Proposal summaries
B259 - Reducing emotional distress in adolescence the role of the school in influencing vulnerability and resilience - 01/09/2005
The proposed study is part of a wider application to the MRC for a postdoctoral Special Research Training Fellowship in Health Services and Health of the Public Research. The overall theme of the application is the causes of emotional distress in early to mid adolescence and the support needs of those who experience this, with a particular focus on the school context, in terms of risk factors and potential avenues of support. The aim of this particular study is to assess incidence and school-related risk factors for deliberate self-harm in 14-15 year olds in ALSPAC. The young people in the sample have already been asked during their clinic interviews at age 11 about episodes of self-harm and suicidal thoughts (frequency, timing and nature of episodes). The children were asked the following questions: (a) "Have you thought of killing yourself?" (b) "Have you ever hurt yourself on purpose?" (c) "Have you ever made plans to kill yourself?" (d) "Have you actually tried to kill yourself?". I propose to build on this data, by including several questions in the questionnaires to be sent out to the ALSPAC teenagers at age 14-15 years.
B257 - Socioeconomic patterning of cognitive function in children - 01/09/2005
Background. Cognitive function and intelligence quotient (IQ) have been related with adult mortality in some but not all studies. IQ was not related to coronary heart disease or stroke after the age of 651 and childhood IQ was not related to mortality in women2. Adjustment for socioeconomic circumstances partly explains this association3. Furthermore, childhood cognitive ability could determine school performance and thus, influence later socioeconomic position. Research in this area is limited and ASLPAC offers a unique opportunity to investigate whether cognitive function is already socially patterned at a young age.
Objective. The objective of this project is to investigate whether cognitive function in childhood is socially distributed, using different aspects of cognitive function and different measures of socioeconomic position.
Main variables for this project. We will need variables measuring cognitive function (e.g. McArthur Communicative Development Inventory at 20 months, Pre-School Language Scales (PLS-3), McCarthy Scales of Children's Abilities at 36 months, etc.), family background details, and the primary carer's verbal functioning (Mill Hill Vocabulary Scale), are and individual socioeconomic position indicators, socio demographic characteristics and school characteristics.
Statistical analysis. We will assess the social patterning of cognitive function in the children, with particular attention to using different indicators of life course socioeconomic position to describe this distribution. We will conduct multiple regression analysis. Sensitivity analyses will be carried out to explore the degree to which misclassification of both exposures and confounders could influence the observed effect estimates.
References.
1. Hart CL, Taylor MD, Smith GD, et al. Childhood IQ and cardiovascular disease in adulthood: prospective observational study linking the Scottish Mental Survey 1932 and the Midspan studies. Soc Sci Med 2004;59:2131-8.
2. Kuh D, Richards M, Hardy R, Butterworth S, Wadsworth ME. Childhood cognitive ability and deaths up until middle age: a post-war birth cohort study. Int J Epidemiol 2004;33:408-13.
3. Huisman M, Kunst AE, Mackenbach JP. Intelligence and socioeconomic inequalities in health. Lancet 2005;366:807-8.
B256 - The origins and outcomes of persisting phonological impairment - 01/09/2005
* To establish prevalence figures for SI at ages 5 and 8 years.
* To identify factors that are predictive of SI at ages 5 and 8 years.
* To describe the profiles of children with SI at 5 and 8 years in terms of language skills,
behaviour, self esteem and the impact on the child's education and social relations
* To investigate the existence and nature of subgroups of speech problems.
B410 - Early determinants of dietary salt intake The association of sodium intake in infancy with blood pressure in later life Maternal iron status during pregnancy and offspring blood pressure - 01/08/2005
This is a proposal for analysis of the ALSPAC data - and has 5 different research questions:
1.Does dietary sodium intake track from infancy through to age 7? In particular is
dietary sodium intake in the first year of life strongly associated with intake at age
7?
2.Is dietary sodium intake at age 7 greater among children who have experienced
diarrhoea, vomiting and/or dehydration in the first year of life than those who have
not experienced these illnesses? Is there an association between the number of
episodes of diarrhoea/vomiting/dehydration and dietary sodium intake at age 7?
3.Is infant feeding (ever breast fed and duration of breast feeding) related to dietary
sodium intake at age 7?
4.Is birth weight related to dietary sodium intake at age 7?
5.Is childhood socioeconomic position related to dietary sodium intake at age 7?
B254 - Assessment of future ovarian reserve in childhood - 01/08/2005
(No outline received).
B253 - Profiling children who stutter - 01/07/2005
Stuttering is a disabling condition that can have adverse effects on a child's life in school, and on young adults' occupational choice. Many children experience disruptions to their fluency in their preschool years. However, research has not been able to predict which children are likely to go on to be fluent and which children will go on to stuttering.
