. In the proposal below, we include a brief outline of those parts of the project which involve other data sets, as this provides useful context for the investigations which do use ALSPAC.
There is already an extensive literature on the effects of breastfeeding on a number of outcomes: allergy and asthma; developmental delay in children; childhood blood pressure, and many others. There is also a recognition that standard multivariate analytical techniques may overestimate the positive effects of breastfeeding, due to a mother's propensity to breastfeed being correlated with unobservable (or simply unobserved) factors which are themselves associated with favourable child's outcomes. This problem of endogeneity is likely to lead to the effects of breastfeeding being overestimated. This project aims to carry out a causal analysis of the effects of breastfeeding: that is, an analysis which, as far as possible, overcomes the effects of endogeneity.
The ideal data with which to undertake such a causal analysis of the effects of breastfeeding would arise from a large-scale randomised experiment on infant feeding. However, the ethical considerations involved make such an experiment almost inconceivable. In order to study this issue, therefore, researchers must exploit variation in infant feeding patterns arising from other factors. Here, we propose to use two distinct analytical techniques to examine the extent to which estimates of the effects of breastfeeding are biased if one does not account for the endogeneity of the decision to breastfeed; and to attempt to uncover the causal effect of breastfeeding. We propose four inter-related projects, the first two of which examine children's cognitive outcomes, the third of which examines mothers' mental health, and the last of which examines parents' time off work looking after sick children.
1. The effect of breastfeeding on children's cognitive skills, using an Instrumental Variables approach
This project will identify the causal effect of breastfeeding on children's cognitive development, using an instrumental variables approach. The project will use data from the MCS, and will employ as instrument an exogenous variation in breastfeeding rates determined by whether or not the hospital at which a mother gave birth subscribed to the Unicef Baby Friendly Initiative (BFI). Several studies show that breastfeeding rates (initiation and/or duration) are higher in Baby Friendly hospitals. The IV method relies on the assumption that BFI status is exogeous. We believe this is a reasonable assumption: although mothers in the UK are free to choose the hospital at which they want to give birth, in most cases they are restricted in this choice by travel distance.
2. The effect of breastfeeding on children's cognitive skills, using a Propensity Score Matching approach
This project will also examine the relationship between breastfeeding and children's cognitive skills - but it will use a different data set (ALSPAC) and a different analytical technique (Propensity Score Matching, or PSM). This technique is described by Dehejia and Wahba (2002) and others, and has been used extensively in economics to assess causal effects. Using this technique, the analyst generates two samples of individuals who have and who have not undergone a "treatment" (here, breastfeeding), matched on a wide range of characteristics, as well as by their estimated propensity to breastfeed. The difference in outcomes between the two matched groups provides an estimate of the causal effect of breastfeeding. ALSPAC lends itself well to PSM, containing a wealth of data on parents' attitudes to breastfeeding, their prior intentions to breastfeed, and events during and after birth which may affect whether children are eventually breastfed.
The outcome variables on which we propose to focus are as follows:
* Key Stage 1 SATs results (we would like to use KS2 SATs results as well, but understand these are not yet available
* Results of school entrance assessments from the SATs files
* Teacher assessments: the child's ability group (Year 6); the Year 4 maths test; and teacher ratings of children's ability in Year 3.
* Parents' assessments of their children's development - particularly their assessments of vocabulary and other language-related skills - from the parent-completed questionnaires at 15, 24 and 38 months.
3. Breastfeeding and mothers' mental health: A PSM approach
This section would use data from both ALSPAC and the MCS to examine the relationship between breastfeeding and mothers' mental health. Kendall-Tackett (2007) presents evidence that breastfeeding protects against post-natal depression via two mechanisms: reducing stress, and reducing inflammation. We propose to build on this by investigating the relationship between breastfeeding and maternal wellbeing, using the analytical techniques described above to control for the possible endogeneity of the decision to breastfeed, and to identify the causal relationships involved.
