Phenotypic Associations With the HMOX1 GT(n) Repeat in European Populations

Heme oxygenase 1 is a key enzyme in the management of heme in humans. A GT(n) repeat length in the heme oxygenase 1 gene (HMOX1) has been widely associated with a variety of phenotypes, including susceptibility to and outcomes in diabetes, cancer, infections, and neonatal jaundice. However, studies have generally been small and results inconsistent. In this study, we imputed the GT(n) repeat length in participants from 2 UK cohort studies (the UK Biobank study (n = 463,005; recruited in 2006-2010) and the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 937; recruited in 1990-1991)), with the reliability of imputation tested in other cohorts (1000 Genomes Project, Human Genome Diversity Project, and Personal Genome Project UK). Subsequently, we measured the relationship between repeat length and previously identified associations (diabetes, chronic obstructive pulmonary disease, pneumonia, and infection-related mortality in the UK Biobank; neonatal jaundice in ALSPAC) and performed a phenomewide association study in the UK Biobank. Despite high-quality imputation (correlation between true repeat length and imputed repeat length > 0.9 in test cohorts), clinical associations were not identified in either the phenomewide association study or specific association studies. These findings were robust to definitions of repeat length and sensitivity analyses. Despite multiple smaller studies identifying associations across a variety of clinical settings, we could not replicate or identify any relevant phenotypic associations with the HMOX1 GT(n) repeat.

The dietary approaches to stop hypertension (DASH) dietary pattern in childhood in relation to cardiometabolic risk in adolescence and early adulthood in the ALSPAC birth cohort

OBJECTIVE

To investigate the relationship between the dietary approaches to stop hypertension (DASH)-style dietary patterns in childhood and cardiometabolic risk (CMR) in adolescence/early adulthood.

DESIGN

Data were obtained from the Avon Longitudinal Study of Parents and Children (ALSPAC) prospective cohort. Diet diary data collected at 7, 10 and 13 years were used to calculate DASH-style diet scores (DDS). Multivariable linear regression models were used to investigate the associations between the DDS at 7, 10 and 13 years and CMR scores, calculated at 17 and 24 years.

SETTING

The ALSPAC cohort included children born in south-west England in 1991-1992.

PARTICIPANTS

Children with complete dietary, covariate and cardiometabolic data at 17 (n 1,526) and 24 years (n 1,524).

RESULTS

A higher DDS at 7 and 10 years was negatively associated with CMR scores at 17 years (β = -0·64 (95 % CI -1·27, -0·006), Ptrend=0·027 for fifth v. first DDS quintile at 7 years; β = -0·73 (95 % CI -1·35, -0·12) and Ptrend=0·037 for fifth v. first DDS quintile at 10 years) and at 24 years (β = -0·92 (95 % CI -1·49, -0·34) Ptrend = 0·001 for fifth v. first DDS quintile at 7 years; β = -0·60 (95 % CI -1·20, -0·05) Ptrend = 0·092 for fifth v. first DDS quintile at 10 years). No associations were found between the DDS at 13 years and CMR score at 17 and 24 years.

CONCLUSION

Greater adherence with a DASH-style diet during childhood was associated with better cardiometabolic health in adolescence/adulthood in the ALSPAC cohort. The components of the DASH diet could be recommended to improve children's cardiometabolic health.

Is there an association between physical activity and lower urinary tract symptoms in adolescent girls? Results from the Avon Longitudinal Study of Parents and Children

INTRODUCTION AND HYPOTHESIS

Lower urinary tract symptoms (LUTS) are common among adolescent girls. Physical activity (PA) has been implicated as both a risk (high-impact PA) and protective factor (low-impact, moderate to vigorous intensity PA) for LUTS in adult women, but its role in adolescent girls is unclear. This study investigated the prospective association between physical activity and LUTS risk in adolescent girls.

METHODS

The sample comprised 3,484 female participants in the Avon Longitudinal Study of Parents and Children. Multivariate logistic regression models were used to examine daily minutes of moderate to vigorous PA (MVPA) at ages 11 and 15 years in relation to LUTS at ages 14 and 19 respectively. MVPA was assessed by 7-day accelerometer data. LUTS were assessed by questionnaire. MVPA were analyzed as continuous (minutes/day) and categorical variables (<10th percentile, 10-89th percentile, ≥90th percentile).