Using a study with large numbers, a wealth of data about children's development and unique speech data provides an opportunity to investigate this question. The Avon Longitudinal Study of Parents and Children recruited 14000 mothers during their pregnancy. The children were born in 1991/2 and the study has followed them as they have grown up, with questionnaires and assessments. Samples of the children's speech will be analysed to establish which children show stuttered speech. The study will then investigate developmental histories, educational successes and social behaviours to compare children who outgrow their stuttering with those who do not. Identifying which factor predict recovery can inform how therapists select which children need early intervention and also shape the development of therapy approaches and techniques that are needed to help prevent stuttering and its adverse effects.
B248 - The role of parental illness beliefs and behaviour in the epidemiology of fatigue in adolescence - 01/06/2005
(No outline received).
B246 - Genetics of obesity - 01/06/2005
The present proposal seeks support for a consortium arrangement between the University of Western Australia (Australia) and the University of Bristol (UK) toconduct genetic epidemiological analyses of a unique prospective longitudinal birth cohort in order to evaluate the etiological pathways underlying the childhood precursors of T2D - obesity and metabolic factors such as IR and GI. Whilst the principal consortium members include Australian and British researchers, collaborative arrangements have also been arranged at an "as required" basis with researchers from McGill University, University of Leicester, University of Oxford, University of Cambridge and the NIDDK.
As a result of these arrangements, there is a substantial foreign component present in this proposal. As described in the Research Plan, the ALSPAC group at Bristol University will contribute their epidemiological expertise and the rich ALSPAC cohort resource, the group at the University of Western Australia will contribute their expertise in genetic epidemiology and informatics, and the groups at McGill University/Genome Quebec Innovation Center and Oxford will contribute their expertise and knowledge of high-throughput genotyping.
Over the preceding 12 months, UWA (Palmer) has coordinated the formation of the new consortium between Bristol and Perth. This role arose out collaborations and interactions between these two groups, and because of the self-evident synergies and mutually complementary skills and knowledge. Dr Palmer spent a 4 month sabbatical as a Leverhulme Trust visiting Professor with the ASLPAC group in 2005, and Dr Ness will be visiting Perth later in 2006.
The prime rationale for the involvement of the senior collaborators at Oxford (McCarthy), Cambridge (Wareham) and the NIDDK (Knowler) is their capacity to provide DNA samples from well-phenotyped studies for replication of positive signals from this study. As set out in the Research Plan, our ability to confirm positive signals by replication in multiple independent datasets is an essential part of strategy (although funding for the replication comes from each group and non-NIH sources, and no funds for this part of the project are requested in this application). In addition to supplying replication samples, these senior collaborators also provide intimate knowledge of their samples and the phenotypic characteristics relevant to T2D in their respective populations, along with specific clinical, epidemiological and genetic expertise related to T2D.
The analytic team from Bristol (Green), Oxford (Cardon), Leicester (Burton) and Perth (Palmer) represent an experienced team of senior statistical geneticists and mathematicians who collectively have a substantial amount of experience in the applied analysis of complex datasets and in methods development in biostatistics. These senior investigators and collaborators have complementary experience and interests, and a long history of collaboration and interaction on a number of projects. Current collaborations include an ongoing activity and obesity study undertaken by Dr Ness and Dr Wareham, whilst Professor Smith, Professor Burton, Dr Ness and Professor Palmer are involved in the ALSPAC programme. Based on the relevant expertise of these investigators and the high standard of current and past collaborative efforts, we believe that this is an ideal team to guide the analysis of large amounts of SNP data in the complex ALSPAC datasets.
To maximize efficiency, the project will utilize a centralized high-throughput genotyping approach. For this purpose, the Genome Quebec Innovation Centre (Montreal, Canada) has been closely involved with the development of this proposal. In addition, Dr Hudson has a long-term interest in the genetics of T2D and obesity and close collaborative links to a number of senior investigators and collaborators involved in this proposal. This made the Innovation Centre the logical partners in the development of this proposal. As their contribution to the HapMap demonstrates, the Innovation Center remains at the forefront of efforts to develop high-throughput genotyping and related analysis tools, and the commitment of their expertise and technological capacity to this project is a valuable component of our plans. All equipment and maintenance costs are covered by internal Innovation Center funds. The consequence is a cost price that is below that available from any comparable commercial or academic source. In addition to their commitment to genotyping of the ALSPAC resource, the Innovation Center will also support the genotyping and resequencing needs of our replication and follow-up studies (for which funding is not sought in this application). Finally, existing strong 3-way links between Tom Hudson's group at the Genome Quebec Innovation Center, George Davies-Smith's group at Bristol University, and Lyle Palmer's group at the University of Western Australia will facilitate information exchange between the 3 groups, enabling us to maximize the efficiency of the project. Prof Hudson will be a Visiting Professor with Prof Palmer's group in Perth in August 2006.
B244 - Does maternal exposure to polycylic aromatic hydrocarbons cause intrauterine restriction An investigation of interactions between maternal smoking in pregnancy - 01/05/2005
(No outline received).
B243 - Correlates and antecedents of receptive non-verbal skill - 01/05/2005
(No outline received).