In ALSPAC, the outcome variables of interest would be:
* Crown-Crisp Experiential Scores from birth until 33 months, and subscales where available
* Edinburgh Post-Natal Depression Scores from birth until 33 months
* Other indicators of wellbeing and relationship to child (for example, J151, mum has felt unattached to study child, in the mother's questionnaire at 47 months).
4. Breastfeeding and mothers' work: a cost-benefit analysis
There is a considerable body of research looking at the return to work as a determinant of breastfeeding behaviour. Here, we propose to look at the relationship between breastfeeding and mothers' paid work, by allowing for causal effects in both directions. A mother's decision to breastfeed might influence the time at which she chooses to return to work, but recent research has shown that the length of the period of maternity leave may in turn affect decisions about initiation and duration of breastfeeding.
In addition, we propose to examine the effect of breastfeeding on the number of days parents take off work to look after sick children. Existing research shows that breastfed babies are at lower risk of a number of childhood illnesses; we propose to examine whether this translates to the parents of breastfed children taking less time off work to look after sick children. This is not an easy question to address, since data on this aspect are not available in all waves of ALSPAC. However, by combining data on hospital admissions, the number of illnesses (including ear infections and attacks of gastro-enteritis), and the amount of time parents have taken off work to look after children with ear and other general health problems (asked at 33 and 47 months), we may begin to make some informed assumptions about whether breastfeeding has economic benefits by reducing working parents' absenteeism rates and therefore is beneficial for employers as well as mothers and children.
B581 - Phenotypic effects from birth to adolescence of puttative causal genetic variants - 13/11/2007
No outline received
B583 - Replication attempt of a signal observed in a genome-wide association study for childhood obesity - 09/11/2007
No outline received
B579 - Interaction of FLG and SPINK5 polymorphisms in exczema in children - 09/11/2007
Filaggrin is a barrier protein in the skin. Two common variants of the filaggrin gene were reported by Palmer et al (Common loss-of-function variants of the epidermal barrier protein filaggrin are a major predisposing factor for atopic dermatitis. Nature Genetics 2006 Apr;38(4):441-6) to be strongly associated with eczema & these findings have been replicated by others, including us. SPINK5 (serine protease inhibitor Kazal-Type5) gene was discovered in association with Netherton Syndrome, a rare disorder that is ubiquitously associated with severe allergy.
Our collaborators have examined the associations of mutations in SPINK5 and FLG with eczema in a German population. The expected strong association between FLG and eczema was found. There appeared to be no strong evidence of a gene-only association of three mutations of SPINK5 and eczema in this cohort but there was evidence of a possible interaction between SPINK5 and FLG in association with eczema (see Appendix). We now wish to extend these observations by applying the same analyses to the data we have collected as part of our ongoing collaboration on FLG and allergis diseases.
The data are already available in a suitable form for analysis (Kate Northstone). THis proposal is to export these data (questionnaire and clinical assessments of eczema from birth to 13 years) to Dr Irvine & Mclean's German colaborators to carry out identical analytical methods to the attached. This will be more effieicient than analysing the data in-house. THe collaborators are willing to sign a confidentialiuty agreement and they will have access to a limited dataset (only that which is requred for this project under usual ALSPAC rules).
The genotyping costs of this project (FLG & SPINK5) have already been borne by the applicants. There are no additional resoucre issues for this project, which is part of an ongoing programme of analyses in collaboration with ALSPAC core personnel (JH, GDS, KN).
B578 - The role of genotype and maternal smoking during pregnancy on offspring smoking initiation - 09/11/2007
We will seek to definitively clarify the relationship between maternal cigarette smoking during pregnancy and subsequent offspring smoking behaviour, and specifically identify any critical risk periods during pregnancy when nicotine exposure is associated with increased risk of offspring smoking.
