UK Millennium Cohort Study Research Articles

Ethnic differences in height growth trajectories and early life factors: findings from the UK Millennium Cohort Study

Height growth is an important biomarker for early life exposures that influence later disease risk. Previous studies show that ethnic minority children in the UK tend to be born lighter but experience more rapid infancy growth than White peers. However, whether subsequent child-to-adolescent growth differs by ethnic group is insufficiently understood. We used the data from 15,239 singletons in the UK Millennium Cohort Study and applied mixed-effects cubic growth models to examine ethnic differences in height trajectories between 3y and 14y. Models were subsequently adjusted for potential early life explanatory factors. Compared with White counterparts, South Asian children had lower birthweight and shorter parents on average, but were slightly taller at 3y by 0.5cm [95% CI: 0.2–0.9] and had comparable childhood and adolescent trajectories, except that girls had a slower growth in adolescence. Height of South Asians relative to White children increased after adjusting for birthweight (taller by 1.3cm at 3y). Black African/Caribbeans were taller than White children at all ages between 3y and 14y (at 3y boys: 2.2cm, 1.2–2.7; girls: 3.2cm, 2.6–3.8) with height differences widening in childhood and reducing in adolescence. Adjustment for potential explanatory factors did not alter these differences. Despite having lower birthweight, contemporary UK South Asian children had comparable child-to-adolescent growth as White children. Black African/​Caribbeans were considerably taller than other ethnic groups. Future research is needed in understanding the role of genetic and other environmental factors (such as diet) in these distinct growth patterns across ethnic groups and their health implications.

Family Income Gradients in Adolescent Obesity, Overweight and Adiposity Persist in Extremely Deprived and Extremely Affluent Neighbourhoods but Not in Middle-Class Neighbourhoods: Evidence from the UK Millennium Cohort Study.

We investigated whether family income gradients in obesity, overweight, and adiposity persist at geographic-level deprivation quintiles using a nationally representative cohort of UK adolescents. Data from 11,714 eligible adolescents from the sixth sweep of the Millennium Cohort Study (14 years old) were analysed in this study. The International Obesity Task Force age- and sex-specific thresholds were used to define obesity and overweight. Self-reported family income was standardized using the Organisation for Economic Co-operation and Development (OECD)’s equivalised income scale. Geographic-level deprivation was defined by the index of multiple deprivation 2004. Results showed that the prevalence of obesity and overweight was 8.0% and 27.2%, respectively. Mean percentage body fat was 16.9% (standard error, SE = 0.2%) in male and 27.3% (SE = 0.1%) in female adolescents. Risk of obesity, overweight, and adiposity increased with decreasing family income quintiles (p for trend <0.001). After stratifying by geographic-level deprivation quintiles, a U-shaped association emerged, whereby family income gradients in the risk of adolescent obesity and adiposity persisted in extremely affluent and extremely deprived neighbourhoods but attenuated to non-significance in middle-class neighbourhoods. These results focus on the findings from England. Recognition of the persistence of inequalities in the risk of obesity in the most deprived and affluent neighbourhoods may be necessary in planning public health resources and interventions.

Children's behavioural problems and its associations with socioeconomic position and early parenting environment: findings from the UK Millennium Cohort Study.

To investigate behavioural problems throughout childhood and adolescent, and its relationship with socioeconomic position (SEP) and early parenting environment. Using data from the Millennium Cohort Study conducted in the UK, behavioural problems of 14 452 children were analysed using a growth curve model. The children were followed from birth to adolescence, and their behavioural problems were measured by the Strengths and Difficulties Questionnaire (SDQ). The SDQ was sub-scaled into externalising and internalising problems. After assessing the general trajectory of children's behavioural problems, variables representing SEP and parenting environments were introduced to the model to analyse the association with children's outcomes. Overall, children's trajectories in externalising problems showed a decreasing trend while internalising problems increased as they aged. Household income and maternal education in early childhood were independently associated with children's behavioural problems, while the association for maternal occupation was significantly weaker. Positive early parenting environments attenuated the association between SEP and children's behavioural problems. Also, with regards to children's behavioural problems, positive parenting explained more variance between children compared to SEP. Favourable parent-child relationship buffered the income gradient in children's behavioural problems during early childhood, and although this buffering effect did not last until adolescence, those who had good parent-child relationships developed better outcomes regardless of their SEP. The results of the study emphasise the importance of a positive early parenting environment for improving and reducing the socioeconomic gap in children's behavioural problems and encourages policies to promote better parenting circumstances.