B240 - What makes a normal optic nerve Assessment and clarification of a unique library of digital images from a population based cohort of children aged 12 - 01/05/2005
(No outline received).
B239 - Cigarette smoking - and neurodevelopment - 01/05/2005
(No outline received).
B238 - Neurodevelopmental consequences of cannabis on child adolescent development - 01/04/2005
(No outline received).
B237 - Parenting in ordinary families diversity complexity and change - 01/04/2005
The aim of this proposal is to add to the literature by describing parenting during early and middle childhood in different social and cultural groups: those exposed to financial stress, poor social support and specific challenges such as illness or physical disability. We plan to examine continuity and discontinuity in these contexts and describe the effects of intergenerational continuity on parenting practices.
B235 - Adolescent onset conduct problems a biopsychosocial model of risk - 01/04/2005
Rates of conduct problems rise sharply in the teens. Though less noxious than childhood onset
disruptiveness, adolescent conduct problems - affecting a much wider segment of the population -
nonetheless compromise later life-chances, impair relationships, and impact on both physical and mental
health. Most worrying, our research suggests that levels of adolescent conduct problems have been rising
in the UK across the last quarter of the 20th century, but that their implications for later adjustment remained
unchanged.
Much is now known about risks for early childhood conduct problems. By contrast, risks for adolescent
onset difficulties are less well understood. This proposal is designed to fill that gap, capitalizing on two key
UK data sources:
First, it will build on the rich developmental data already collected in the Avon Longitudinal Study of Parents
and Children (ALSPAC). Beginning in pregnancy, ALSPAC has amassed extensive developmental,
behavioural, psychological, biological and social data on a cohort of some 14,000 children. Born in 1991
and 92, the ALSPAC cohort are now entering the key risk period for adolescent onset conduct problems.
We propose new data collection at ages 15-16 which, in conjunction with existing measures, we will use (i)
to characterize trajectories of conduct problems across childhood and adolescence; (ii) to clarify risks for
adolescent onset conduct problems; and (iii) to differentiate risk profiles of early onset disruptive behaviours
that do and do not persist.
Second, we will use publically available data from the first four waves of the Edinburgh Study of Youth
Transitions and Crime (ESYTC) to complement and replicate findings on adolescent sources of risk.
Beginning in early adolescence, ESYTC has tracked a cohort of some 4300 young people annually from age
12, assessing individual, family and social influences on adolescent antisocial behaviour using measures
closely compatible with those available and planned for use in ALSPAC.
Taken together, these two complementary data sources offer valuable opportunities to advance
understanding of adolescent conduct problems and the factors most central to risk.
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Summary of Health and Wealth Implications:
Child and adolescent conduct problems impose heavy burdens on individuals, their families and the wider
society. Follow-up studies consistently point to increased risks of educational and occupational
underachievement; failed relationships, family breakdown and poor parenting; and high rates of problems in
both physical and mental health. At the societal level, health economic studies highlight the financial costs
involved. Childhood conduct disorder is associated with a ten-fold increase in costs; less severe difficulties
still elevate costs by more than a factor of 3. Most worrying, our research suggests that levels of adolescent
conduct problems rose steadily in the UK across the last quarter of the 20th century, but that their impact on
later adjustment remained unchanged. Effective techniques are now available for intervention in early onset
conduct problems; much less success has been achieved with treatments beginning in the teens. Clearer
identification of risks for adolescent conduct problems promises important benefits.
B234 - Childrens pathways from risk to resilience - 01/04/2005
(No outline received).
B232 - Depression in mothers and fathers in the postnatal period investigating the risks to childrens cognitive emotional and behavioural development - 01/04/2005
(No outline received).
B230 - Genetic and environmental determinants of arterial function in childhood insight into causal pathways - 01/03/2005
Arterial disease that underlies stroke and heart attacks begins in childhood. Changes in the arterial structure and function are seen as early as age 10. We plan to examine which genetic and environmental factors are important at the onset of disease in a well characterised cohort of 7,507 9-11 year old children from the ALSPAC study, in whom we have made detailed measurements of arterial structure and function. This will help to understand the respective contributions of well-known risk factors, such as cholestrol and blood pressure, as well as novel influences such as inflammation and obesity. Better risk prediction and new opportunities for treatment should result.
B228 - Identification of pregnancies at high risk of pre-term delivery using data available in the 1st and 2nd trimesters - 01/03/2005
(No outline received).
B227 - Sibling competition for family resources child development and the determinants of fertility an evolutionary analysis of British families - 01/03/2005
1. Abstract
Evolutionary theories of parental investment suggest that parents face a trade-off between offspring quantity and quality, so that an increased number of children at the same wealth dictates negative consequences for individual children. Taking this prediction as a starting point, this study aims to 1) examine the consequences of high fertility on social and health aspects of child development, 2) examine the mechanisms, in terms of differential parenting behaviour, which lead to these consequences, and 3) investigate socioecological factors (namely kin support and wealth) which may relate to variation in the magnitude of effects across the British population. Finally, 4) the study will relate the findings of 3) to theories of fertility determination. When the effect of number of siblings is more negative, actual fertility is expected to relatively lower, and vice versa. All data will be sourced from the Avon Longitudinal Study of Parents and Children (ALSPAC), an ongoing extensive longitudinal database of children, and their parents, born in the Avon area of the UK.