We will use biochemical validation of smoking and both maternal and offspring genotype to accurately characterise foetal nicotine exposure and validate offspring smoking status, and to determine whether the association of nicotine exposure with subsequent smoking behaviour is explained by, or moderated by transmitted genotype.
We will assess offspring's response to first cigarette to investigate whether any association between foetal nicotine exposure and subsequent smoking behaviour is mediated by sensitivity to nicotine.
Specific research questions:
1. Is there an association between foetal nicotine exposure and subsequent offspring smoking behaviour, in particular initiation?
2. Is variation in nAChR and CYP2A6 genotype associated with subsequent offspring smoking behaviour?
3. Is any observed association between foetal nicotine exposure and offspring smoking explained by transmission of nAChR and CYP2A6 genotypes?
4. Does variation in nAChR and CYP2A6 genotype moderate the association of foetal nicotine exposure and offspring smoking behaviour?
5. Is any association betwee foetal nicotine exposure and/or genotype and subsequent offspring smoking behaviour mediated by subjective response to first cigarette?
Existing Data:
Maternal self-reported smoking status (pregnancy-15 years)
Paternal self-reported smoking status (pregnancy-15 years)
Offspring self-reported smoking status (11-15 years)
Offspring self-report subjective experience of first cigarette (15 years)
Maternal DNA
Offspring DNA
New Data:
Maternal self-reported smoking status (17 years)
Paternal self-reported smoking status (17 years)
Offspring self-reported smoking status (17 years)
Maternal urinary cotinine assay (pregnancy)
Offspring urinary cotinine assay (11-17 years)
B584 - Investigating the role of a novel fasting glucose varient in fetal growth - 06/11/2007
No outline received
B580 - Tonsillectomy for recurrent paediatric tonsillitis - does it work The ALSPAC experience - 06/11/2007
Background:
Debate continues as to the benefit of tonsillectomy. A recent Cochrane review found that there were insufficient trials to fully evaluate the effectiveness of tonsillectomy (1). However, the author of the only studies included in this review stand by their conclusion that tonsillectomy was efficacious in reducing sore throat episodes (1). Furthermore, recent comment from a leading ENT academic asks the pertinent question of the whether the perceived supremacy of this type of review for answering questions related to the use of surgical interventions is justified (2).
Primary question:
Is there a manifest, bias balanced benefit from tonsillectomy versus non-operative management for children with recurrent tonsillitis?
Rationale for using ALSPAC data:
Although there are many studies into the benefit of tonsillectomy, we believe that the ALSPAC database will contain information to add significantly to this debate. Last year there were nearly 30,000 tonsillectomies carried out across England in the 0-14 age group (3). Assuming the national average rate of tonsillectomy applies to the ALSPAC population we expect around 300 tonsillectomies to have been performed on this cohort of children. This study size is comparable with other studies (1).
The incidence of self-reported sore throat is included in the questionnaires, this is the primary outcome that has been previously used to assess benefit of the intervention. However, other outcome measures such as SAT scores and school attendance may be used to demonstrate an association with tonsillectomy. Also, confounders such as socio-economic and smoking status may be examined to balance any potential bias.
Plan of action:
1. We intend to review the ALSPAC database to ascertain the incidence of the exposure variable (tonsillectomy) and the outcome measure (primary being reported sore throat episodes, secondary measures being school attendance/performance).
2. Assess likely bias from confounders between groups.
3. Extract data.
4. Statistical analysis (3. and 4. to be supported by the ALSPAC statistics team, funded by the applicants).
5. Presented locally, regionally and nationally.
6. Publish in the ENT-UK journal (Clinical Otolaryngology).
B575 - Peri pubertal hip geometry in the ALSPAC Cohort - 25/10/2007
Several studies in ALSPAC have revealed significant effects of different factors on bone size as assessed by DXA measurements. Interestingly, effects such as social position persist after adjustment for height, suggesting an influence on bone width (1). This observation is important, since influences on bone width imply that bone shape and geometry are being affected, which may have important implications for the risk of sustaining osteoporotic fractures in later life. Therefore, we are keen to explore potential influences on bone geometry in ALSPAC in more detail.
