Proposal summaries
B424 - Analyses of relation of parity to atopy in ALSPAC - 02/11/2006
Background: Childhood allergy and sibship
There is consistent and strong evidence that the prevalence of atopy and hayfever are lower in children from large families or of higher birth orders1. The pattern is less consistent for childhood asthma, probably because its phentoype is less specific and easily confused with infection-related and other forms of non-atopic wheeze.
Sibship size and birth order are inevitably correlated - especially where average families are small - and it is not always easy to examine their independent effects. The apparent protection offered by increasing family size was originally ascribed to variations in the rates of early childhood infection and thus formed the basis for the 'hygiene hypothesis'2. This remains the most plausible and parsimonious explanation for much of the epidemiology of childhood allergy; but it does not preclude additional mechanisms related to birth order. For example, two studies of UK populations, separated in age by about 30 years, were unable to account for birth order effects by examination of recorded infections in early childhood3;4.
Within representative cohorts of families living in Ashford (Kent), Barcelona and Menorca we originally observed, on cross-sectional analysis, that mothers - but not fathers - who have given birth to more children are less often atopic. This relationship was not explained by maternal age5. Subsequently and prospectively, within the Ashford population, we reported that over seven years the loss of maternal atopy and hayfever are associated with a higher number of intervening pregnancies6.
One explanation for these observations is that they reflect changes in maternal and consequently maternal-foetal immunology with successive pregnancies, and that this in turn influences risk of allergic disease in the offspring. If this were the case one might expect to see a relation between parity and cord IgE. The observation that the birth order effect may be stronger if older siblings are male7, could reflect stronger immune responses of the mother to male compared to female foetuses. If maternal-foetal immunology is important, then one might expect a mother's change of partner to influence the birth order effect and for a child with older sibs born to a new father to have the same risk of atopy as a first-born child. This is analogous to the risk of pre-eclampsia which is higher in first than in subsequent pregnancies, but reverts to the risk for primiparous women in later pregnancies if the mother changes partner.
B422 - Social currency and health seeking behaviour - 31/10/2006
No outline received
B420 - Norweigian biobank for human primary teeth - 30/10/2006
30/10/2006
B419 - Conduct disorder at 17 - 30/10/2006
No outline received
B418 - Development of ear drum retractions - 30/10/2006
No outline received
B417 - Disordered eating in adolesence A longitudinal study of risk factors - 30/10/2006
Disordered eating is a common problem in pre-adolescents and adolescents. About 30% to 60% of young girls show disordered eating at some point between the ages of 12 and 18
Abnormal eating patterns such as under-eating and binge eating are associated with a high disease burden (15th among the top 20 causes of disability)
Disordered eating encompasses extreme forms of eating such as the eating disorders (ED), anorexia nervosa (AN), bulimia nervosa (BN), eating-disorders not otherwise specified (EDNOS) including binge eating disorder (BED); and less extreme problematic eating, such as over-eating and under-eating as well as unhealthy weight-control behaviours: self-induced vomiting, laxatives, diet pills, excessive exercise or fasting for weight loss. It affects the physical and mental health of young people, impacts upon school performance and interpersonal relations, and also increases the risk for eating disorders in later life.Eating disorders have the highest mortality rate amongst psychiatric disorders, and the mortality rate associated with anorexia nervosa is 12 times higher than the death rate of all causes of death for females 15 - 24 years old. Moreover, disordered eating might induce long-standing changes in the neurobiological pathways affecting eating behaviours.
The purpose of this study is to identify the risk factors related to the development of disordered eating and to determine risk factors for the persistence of disordered eating during adolescence. This will aid the development of early intervention and preventative strategies for disturbed eating and in so doing have an impact on public health
B416 - TIM data request - 30/10/2006
No profile received
B414 - European Cohort Network EUCCONET - 16/10/2006
No outline received
B413 - Thyroid function in maternal sera and development and cognitive function - 16/10/2006
B412 - The lifecourse determinants of moles in a contemporary population of children - 16/10/2006
No profile received
B407 - Maternal and paternal alcohol use in pregnancy - 02/10/2006
Evidence increasingly suggests that mental health problems are associated with insults during critical times of brain development, and also by exposures over an individual's life course. These include in-utero exposures, which may lead to subtle neurobehavioral difficulties, and contextual exposures such as neighbourhood quality and quality of child-rearing environment. Much of the work in this area to date has focused on early life determinants of schizophrenia, and to a lesser extent depression and suicide. Further, there is a body of evidence relating birthweight to cognitive function in childhood, though a recent sibling-based analysis suggested that this association was driven by fixed familial factors such as background socioeconomic position and behaviours/exposures that are similar for all siblings within a family. (1)
However, there is relatively little work on the role of early alcohol exposure on the occurrence of a range of cognitive, behavioural and emotional difficulties. Exposure to alcohol consumption in pregnancy is an example of the effects of an exposure during a sensitive period. The teratogenic effects of alcohol causes a variety of adverse developmental outcomes including Foetal Alcohol Syndrome (FAS) and Foetal Alcohol Effects. (2) Whereas consistent excessive drinking in pregnancy is definitely associated with more severe symptoms, the evidence is unclear as to the impact of more moderate drinking exposure on milder forms of developmental outcomes. However concerns remains over the fact that even moderate consumption of alcohol in pregnancy may increase the risk of mild cognitive impairment, ADHD and learning and behavioural difficulties. (2) Finally there is emerging evidence pointing to an association between alcohol and tobacco use in pregnancy and the development of addictive behaviours, such as addiction to alcohol. (3-6)
The mechanisms underlying these associations are unknown. It is assumed that the effects are due to specific intrauterine exposure, but genetic factors and shared familial factors (including socioeconomic position, shared/learnt familiar behaviours) may well explain any link between moderate alcohol consumption in pregnancy and later effects on offspring cognitive function and behaviour. One way to further explore this would be to compare associations of maternal alcohol consumption during pregnancy with offspring outcomes to the same associations with paternal alcohol consumption. To date no previous study has done this.