2. Theoretical Background
Human evolutionary ecology is the study of the ecological and evolutionary basis of human behaviour, and the roles of behaviour in enabling humans to adapt to their diverse environments (Cronk, 1991; Voland, 1998; Winterhalder & Smith, 2000). A principle focus of human evolutionary ecology is patterns of human reproduction, and the life-history trade-offs this presents. Two main categories of life-history trade-off can be identified, and in an evolutionary sense, how one mother fares relative to another depends on how well these are handled over the lifecourse. The first trade-off is between current and future reproduction (Gadgil & Bossert, 1970; Williams, 1966), and is investigated empirically on the potential impacts of high fertility and early age at reproduction on a mother's survival and subsequent fertility (Perls, Alpert, & Fretts, 1997; Sear, Mace, & McGregor, 2003; Westendorp & Kirkwood, 1998). The second, and the focus of the proposed research, is between offspring number and offspring quality (Lack, 1947, , 1954; Lessells, 1991; Smith & Fretwell, 1974; Williams, 1966). Since both trade-offs involve the allocation of parental resources (time, wealth, energy) into alternative investments, and since an individual's resource budget is finite, these trade-offs are seen as inevitable.
The quantity-quality trade-off envisages children as competing for family resources, so that, controlling for parental resources, higher fertility will be related to negative consequences for individual children. Within developed countries evidence for this primarily comes from sociological studies of educational achievement. Across various measures of intellectual skills and educational success, individuals with the fewest siblings do the best according to studies that have used multiple datasets collected in both the United States (Alwin, 1991; Blau & Duncan, 1967; Circirelli, 1978; Downey, 1995; Featherman & Hauser, 1978; Kuo & Hauser, 1997; Mercy & Steelman, 1982; Parcel & Menaghan, 1994; L. C. Steelman, 1985; Zajonc & Markus, 1975), and Europe (Belmont & Marolla, 1973; Demographiques, 1973; Eysenck & Cookson, 1970; Majoribanks, 1974; Nisbet & Entwistle, 1967).
Comparatively little research has been yet carried out on health outcomes, at least within the developed world. There are however, a number of studies demonstrating a negative relationship between sibship size and child health and nutrition in developing countries (Ballard & Neumann, 1995; Hagen, Barret, & Price, in press; Hagen, Hames, Craig, Lauer, & Price, 2001; Nanda, 1996; Rao & Goplan, 1969; Wofle & Behrman, 1982). Given that other aspects of family structure, such as parental divorce, are known to hold important health consequences in developed countries (Mauldon, 1990; Quinlan, 2003) it seems likely that such effects may also occur in countries such as Britain.
Variation in the Quantity-Quality Trade-off
While the inverse relationship between number of siblings and educational outcomes has been heralded as one of the most consistent findings in the status attainment literature (Downey, 1995; L. Steelman, Powell, Werum, & Carter, 2002), there is a clear indication of variation in its magnitude across population subgroups. For example, Shavit and Pierce (1991) reported that, within the US, although sibship size had a negative impact on educational attainment for Ashkenazi Jews and Oriental Jews, it had no effect on Moslem Arabs. Similarly, Downey & Neubauer (1998) found the negative effects of sibship size were slightly weaker amongst Mormons than Protestants. Blake (1989) reports comparable differences between American Catholics and Protestants. Furthermore, the few studies on the consequences of high fertility on child education in less developed countries have proven inconclusive. Some studies have found a strong negative impact of family size on child outcomes (Birdsall, 1982; Knodel, Havanon, & Sittitrai, 1990), others have found it to be less important ((Mock & Leslie, 1986)) or even positive (Chernochovsky, 1985; Gomes, 1984). There are also a number of developing world studies that have failed to find a relationship between family size and child health and nutrition (Hesketh, Qu, & Tomkins, 2003; Tada, Keiwkarnka, Pancharunti, & Charoonsawasdi, 2002). Many authors have made suggestions in attempt to explain this variation, between and within studies, however, there has so far been little formal testing of the socioecological factors that may lie behind it.
One factor that may be important is the presence and relationship of extended kin to the children under study (Downey, 2001). Intuitively if sibship size reflects the dilution of familial resources amongst children, then measures of extended family structure may reflect the amount of resources available for dilution. Even at an equal parental wealth, spreading the costs of child raising with a stable partner or extended kin may lower the burden placed on the mother and so buffer the disadvantages of children from large families. Could it be then that the variation outlined above may be attributable to differences in the role of extended kin? Mormons for example have particularly strong profamily norms, as do Catholics (Blake, 1989). Developed countries are also characterised by a much more pronounced nuclearisation of the family relative to developing countries.