Kin-based alloparenting and infant hospital admissions in the UK Millennium cohort

Abstract Background and objectives Kin-selected altruism is an evolutionary explanation for why biological kin other than parents are willing childcare providers or alloparents. Kin alloparents may increase lineage fitness by reducing maternal energy depletion and improving child survival through childcare activities. The aim of this research was to apply the hypothesis that kin-based alloparental care has benefits for child health in a western, educated, industrialized, rich, democratic context. Methodology The hypothesis was tested using the first sweep of the UK Millennium Cohort Study (n = 18 552 infants). The outcome was number of hospitalizations by age 9 months, and the main predictors were kin-based alloparental care during work hours, socioeconomic position and infant health-related variables and their interactions with kin-based alloparenting. Analysis of hospitalizations was carried out using negative binomial regression. Results Kin alloparents were primary day carers in 17% of households. Infants whose main care arrangement during work hours was with kin allocarers had statistically significantly fewer hospitalizations than infants in all other care arrangements combined (Incidence rate ratio = 0.86, P &amp;lt; 0.03), and when contrasted with maternal day care (Incidence rate ratio = 0.79, P &amp;lt; 0.02). Conclusions and implications Kin-based allocare was associated with about a 15% reduction in the risk of infant hospitalization in the first 9 months. The difference appeared to be due in part to a difference in the risk of hospitalization for infectious diseases. Sensitivity analyses indicated that infants cared for by their mother during the day rather than in day-care facilities were most at risk of hospitalization compared with those in kin-based care. Lay summary Modern industrialized societies are generally characterized by nuclear family households, with grandparents and other extended family often living a considerable distance away. Studies carried out in societies which have not undergone the fragmentation of extended families have shown that grandmothers and other biological kin reduce infant mortality, most likely because they distribute the burden of infant care so that it does not fall exclusively on the mother. Here, the hypothesis that grandparental and other family care would be beneficial for infant health in the contemporary UK was testing using the UK Millennium cohort. Infant health was measured as number of hospitalizations in the first 9 months from birth. The main findings were that kin-based infant care, which was most commonly by grandparents, was associated with a 15% reduction in the risk of hospitalization in infants up to 9 months of age. Further analysis suggested that the difference was larger for risk of infant hospitalization due to infectious diseases rather than non-infectious diseases. The results also suggested that the finding may have been driven by increased risk for infants of mothers caring for their infant during normal working hours with no other help, such as from the father or pay-for day-care.

Distinct patterns of socio-economic disparities in child-to-adolescent BMI trajectories across UK ethnic groups: A prospective longitudinal study.