Initial time constraints in the focus clinics limited the acquisition of all three bone scans (Total body and Hip DXA, and PQCT) mainly due to the unfamilarity of the PQCT scanner, therefore we were limited to using only total body DXA and PQCT. However now the operators have become more familiar with the PQCT scanner the length of time required complete this section has been reduced. Therefore at the end of, and breaks in each clinic session there is now time to perform a unilateral hip DXA scan.
Currently total body DXA scans are being performed, and although total body DXA provides important information about bone density in the body it does not provide any information about the shape and strength of the bone. Other groups are currently measuring physical activity within the cohort and it is postulated that bone adapts to the functional requirements placed upon it. The hip is a key area linking the peripheral and axial skeleton together, and due to the geometric orientation of the hip functional stress and strains are very large, and therefore have the potential to show the greatest adaptation to these stresses and strain.
We are currently investigating the effects of physical activity on bone shape and geometry using pQCT as part of a welcome grant. However pQCT is confined to the use of the peripheral skeleton and we can only measure the tibia. Whilst the information gained from this part of the investigation is important due to the direct measurement of shape and geometry, it can not be used to infer information about the hip. Although hip DXA does not directly measure geometry unlike the pQCT, these parameters can be estimated, therefore we are keen to incorporate this scan into the current clinic, especially as there are no extra associated costs incu
We would like to include a unilateral hip DXA, time permitting, in the densitometry element of the data collection clinic. We are proposing to perform all 3 scans in the Age 17 clinic, and have previously collected information on hip geometry at age 13/14. By collecting hip geometry information at age 15/16 we will be better able to investigate the growth and development of bone whilst the young people are going through puberty, and how this may influence osteoporotic fractures later in life.
Hip DXA uniquely estimates the strength and cross sectional area of the hip, this aspect of bone geometry cannot be obtained via the PQCT or the total body DXA. The hip is commonly associated with osteoporotic fractures later in life and th
B577 - Public Health Consequences of Modifiable Maternal Exposures Offspring Obesity and Cognitive Health in the UK and Brazil - 24/10/2007
Research Programme.The aim of his project is to:
1)Increase the strength of causal inference regarding associations between modifiable maternal exposures (medication and supplement use, diet, smoking, alcohol consumption, physical activity) and offspring obesity, psychological health and cognitive function.
2) Formally compare these associations in a cohort from LMIC (Brazil) and one from HIC (Britain).
I (under the supervision of Professors Davey Smith, Victora, Lawlor, and Drs Lewis and Matijasevich) will implement this utilising:
1) Maternal and child data collected prospectively in the ALSPAC cohort in Britain and Pelotas cohort in Brazil.
2) Using two methods that can provide more robust causal inference regarding effects of maternal intrauterine effects that can be obtained from conventional observational epidemiology approaches11.
a. Comparison of maternal behaviour-offspring outcome associations to paternal behaviour-offspring outcomes. The idea behind this approach is that specific maternal intrauterine effects should result in stronger associations between maternal behaviour-offspring outcome and paternal behaviour-offspring outcome. I have used this approach once in my PhD work12 and would like to develop this relatively novel approach, including more sophisticated statistical modelling (e.g. to account for possible non-paternity further).
b. Use of genetic variants that are related to maternal modifiable exposures as instrumental variables to determine the causal effect of the maternal modifiable exposure. Mendelian randomisation has been proposed as one way of overcoming confounding by utilising the random allocation of alleles from parent to offspring13. Certain genetic variants can be found to affect behaviours e.g. LCT genotype and lactose-containing foods14. Genetic variants such as these can be used as instrumental variables for maternal behaviours, and provide a means for testing an unconfounded and unbiased association with components of offspring health.