Human behavioural ecologists have a long standing interest in assistance of extended kin given to mothers in rearing children, as it hypothesised that this assistance may be responsible for the evolution of a number of unusual features of human life-history. These features include short interbirth intervals relative to other primates, and menopause (Hawkes, 2003). Thus, the contribution made from kin groups has been analysed across a wide range of historical and contemporary populations (Beise, 2004; Lahdenpera, Lummaa, Helle, Tremblay, & Russell, 2004; Marwole, 2001; Sear, Mace, & McGregor, 2000; Sear, Steele, McGregor, & Mace, 2002; Tymicki, 2004). What is clear from this body of research is that, while there is much variation in the role of particular kin across cultures, extended kin are often central figures in the development of children. Gibson & Mace (2005) for example demonstrate clear positive effects of assistance from grandmothers on child height and survival in rural Ethiopia. Thus these studies provide supporting evidence for the hypothesis that differences in the magnitude of sibship effects, both within and between societies, may be attributable to differences in the role of extended family.
Another factor that may lead to variation in the quantity-quality trade-off across population subgroups is socioeconomic class.Downey and Neubauer(1998) for example, have suggested that additional siblings adversely affects finances set aside for children in high income families, but has virtually no effect in low income families. They propose this is due to a difference in how number of siblings affects the distribution of base resources (i.e. those needed for survival) versus surplus resources (i.e. investments designed to enhance long-term opportunities). Only parents above a certain threshold of wealth are able to distribute surplus resources to children, so that parents below this threshold pay few costs to higher fertility as each child will only receive the minimum (base) resources in any case. A potential example of this effect could be drawn on schooling. All children of low income families will go to comprehensive school regardless of the number of siblings they have, however, in high-income families children may be able to go to private school depending on the number of siblings the family resources are to be diluted amongst. A similar effect could lead to differences in access to public vs. private health care.Downey and Neubauer's(1998) distinction between base and surplus resources is insightful and warrants serious thought and empirical investigation.
Theories of Modern Fertility
Understanding the socioecological factors that lead to variation in the costs associated with high fertility amongst British families also has direct relevance to our understanding of the determinants of modern fertility.
Among hunter-gatherer and other subsistence-based societies there is considerable evidence that fertility patterns reflect a set of physiological and behavioural responses that optimise levels of parental investment in such a way as to maximise Darwinian fitness (for reviews: Bentley, 1999; Kaplan, 1996). Evolved decision rules are hypothesised, allowing parents to strategically track the effects of parental investment on child outcomes and optimise their behaviour accordingly (Kaplan, 1996). However, given the phenomenon of low fertility, sometimes below replacement level, in post demographic transition societies some controversy rests on the role of these decision rules in determining modern fertility rates. In traditional societies wealth and fertility show a positive correlation (e.g. Low, 1990; e.g. Mace, 1996; Voland, 1990). Yet in those societies that have undergone demographic transition; that is, a period of history in which dramatic changes in fertility and mortality have occurred along with a rise in living standards, (Borgerhoff Mulder, 1998) wealth and fertility appear to show a negatively relationship (e.g. Lam, 1986; Perrusse, 1993). Furthermore, during the transition the rich have tended to reduce their fertility first. Why would people choose to limit their reproduction voluntarily when resources are plentiful? Some authors have suggested that the lack of a positive relationship between wealth and family size in modern societies is proof that humans no longer behave in a manner that optimises their reproductive success and that evolutionary approaches do not explain current family sizes (Vining, 1986).
Traditional methods of historical and economic demography, however, have failed to develop a robust theory of demographic transition. In response human behavioural ecologists have suggested a number of hypotheses to solve this dilemma (reviewed in(Borgerhoff Mulder, 1998). At the centre of these hypotheses lie changes in the quantity-quality trade-off, and they identify similar socioecological factors as those discussed above. For example, Turke (1989) and Draper (1989)both hypothesise that the reduced levels of fertility seen in modern societies may be a response to the absence of close kin networks. This is because strong extended family relationships decrease the costs of childrearing by providing free childcare and investment.Draper(1989) further suggests that even if the traditional role of extended kin has been replaced by friends or the government in modern societies, our evolved decision rules may still lead us to act as if extended kin are necessary for high fertility.
Other authors have suggested that suggested that increased wealth itself, and the increased opportunities this brings, may be lead parents to evaluating low fertility as the optimal strategy. As Kaplan et al.(1995) argues; a reduction in fertility would be strategically beneficial for wealthier individuals if the vale of investing resources in a child are a (positive) nonlinear function of the amount invested. This might happen, for example, because knowledge is cumulative: each additional unit of knowledge or skill acquired provides the platform for an even larger subsequent educational gain or access to much greater socioeconomic opportunities (as seems plausibly to be the case in our knowledge-based economies). However, these hypotheses remain somewhat speculative in the face of a lack of empirical studies into the relative costs of high fertility across subgroups in modern populations, and data on how these costs relate to actual family size.