SummaryBackgroundIn many high‐income countries, body mass index (BMI)/obesity levels are inversely associated with socio‐economic position (SEP). Little is known whether socio‐economic patterns in BMI trajectories throughout childhood differ by ethnicity, especially in the United Kingdom.ObjectivesTo investigate socio‐economic disparities in child‐to‐adolescent BMI trajectories and risks of overweight and obesity during adolescence across ethnic groups.MethodsMixed‐effects fractional polynomial and multinomial regression models were applied to estimate socio‐economic differences in BMI trajectories (3‐14 years) and risk of overweight/obesity at 14 years, respectively, in the UK Millennium Cohort Study (n = 15 996). Analysis was stratified by ethnicity.ResultPoverty was associated with higher BMI in children of White and South Asian origins, with a small difference at 3 years, which widened with age to 0.75 kg/m2 (95% CI, 0.59‐0.91) and 0.77 kg/m2 (0.26‐1.27) at 14 years for the White and South Asian groups, respectively. There was a reverse income‐BMI association in children of Black (African‐Caribbean) origin with the poverty group having a lower BMI (−0.37 kg/m2 [−0.71 to ‐0.04] at 5 years; −0.95 kg/m2 [−1.79 to −0.11] at 14 years). These patterns also presented with maternal education as a SEP indicator and for obesity at 14 years.ConclusionsSocio‐economic advantage may not be universally associated with lower BMI, which should be considered when planning obesity interventions. The positive SEP‐BMI association in children of Black origin requires replication and merits further investigation into underpinning mechanisms.

Could Greater Physical Activity Reduce Population Prevalence and Socioeconomic Inequalities in Children's Mental Health Problems? A Policy Simulation.

One in four children 5-16 years (y) of age shows signs of mental health problems in the United Kingdom; risk is higher in economically disadvantaged groups. Greater physical activity is associated with lower risk of internalizing problems such as depression and anxiety. We simulated the potential impact of population-wide physical activity interventions on overall prevalence of internalizing problems, and by family income. Interventions were based on the World Health Organization (WHO) children's target of 60 minutes (min) of moderate-to-vigorous physical activity per day and trial evidence. Data were from the UK Millennium Cohort Study, a population-representative cohort of children born in 2000-2002. Household income (5 y) was the exposure; internalizing problems (outcome) were measured using the Strengths and Difficulties Questionnaire (11 y). Of 18,296 singletons, 6,497 had accelerometer physical activity data (mediator, manipulated to simulate interventions) at 7 y. We predicted probabilities of outcome according to exposure in marginal structural models, weighted for attrition and confounding, and adjusted for observed mediator. We then re-estimated probabilities in different physical activity intervention scenarios, assessing income inequalities in internalizing problems with risk ratios (RRs) and differences (RDs) according to income quintile. Simulating universal achievement of the WHO target led to little change in prevalence (10% [95% CI = 8%, 12%]) and socioeconomic inequalities in internalizing problems; RR: 2.2 (1.1, 3.4); RD: 8% [5%,13%]). More modest increases in physical activity achieved weaker results. Our simulations suggest that large increases in moderate-to-vigorous physical activity in the United Kingdom would have little effect on prevalence and inequalities in child mental health problems.

In the best interests of children? The paradox of intensive parenting and children’s health

ABSTRACT The family environment and parental guidance are generally considered to be key drivers of children’s health behaviours. Parents, mostly mothers, have become a focal point of policies aimed at preventing children’s health and well-being problems (e.g. childhood obesity). The underlying intensive parenting ideology places significant pressure on parents (notably mothers), requiring them to spend a great deal of time, energy and money on their children’s health and well-being. Yet, the relationship between intensive parenting and children’s health might be paradoxical. While a clear positive relationship exists between parental childrearing styles and children’s physical health, the limited evidence in relation to psychological health suggests intensive parenting may negatively affect children’s wellbeing. Using data from the UK Millennium Cohort Study (MCS) we provide key insights into the relationship between parenting styles and children’s physical and psychological well-being. We analytically distinguish three types of parenting styles (intensive parenting, neglectful parenting, and ‘intermediate’ parenting), and compare children’s self-reported health, well-being and self-esteem by parenting style. The findings show that parenting styles may differentially affect children’s physical and psychological health in nuanced ways. Public health and social policy implications of the role of parenting in children’s health and wellbeing are discussed. The conceptualisation of parenting styles and the relationship with children’s health, however, requires further exploration, which we discuss in the conclusion.