ALSPAC. ALSPAC data that would be required for this proposed outline include maternal and paternal questionnaire data on health and behaviours during pregnancy (medication and supplement use, diet, smoking, alcohol) and clinic data in the children relating to size and obesity (BMI, body fat, lean mass, trunk fat etc) as well as psychological measures (depression, anxiety, cognitive function). In addition, genetic data from the DNA samples that are currently being collected in both mothers and children would be required.Pelotas cohort, Brazil.One of the largest and longest running birth cohorts in the developing world, this cohort consists of 5914 infants born in 1982 in the Brazilian city of Pelotas. Follow-up assessments (in varying numbers of children) have been carried out at varying stages of development ranging from at birth, infancy and childhood (age ranges from less than 1 year to 5 years), adolescence (12 to 19 years) and young adulthood (22 to 24 years). A wide range of information is available, including family socioeconomic position, maternal characteristics, maternal health and behaviours in pregnancy, infant perinatal data, environmental factors, infant nutrition, as well as physical and psychological measures in infancy, childhood and adolescence. Similar data is also available in another Pelotas cohort initiated in 1993.DNA samples will be collected in a planned follow up study in 2008.Existing collaborations between ALSPAC and Pelotas.There is enormous potential (given the similarity of design and measurements in the two studies) for scientifically valuable collaborations between these two cohorts, and the two scientific directors (Davey Smith and Victora) are eager to facilitate and support such collaboration. With an award by the Wellcome Trust for Dr Alicia Matijasevich, who works with Professor Victora on the Pelotas cohort to spend six months in Bristol on a project comparing socioeconomic differentials of maternal and childhood outcomes between the two cohorts. I intend to build upon this work in the current proposal and further strengthen collaborations between the two cohorts.
B576 - Dietary patterns in early childhood and IQ - 23/10/2007
There have been several studies showing the effects of vitamin supplementation, nutrient deficiency and recent dietary intake on IQ in children [see 1 for a review]. We have recently shown in the ALSPAC cohort that overall dietary patterns in early childhood are associated with both later child behaviour and school performance [2,3]. There appears to be little known about the long-term effects of early diet (with the exception of infant feeding) on later child cognition, as assessed by IQ. The use of dietary patterns aims to overcome the inherent problems of examining individual food and nutrients associations, namely, the inter-correlations between these foods and nutrients. The proposed analysis provides a novel approach to examining the effects of dietary intake on cognitive development.
A preliminary analyses assessing the effects of childhood dietary patterns on IQ has already performed in order to feed into a grant proposal to be submitted to NIH in Feb 08 by Tomas Paus (Nottingham), a primary aim of which is to evaluate the role of nutrition during the first five years of life on brain structure in adolescence.
At his request, I examined the associations between dietary patterns in early childhood (at ages 3, 4, 7 and 8 years [4,5]) and overall IQ assessed at 8 years of age. Initial results suggest that there may be an effect of overall dietary patterns in childhood and IQ. In particular a 1 SD increase in the 'processed' component score at each age (3, 4, 7 and 8) was associated with a decrease of between 2 and 4 points on the WISC IQ scale, while a 1 SD increase in 'health conscious' component score at each age resulted in a 2 point increase. After adjustment for a limited number of confouding or mediating factors the effect sizes were attenuated, though strong relationships remained the 3-year data; as such further analyses is required to take into account additional factors which may be important after a thorough review of the literature. This will determine whether the observed effects are real or due to residual confounding.
Proposed further anlaysis will include:
1. Examining the verbal and performance components of the WISC;
2. Examining the results of the subtests of the WISC;
3. Further adjustment for other factors, including maternal diet, aspects of which have been shown to be associated with IQ in this sample [6];
4. Using cut-offs for IQ in order to determine the risk of poor performance.
Although this work is unfunded it will be of particular use to the NIH grant and is a natural follow-on to the work constituting my PhD. It will also feed into other funding opportunities to investigate the effects of diet on other cognitive and neuro-developmental outcomes.