3. Research Questions & Methodology
All data will be sourced from the Avon Longitudinal Study of Parents and Children (ALSPAC), an ongoing extensive longitudinal database of children, and their parents, born in the Avon area of the UK. The following research questions are identified:
A. What are the consequences of high fertility on child development in British families?
To date research into the effects of sibling number on child development has been heavily dominated by cross-sectional studies. Steelman et al.(2002), in a review of the sibling configuration literature to date, identify this as a area of major concern, not least because a recent large scale longitudinal analysis (Guo & VanWey, 1999) failed to replicate the negative impacts on child education that have been demonstrated in so many cross sectional analyses. ALSPAC then, provides the perfect resource to respond to these concerns, and estimate the effect of number of siblings on child outcomes with longitudinal data in Britain.
The nature of ALSPAC will allow for both educational and health aspects of child development to be considered. It is believed that analysing both within the same study will be extremely advantageous, as this will allow for a consideration of how different outcomes may be influenced by sibship size. Health measures will include growth (i.e. height), number of disease symptoms/infections (as a measure of general well-being) and the mother's opinion of the study child's general health. All these measures have been taken at regular intervals and are suitable for longitudinal analysis. Educational measures are taken less regularly and only towards the older ages in the ALSPAC study. It is proposed that the results of maths tests taken at 3 intervals by the study child will be investigated. However, at this stage of research planning it is unclear about the appropriateness or accessibility of these data. Alternatively then, child development scores may be used to assess cognitive development. The study will also consider the type of schooling the child receives (private/non-private). Parental resources (socioeconomic class, mother's general health) is an obvious potential confounding factor, and so will also be incorporated to the models.
B. Can differences in parenting behaviour be identified as family size increases?
In attempt to further our understanding of the mechanisms by which high fertility impacts on child development, an estimation of the effect of number of siblings on parenting behaviour will also be included in the study. Taking advantage of the rich nature of the ALSPAC dataset, proposed measures of parenting behaviour will include; parenting scores of mother and father figure; freq of visits to places of interest; entertainment, to see friends and family; number of books owned, and the amount of television watched. Once again these measures have been taken at regular intervals and are thus suitable for longitudinal analysis.
C. Can socioecological differences explain variation in the magnitude of "sibling competition" within the British population?
As discussed above, variation across population subgroups in the magnitude of sibship size effects has been suggested by several studies. Yet despite suggestions there has so far been little empirical testing of the socioecological factors that may lie behind this variation. The proposed study will investigate how measures of both kin and non-kin social support, and also parental wealth, relate to the magnitude of effects. Several proxies of kin support will be included: father presence/involvement with child, presence of grandparents; regularity maternal/paternal relatives seen; and grandparent/relative role in child care arrangements. Mother's membership of a close group of friends and opinion of neighbourhood will be included as proxies of non-kin social support. While standard measures of socioeconomic class and household income will be used to explore the influence of parental resources on the costs of high fertility.
D. Are higher costs of large family size on child development associated with lower actual fertility?
As a final research question, the study will consider how the costs of high fertility, in terms of child development outcomes, relate to the actual fertility decisions of the population. After identifying the relationship of social support and wealth to sibship size effects, a model of age-controlled fertility will be constructed entering these same socioecological factors. It is predicted that those socioecological conditions associated with larger costs of high fertility, in terms of child development (e.g. low social support/ high wealth), will be strong predictors of lower actual fertility. This prediction is based on the assumption that even parents in modern societies adaptively track the effects of parental investment on child development outcomes and respond accordingly.
4. Relevant Qualifications
1. Bachelor of Science (BSc) Hons, Biology University College London, 2003
2. Master of Science (MSc), Evolutionary Psychology University of Liverpool, 2004
3. Ph.D Candidate in Biological Anthropology University College London, expected 2008
4. During the early period of my PhD I will follow courses in these specialised statistics and the analysis of longitudinal data at the Centre for Applied Social Surveys (CASS), University of Southampton and at the UCL Graduate School. Multi-level models and event history models will be employed in the analysis of the ALSPAC data. Event-history analysis can be used to accommodate two common features of longitudinal event histories: censored observations and time varying variables. The inclusion of time-varying covariates in particular is crucial, since the key variables of interest in the study are the presence of kin during childhood which can clearly change over time.