Reading for pleasure in childhood and adolescent healthy behaviours: Longitudinal associations using the Millennium Cohort Study

Leading a heathy lifestyle in adolescence is vital to individual health in later life. Drawing upon various existing theories, this study hypothesised that engagement in reading for pleasure may enhance healthy behaviours amongst young people. Data were analysed from 11,180 children in the UK Millennium Cohort Study and logistic regressions were used to examine the association between reading frequency at age 11 and health behaviours at age 14. Reading most days was associated with lower odds of trying a cigarette and alcohol and a higher likelihood of having two portions of fruit per day independent of confounding factors. However, spending more time reading was associated with less time spent engaging in moderate to vigorous physical activity. Our findings suggest the importance of further studies exploring the potential health benefits of reading amongst young people.

Associations between mental health competence and indicators of physical health and cognitive development in eleven year olds: findings from the UK Millennium Cohort Study

BackgroundPositive mental health may support healthy development in childhood, although few studies have investigated this at a population level. We aimed to construct a measure of mental health competence (MHC), a skills-based assessment of positive mental health, using existing survey items in a representative sample of UK children, and to investigate its overlap with mental health difficulties (MHD), socio-demographic patterning, and relationships with physical health and cognitive development.MethodsWe analysed the UK Millennium Cohort Study (MCS) when children were aged 11 years. Maternal (n = 12,082) and teacher (n = 6739) reports of prosocial behaviours (PS) and learning skills (LS) were entered into latent class models to create MHC measures. Using descriptive statistics, we examined relationships between MHC and MHD, and the socio-demographic patterning of MHC. Associations between MHC and physical health and cognitive development were examined with relative risk ratios [RRR] (from multinomial models): BMI status (healthy weight, overweight, obesity); unintentional injuries since age 7 (none, 1, 2+); asthma symptoms (none, 1, 2+); and tertiles of test scores for verbal ability, spatial working memory and risk-taking. Models were adjusted for potential confounding.ResultsFour MHC classes were identified [percentages for maternal and teacher reports, respectively]: high MHC (high PS, high LS) [37%; 39%], high-moderate MHC (high PS, moderate LS) [36%; 26%]; moderate MHC (moderate PS, moderate LS) [19%; 19%]; low MHC (moderate PS, low LS) [8%; 16%]. Higher MHC was less common in socially disadvantaged children. While MHC and MHD were associated, there was sufficient separation to indicate that MHC captures more than the absence of MHD. Compared to children with high MHC, those in other MHC classes tended to have poorer physical health and cognitive development, particularly those with low MHC or high-moderate MHC. For example, children with maternal-report Low MHC were more likely to have experienced 2+ unintentional injuries (RRR: 1.5 [1.1–2.1]) and to have lower verbal ability scores (RRR: 2.5 [1.9–3.2]). Patterns of results were similar for maternal- and teacher-report MHC.ConclusionMHC is not simply the inverse of MHD, and high MHC is associated with better physical health and cognitive development. Findings suggest that interventions to improve MHC may support healthy development, although they require replication.

Could increasing income in lone-parent households reduce inequality in child mental health problems?