There are only a handful of studies with the capacity to test the early development of alcohol problems in children. Further evidence is needed to assess whether in-utero exposure to moderate alcohol consumption truly contributes to later developmental problems. If this is so it is also important to understand the mechanisms underlying these associations.
The aim of this proposal is to use ALSPAC data in order to determine whether intra-uterine exposure to alcohol consumption (assessed by maternal self-report of alcohol consumption during pregnancy) is related to poorer cognitive function, academic difficulties, behavioural problems (eg Attention Deficit Hyperactivity Disorders) during the childhood years and addictive behaviours later in adolescence. The association of maternal alcohol consumption during pregnancy with these offspring outcomes will be compared to similar associations with paternal alcohol consumption (based on self-report by the partner of the mother with restriction to those who define themselves as the biological father). This comparison will facilitate our ability to determine whether there is a true intrauterine effect, since if there is one would anticipate associations only with maternal alcohol consumption. Similar association with paternal intake would suggest that genetic factors and/or shared family environmental factors explain the association rather than specific intrauterine effects.
B406 - Equity of access to health care for visual problems in childhood An analysis of ALSAC data from children 7 years of age - 02/10/2006
Experimental studieshave suggested in animals1,2 and children3 that treatment at an early stage for childhood visual problems leads to improved visual outcomes . There is debate about the consequences for a child of treating vs. not treating their visual problem, but data from ALSPAC suggests some common visual problems are associated with under achievement at school8 . There is also disagreement about the use of population vs. targeted visual screening services, offered at different stages of childhood and their effectiveness in reducing visual problems in children at population levels4
Although, in theory, eye services should be accessible to everyone, it is not known "if the people who use it are the people who need it". Inequity access to health care is defined as a mismatch between provision of clinical services and clinical need. 5 A study6 by the ALSPAC group has highlighted a clear gradient in maternal social class and prevalence of childhood hypermetropia as well as amblyopia at age 7. We therefore have robust epidemiological evidence that inequalities in visual health do indeed exist. The aim of this proposal is to now relate this pattern of need to actual receipt of clinical eye services and identify whether the latter pattern is consistent with need, thereby identifying if equitable access to care does not does not exist within this population and possibly the UK in general. Such an approach has been used for other chronic diseases.7 In addition we will adjust for the potential confounding effects of other covariates such as maternal eye problems, other siblings in the family
B405 - Acknowledging Model Uncertainty in Social Science - 28/09/2006
No outline received
B404 - A study of the associations between blood pressure and anxiety in pregnant mothers - 25/09/2006
No outline received
B401 - Longitudinal modelling of energy imbalance based on changes in body composition in ALSPAC participants 9-13 years - 15/09/2006
Obesity is a chronic disorder of energy balance: the amount of energy being spent must remain less than the amount of energy consumed for a long period of time for obesity to develop. The traditional paradigm for the development of obesity is that a process of 'creeping weight gain' occurs1, and that the rate or degree of positive energy balance is very small - in both adults and children - when considered over long periods (equivalent to perhaps as little as 50 kcal/day)1,2. This paradigm translates directly to public health messages aimed at persuading individuals to make small lifestyle changes in order to prevent obesity ("eat a little less, do a little more")1. The paradigm has been challenged by the finding that, in at least one population at high risk of obesity (Latino children, adolescents, and young adults in Houston Texas3), rates of positive energy balance are typically very much higher. In that study, the median positive energy balance was equivalent to greater than 200kcal/day for a year3.
B403 - Being 16 Camera Project - 15/09/2006
No outline received
B400 - Gene and environmental influences on childhood asthma STELAR Study Team for Early Life Asthma Research Collaboration - 14/09/2006
No outline received
B396 - DANVA Analysis - 11/09/2006
(No outline received).
B395 - Relationship between Thyroid Status and Skeletal Development - 11/09/2006
(No outline received).
B394 - MTHFR C677T Genotype and Obesity - 11/09/2006
TheMTHFRTT genotype is associated with an increased frequency of obesity relative to the CC genotype, due to a reduction in availability of folate for methylation observed with this genotype.
We plan to examine the association between the MTHFR genotype in 4 distinct populations within 3 Cohort studies; The British Women's Heart and Health Study, Avon longitudinal study of Parents and Children (2 populations: mothers and children) and Copenhagen City Heart Study.