5. References
Alwin. (1991). Family of origin and cohort differences in verbal ability. . American Sociological Review, 56, 625-638. Ballard, T. J., & Neumann, C. (1995). The effect of malnutrition, parental literacy and household crowding on acute lower respiratory infections in young Kenyan children. Journal of Tropical Pediatrics, 41(8-13). Beise, J. (2004). The helping and the helpful grandmother - The role of maternal and paternal grandmothers in child mortality in the 17th and 18th century population of French Settlers in Quebec, Canada MPIDR Working Paper WP-2004-2004. Belmont, L., & Marolla, F. A. (1973). Birth order, family size, and intelligence. Science, 182, 1096-1101. Bentley, G. (1999). Aping Our Ancestors: Comparative Aspects of Reproductive Ecology. Evolutionary Anthropology, 7, 175-185. Birdsall, N. (1982). A cost of siblings. Child schooling in urban Colombia. Research in Population Economics, 2, 115-150. Blake, J. (1989). Family Size and Achievement. Los Angeles: University of California. Blau, P. M., & Duncan, O. D. (1967). The American occupational structure. New York: Wiley. Borgerhoff Mulder, M. (1998). The Demographic Transition: Are We Any Closer to an Evolutionary Explanation? . Trends in Ecology and Evolution, 13, 266-270. Chernochovsky, D. (1985). Socioeconomic and demographic aspects of school enrolment and attendance in rural Botswana. Economic Development and Cultural Change, 33, 319. Circirelli, V. G. (1978). The relationship between sibling structure to intellectual abilities and achievements. . Review of Education Research, 55, 353-386. Cronk, L. (1991). Human Behavioural Ecology. Annual Review of Anthropology, 20, 25-53. Demographiques, I. N. d. E. (1973). Enquete national sur le niveau intellectuel des enfants d'age scolaire [National report on the intellectual development of school age-age children]. Paris: Author, with Presses Universitaires de France. Downey, D. B. (1995). When Bigger is Not Better: Family Size, Parental Resources and Children's Educational Performance. American Sociological Review, 60(5), 746-761. Downey, D. B. (2001). Number of Siblings and Intellectual Development: The Resource Dilution Explanation. American Psychologist, 56(6/7), 497-504. Downey, D. B., & Neubauer, S. (1998). Is resource dilution inevitable? The association between number of siblings and educational outcomes across subgroups. . San Fransico, CA: Paper presented at the meeting of the American Soiological Association Draper, P. (1989). African Marriage Systems: perspectives from evolutionary ecology. . Ethology and Sociobiology, 10, 145-169. Eysenck, H. J., & Cookson, D. (1970). Personality in primary school children: Family background. British Journal of Educational Psychology, 40, 117-131. Featherman, D., & Hauser, R. (1978). Opportunity and change. New TYork: Academic Press. Gadgil, M., & Bossert, W. H. (1970). Life Historical Consequences of Natural Selection. . American Naturalist, 104, 1-24. Gibson, M. A., & Mace, R. (2005). Helpful grandmothers in rural Ethiopia: A study of the effect of kin on child survival and growth. Evolution and Human Behaviour, 26, 462-482. Gomes, M. (1984). Family size and educational attainment in Kenya. Population and Development Review, 10, 647-660. Guo, G., & VanWey, L. K. (1999). Sibship Size and Intellectual Development: Is the Relationship Causal? American Sociological Review, 64(2), 169-187. Hagen, E. H., Barret, C., & Price, M. E. (in press). Do Human Parents Face a Quantity-Quality Trade-off? Evidence from a Shuar Community. American Journal of Physical Anthropology, 128. Hagen, E. H., Hames, R. B., Craig, N. M., Lauer, M. T., & Price, M. E. (2001). Parental investment and child health in a yanomamo village suffering short-term food stress. Journal of Biosocial Science, 33, 503-528. Hawkes, K. (2003). Grandmothers and the evolution of human longevity. American Journal of Human Biology, 15, 380-400. Hesketh, T., Qu, J. D., & Tomkins, A. (2003). Health effects of family size: Cross sectional survey in Chinese adolescents. Archives of Disease in Childhood, 886, 467-471. Kaplan, H. (1996). A Theory of Fertility and Parental Investment in Traditional and Modern Human Societies. Yearbook of Physical Anthropology, 39, 91-135. Kaplan, H., Lancaster, J. B., Bock, J., & Johnson, S. (1995). Fertility and fitness among Alburquerque men: a competitive lbour market theory. In R. I. M. Dunbar (Ed.), Human Reproductive Decisions: Biological and Social Perspectives (pp. 96-136). London: Macmillan. Knodel, J., Havanon, N., & Sittitrai, W. (1990). Family size and the education of children in the context of rapid fertility decline. Population and Development Review, 28, 31-67. Kuo, H.