Abstract Half of lone-parent families in the UK live in relative poverty (income &amp;lt;60% national median) compared to a quarter of two-parent families. Family hardship is associated with increased risk of child mental health problems (CMHP). Using data from the UK Millennium Cohort Study (∼18,000 children born 2000-02), we investigated whether equalising income between lone- and two-parent households could reduce prevalence and inequality in CMHP. Exposure was family structure (lone-/ two-parent household) at 9 months; mediator was equivalised weekly household income at 3 years(y); outcome was parent-report CMHP at 5y (Strengths and Difficulties Questionnaire; normal/ borderline-abnormal). The analytic sample comprised 11,193 children. We modelled the relationship between family structure, income and CMHP in logistic marginal structural models, weighted for attrition to MCS at 5y, and adjusted for baseline and intermediate confounding. Prevalence of CMHP was assessed overall and according to family structure. Differences between lone and two-parent households were represented by risk ratios (RRs) and differences (RDs) [95% CIs]. We modelled a hypothetical increase in income for all lone-parent households, so that median income was equalised between lone- and two-parent households, and re-estimated prevalence, RRs and RDs. Prevalence of CMHP was 8.5%. Children from lone-parent households were more likely to exhibit CMHP (RR 1.73[1.28-2.19]; RD 5.70[2.44-8.97]). Equalising income reduced prevalence (8.2%), and differences in CMHP by family structure (RR, 1.37[0.90-1.83]; RD, 2.86[-0.06-6.31]). Sensitivity analyses showed that associations between exposure, mediator and outcome were comparable in more recent MCS sweeps, indicating that these relationships still hold today. Inequalities in CMHP between lone- and two-parent families in the UK are large. Levelling up income for lone-parents households could reduce differences in child mental health problems related to family structure. Key messages Inequalities in CMHP between lone- and two-parent families in the UK are large. Levelling up income for lone-parents households could reduce differences in child mental health problems related to family structure.

Pathways to inequalities in child mental health: a causal mediation analysis of evidence from two national birth cohorts

BackgroundPathways linking socioeconomic circumstances to child mental health problems are poorly understood. We used two national birth cohorts to assess how social inequalities in child mental health problems were mediated by perinatal factors, childhood illness, and maternal mental health. MethodsWe applied causal mediation analysis to longitudinal data from the Danish National Birth Cohort (DNBC; n=26251) and the UK Millennium Cohort Study (MCS; n=13112). The exposure was maternal education at birth, a measure of childhood socioeconomic circumstances. The outcome, child mental health problems, was measured by the Strength and Difficulty Questionnaire at age 11 years with country-specific cut-offs. We estimated the natural direct and indirect effect and total effect of socioeconomic circumstances on mental health problems, calculating the relative risk across the socio-economic hierarchy (relative index of inequality, RII). Using natural effect models, we calculated the proportion mediated (PM) via three blocks of mediators sequentially whilst adjusting for confounding. Three potentially mediating blocks were perinatal factors (smoking or alcohol use during pregnancy, low birthweight, and gestational age), childhood illness, and maternal mental health, measured up to child age 7 years. FindingsAt age 11 years, 3·7% (n=1375) and 9% (n=1130) of children had mental health problems in Denmark (DBNC: mean age 11·4 years [SD 0·6]; 50% boys) and the UK (MCS: 10·7 years [0·5]; 51% boys), respectively. Lower socioeconomic circumstances were associated with mental health problems for both cohorts (DNBC: RII=5·9, 95% confidence interval 4·6–7·6]; MCS: RII=4·3, 95% CI 3·3–5·5). In DNBC, perinatal factors mediated 14·6% (95% CI 9.7–19.4) of social inequalities in MHP. Including childhood illness in the model barely increased PM, and addition of maternal mental health increased PM to 15·5% (95% CI 9·8–21·2). In MCS, perinatal factors mediated 10·2% of the association (95% CI 4·5–15·9). Addition of childhood illness barely increased PM, but addition of maternal mental health tripled PM to 32·2% (25·4–39·1). InterpretationOur findings suggest that UK children are more at risk of mental health problems than are Danish children. Social inequalities in such problems at age 11 year are partly explained by perinatal factors in the UK and Denmark. Maternal mental health might be an important mediator of social inequalities in child mental health problems in the UK, but not in Denmark. FundingETCL and DTR are funded by the MRC on a Clinician Scientist Fellowship (MR/P008577/1). TL, KS-L and A-MNA were funded by University of Copenhagen. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Poverty dynamics and health in late childhood in the UK: evidence from the Millennium Cohort Study

ObjectiveTo assess the prevalence of different trajectories of exposure to child poverty and their association with three indicators of adolescent physical and mental health in UK children.MethodsWe analysed data on...

The codevelopment of internalizing symptoms, externalizing symptoms, and cognitive ability across childhood and adolescence.

Cognitive ability, externalizing symptoms, and internalizing symptoms are correlated in children. However, it is not known why they combine in the general child population over time. To address this, we used data on 17,318 children participating in the UK Millennium Cohort Study and followed-up five times between ages 3 and 14 years. We fitted three parallel-process latent growth curve models to identify the parallel unfolding of children's trajectories of internalizing symptoms, externalizing symptoms, and cognitive ability across this period. We also examined the effects of time-invariant (ethnicity, birth weight, maternal education and age at birth, and breastfeeding status) and time-varying covariates (maternal psychological distress and socioeconomic disadvantage) on the growth parameters of the trajectories. The results showed that the intercepts of the trajectories of cognitive ability and, particularly, externalizing symptoms were inversely correlated. Their linear slopes were also inversely correlated, suggesting parallel development. Internalizing symptoms were correlated positively with externalizing symptoms and inversely (and more modestly) with cognitive ability at baseline, but the slope of internalizing symptoms correlated (positively) only with the slope of externalizing symptoms. The covariates predicted 9% to 41% of the variance in the intercepts and slopes of all domains, suggesting they are important common risk factors. Overall, it appears that externalizing symptoms develop in parallel with both cognitive ability and internalizing symptoms from early childhood through to middle adolescence. Children on an increasing trajectory of externalizing symptoms are likely both increasing in internalizing symptoms and decreasing in cognitive skills as well, and are thus an important group to target for intervention.

Multiple Imputation with Survey Weights: A Multilevel Approach

Abstract Multiple imputation is now well established as a practical and flexible method for analyzing partially observed data, particularly under the missing at random assumption. However, when the substantive model is a weighted analysis, there is concern about the empirical performance of Rubin’s rules and also about how to appropriately incorporate possible interaction between the weights and the distribution of the study variables. One approach that has been suggested is to include the weights in the imputation model, potentially also allowing for interactions with the other variables. We show that the theoretical criterion justifying this approach can be approximately satisfied if we stratify the weights to define level-two units in our data set and include random intercepts in the imputation model. Further, if we let the covariance matrix of the variables have a random distribution across the level-two units, we also allow imputation to reflect any interaction between weight strata and the distribution of the variables. We evaluate our proposal in a number of simulation scenarios, showing it has promising performance both in terms of coverage levels of the model parameters and bias of the associated Rubin’s variance estimates. We illustrate its application to a weighted analysis of factors predicting reception-year readiness in children in the UK Millennium Cohort Study.

When richer doesn't mean thinner: Ethnicity, socioeconomic position, and the risk of child obesity in the United Kingdom.

A range of studies report a robust association between family socioeconomic position and the prevalence of child overweight/obesity. On average, children from poorer backgrounds are more likely to be overweight/obese than children from more advantaged families. However, a small number of US studies have shown that, for ethnic minority children, the association is either nonexistent or reversed. We test if the link between socioeconomic position and child overweight/obesity at age 7 is heterogeneous in the United Kingdom where rates of obesity are particularly high for some groups of ethnic minority children. We use nationally representative data from the UK Millennium Cohort Study as well as descriptive analyses and logistic regression models. Poorer White children are at higher risk of overweight/obesity than higher income White children. However, socioeconomic disparities are reversed for Black African/Caribbean children and nonexistent for children of Indian and Pakistani/Bangladeshi origin. Moreover, the health behaviours that explain socioeconomic disparities in child overweight/obesity for the White group appear to be irrelevant in explaining differences by socioeconomic position for the Black Caribbean and African groups. We should be careful in assuming that higher socioeconomic position is protective against child overweight/obesity for all groups of the population. This study shows for the first time important variation by ethnicity in the link between socioeconomic position and child overweight/obesity - and in the underlying mechanisms linking them - in the United Kingdom.