-H. D., & Hauser, R. M. (1997). How does size of sibship matter? Family configuration and family effects on educational attainment. Social Science Research(26), 69-94. Lack, D. (1947). The significant of clutch size. Ibis, 89, 302-352. Lack, D. (1954). The natural regulation of animal numbers. Oxford: Clarendon Press. Lahdenpera, M., Lummaa, V., Helle, S., Tremblay, M., & Russell, A. F. (2004). Fitness benefits of prolonged post-reprodctive lifespan in women. Nature, 428, 178-181. Lam, D. (1986). The dynamics of populations growth, differential equality, and inequality American Economic Review, 76, 1103-1116. Lessells, C. M. (1991). The evolution of life histories. In J. R. Krebs & N. B. Davies (Eds.), Behavioural ecology (3rd ed) (pp. 32-68). Oxford: Blackwell. Low, B. (1990). Occupational status, landownership, and reproductive behaviour in 19th Century Sweden: Tuna Parish. American Anthropologist, 92, 457-468. Mace, R. (1996). Biased parental investment and reproductive success in Gabbra pastoralists. Behavioural Ecology and Sociobiology, 38, 75-81. Majoribanks, K. (1974). Academic achievement: Family size and social class correlates. In K. Majoribanks (Ed.), Environments for learning. Windsor, England: NFER Publishing. Marwole, F. (2001). Male contribution to diet and female reproductive success among foragers Current Anthropology, 42(755-760). Mauldon, J. (1990). The effect of marital disruption on children's health. Demography, 27(3), 431-446. Mercy, J. A., & Steelman, L. C. (1982). Familial influence on the intellectual attainment of children. American Sociological Review, 47, 532-542. Mock, R. R., & Leslie, J. (1986). Childhood malnutrition and schooling in Terai region of Nepal. Journal of Development Economics, 20, 33-52. Nanda, S. (1996). The impact of family milieu on the prevalence of protein-energy malnutrition in infants. Indian Journal of Maternal Child Health, 71, 20-23. Nisbet, J. D., & Entwistle, N. J. (1967). Intelligence and family size: 1949-1965. British Journal of Educational Psychology, 37, 188-193. Parcel, T. L., & Menaghan, E. G. (1994). Parent's job and children's lives. New York: Aldine De Gruyter. Perls, T. T., Alpert, L., & Fretts, R. C. (1997). Middle aged mothers live longer. Nature, 389(133-133). Perrusse, D. (1993). Cultural and reproductive success in idustrial societies: Testing the relationship at the proximate and ultimate levels. Brain and Behavioral Sciences, 16, 267-323. Quinlan, R. J. (2003). Father absence, parental care & female reproductive development. . Evolution and Human Behaviour, 24, 376-390. Rao, K., & Goplan, C. (1969). Nutrition and family size. Journal of Nutrition and Diet, 6, 258-266. Sear, R., Mace, R., & McGregor, I. A. (2000). Maternal grandmothers improve the nutritional status and survival of children in rural Gambia. Proceedings of the Royal Society of London, Series B, Biological Sciences, 267, 461-467. Sear, R., Mace, R., & McGregor, I. A. (2003). A life-history analysis of fertility rates in rural Gambia: evidence for trade-offs or phenotypic correlations? In J. Rodgers & H.-P. Kohler (Eds.), The Biodemography of Human Reproduction and Fertility (pp. 135-160). Boston: Kluwer Press. Sear, R., Steele, F., McGregor, I. A., & Mace, R. (2002). The effects of kin on female fertility in rural Gambia. Evolution and Human Behaviour, 24, 25-42. Shavit, Y., & Pierce, J. (1991). Sibship size and educational attainment in nuclear and extended families. American Sociological Review, 56, 321-330. Smith, C. C., & Fretwell, S. D. (1974). The optimal balance between size and number of offspring. American Naturalist, 108, 499-506. Steelman, L., Powell, B., Werum, R., & Carter, S. (2002). Reconsidering the Effects of Sibling Configuration: Recent Advances and Challenges. Annual Review of Sociology, 28, 243-269. Steelman, L. C. (1985). A tale of two variables: A review of the intellectual consequences of sibship size and birth order. Review of Education Research, 55, 353-386. Tada, Y., Keiwkarnka, B., Pancharunti, N., & Charoonsawasdi, K. (2002). Nutritional status of the preschool children of the Klong Toey slum, Bangkok. Southeast Asian Journal of Tropical Medicine and Public Health, 33, 628-637. Turke, P. W. (1989). Evolution and the demand for children. Population and Development Review, 15, 61-90. Tymicki, K. (2004). Kin influence on female reproductive behavior: The evidence from reconstitution of the Bejsce parish registers, 18th to 20th centuries, Poland. American Journal of Human Biology 16, 508-522. Vining, D. R. J. (1986). Social versus reproductive success: the central theoretical problem of human sociobiology. Behaviour and Brain Sciences, 9(167-216). Voland, E. (1990). Differential reproductive success within the Krummhorn population (Germany, 18th and 19th centuries). Behavioural Ecology and Sociobiology, 26, 65-72. Voland, E. (1998). Evolutionary Ecology of Human Reproduction. Annual Review of Anthropology, 27, 347-374. Westendorp, R. G. J., & Kirkwood, T. B. L. (1998). Human longevity at the cost of reproductive success. Nature, 396, 743-746. Williams, G. C. (1966). Natural selection, the costs of reproduction, and a refinement of Lack's principle. . American Naturalist, 100, 687-690. Winterhalder, B., & Smith, E. A. (2000). Analyzing Adaptive Strategies: Human Behavioural Ecology at 25. Evolutionary Anthropology, 9, 51-72. Wofle, B., & Behrman, J. (1982). Determinants of child mortality, health, and nutrition in a developing country. Journal of Development Economics, 11, 163-193. Zajonc, R. B., & Markus, G. B. (1975). Birth order and intellectual development. Psyhcological Review, 82(74-88).