Do Conduct Problem Pathways Differ for Black and Minority Ethnic Children in the UK? An Examination of Trajectories from Early Childhood to Adolescence

A substantial body of evidence has examined developmental pathways into and out of conduct problems. However, there is a dearth of research examining whether the same conduct problem pathways are evident in minority ethnic, as in white, populations. Drawing on the UK Millennium Cohort Study (MCS), a nationally representative longitudinal study of children born between 2000 and 2002, this study examines differences in group-based trajectories of conduct problems according to broad categories of ethnicity. Using pathways identified in a prior study (n = 17,206, 49% female, 18% ethnic minority), including persistently high (8%), childhood-limited (23%), adolescent-onset (13%), and low (56%), significant ethnic differences were found. As a result, trajectories of conduct problems were identified separately for Asian, black, mixed ethnicity, and white children. For Asian, black, and mixed ethnicity children, three trajectories were identified: persistently high, childhood-limited, and low, but not adolescent-onset. Although these pathways have similar labels, their patterns and shapes seem to differ among the three ethnic groups. For white children, the same four trajectory groups were identified as in the prior study. Risk factors also differed among the groups according to ethnicity, although a worse child-parent relationship was a significant predictor of the higher problem trajectories for all ethnic groups. Overall, the findings suggest that black and minority ethnic children may follow different developmental pathways of conduct problems than white children, particularly during adolescence, having implications for service use and early intervention.

Mind the gap: The health advantages that accompany parental marriage vary by maternal nativity

Using data from the UK Millennium Cohort Study (MCS), we examine whether and how the health benefits of having two biological parents in a continuous marital relationship vary by maternal nativity and ethnicity, comparing UK-born White mothers with: (1) White mothers born in wealthy countries; (2) ethnic minority mothers from South Asia; and (3) ethnic minority mothers born in Africa. Making novel use of classification and regression tree (CART) methods, we examine whether marital status is a uniform marker of economic advantage or better health-related behaviours across the four maternal nativity and ethnic groups. The findings, which indicate that the health-related advantages associated with parental marriage are not uniform across the four nativity and ethnic groups, have implications for future research on family gaps in well-being and the socio-economic determinants of health.

Social media use and adolescent sleep patterns: cross-sectional findings from the UK millennium cohort study

ObjectivesThis study examines associations between social media use and multiple sleep parameters in a large representative adolescent sample, controlling for a wide range of covariates.DesignThe authors used cross-sectional data from...

Prevalence and Correlates of Meeting Sleep, Screen-Time, and Physical Activity Guidelines Among Adolescents in the United Kingdom

This analysis of the UK Millennium Cohort Study examines the associations between sleep, physical activity, and screen time in adolescents aged 14 years in the United Kingdom.

A longitudinal birth cohort study of early life conditions, psychosocial factors, and emerging adolescent sexual orientation

This study tested whether previously reported associations between early life factors and later adolescent sexual orientation could be replicated in another prospective birth cohort, the UK Millennium Cohort Study (MCS). We used data on 9,795 youth from the MCS. Emerging sexual orientation was assessed using measures of sexual attraction to males and females in separate items at 14years. Factors including birthweight, breastfeeding, sibling composition, parental ages, maternal psychopathology, parent-child relationship, and contextual risks were separated into three developmental periods: prenatal (n=5 factors), before 7years (n=6 factors), and after 7years (n=5 factors). We controlled for handedness as a putative marker of prenatal androgen exposure and the possibility of mischievous responding statistically. Girls with greater maternal psychological distress since age 7 and greater pubertal body mass index were more likely to be nonheterosexual but the effect sizes were very small. Among boys there were no significant associations between any early life conditions and later sexual orientation. However, focusing on effect sizes rather than significance levels, there were small associations between preterm birth and nonheterosexuality. The results offer further evidence that psychosocial influences in the development of adolescent sexual orientation are weak or non-existent.