RESULTS

Prevalence of LUTS ranged from 2.0% for bedwetting to 9.5% for nocturia at age 14 and from 2.0% for straining to urinate to 35.5% for interrupted urine flow at age 19. Physical activity was not associated with LUTS at either time-point.

CONCLUSIONS

Given the prevalence of LUTS in female adolescent populations, although this study did not find an association with accelerometer-measured MVPA, other aspects of PA that may serve as risk or protective factors deserve investigation.

Continence Problems and Mental Health in Adolescents from a UK Cohort

BACKGROUND

Adolescents with continence problems experience unique threats to their psychological well-being, but long-term mental health sequelae are unknown.

OBJECTIVE

To examine prospective relationships between incontinence/lower urinary tract symptoms (LUTS) and mental health problems in young people.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study of young people (n = 7332: 3639 males and 3693 females) from a population-based sample was conducted.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We estimated the association between incontinence/LUTS and mental health outcomes using multivariable regression models adjusted for sex, socioeconomic position, developmental level, intelligence quotient, stressful life events, maternal psychopathology, body mass index, and emotional/behavioural problems.

RESULTS AND LIMITATIONS

Daytime wetting and voiding postponement showed the greatest number of associations with mental health problems. All incontinence subtypes/LUTS were associated with increased odds of generalised anxiety disorder (eg, odds ratio for daytime wetting = 3.01, 95% confidence interval [1.78, 5.09], p < 0.001) and/or higher anxiety scores. There was also evidence of associations with common mental disorder (eg, voiding postponement: 1.88 [1.46, 2.41], p < 0.001), depression (eg, urgency: 1.94 [1.19, 3.14], p = 0.008), depressive symptoms (eg, daytime wetting: 1.70 [1.13, 2.56], p = 0.01), self-harm thoughts (eg, voiding postponement: 1.52 [1.16, 1.99], p = 0.003), and disordered eating (eg, nocturia 1.72 [1.27, 2.34], p = 0.001). We are unable to generalise our results to minority ethnic groups, less affluent populations, and non-UK samples.

CONCLUSIONS

Young people with incontinence/LUTS are at an increased risk of mental health problems. Further research is needed to establish the direction of causality.

PATIENT SUMMARY

We looked at the association between continence problems and mental health outcomes in young people from a large population-based cohort. Young people with continence problems at the age of 14 yr were more likely to suffer from a range of mental health problems at the age of 18 yr, including common mental disorder, depression, anxiety, self-harm thoughts, and disordered eating. Paediatric continence clinics should address the mental health needs of young people and provide clear and effective care pathways to child and adolescent mental health services.

Exploring causality from observational data: An example assessing whether religiosity promotes cooperation

Causal inference from observational data is notoriously difficult, and relies upon many unverifiable assumptions, including no confounding or selection bias. Here, we demonstrate how to apply a range of sensitivity analyses to examine whether a causal interpretation from observational data may be justified. These methods include: testing different confounding structures (as the assumed confounding model may be incorrect), exploring potential residual confounding and assessing the impact of selection bias due to missing data. We aim to answer the causal question 'Does religiosity promote cooperative behaviour?' as a motivating example of how these methods can be applied. We use data from the parental generation of a large-scale (n = approximately 14,000) prospective UK birth cohort (the Avon Longitudinal Study of Parents and Children), which has detailed information on religiosity and potential confounding variables, while cooperation was measured via self-reported history of blood donation. In this study, there was no association between religious belief or affiliation and blood donation. Religious attendance was positively associated with blood donation, but could plausibly be explained by unmeasured confounding. In this population, evidence that religiosity causes blood donation is suggestive, but rather weak. These analyses illustrate how sensitivity analyses can aid causal inference from observational research.

Maternal postnatal depression and anxiety and the risk for mental health disorders in adolescent offspring: Findings from the Avon Longitudinal Study of Parents and Children cohort

OBJECTIVE

The impacts of postnatal psychiatric disorders on different types of mental health problems in offspring are unclear. We investigated the prospective associations of maternal postnatal depression, and anxiety, with offspring depression, anxiety, psychotic-like experiences and Borderline Personality Disorder symptoms, in adolescence, and examined whether these were independent of each other.

METHODS

Data were obtained from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. Maternal postnatal depression and anxiety at 8 weeks were measured using the Edinburgh Postnatal Depression Scale and Crown-Crisp Index, respectively. Offspring mental health outcomes were measured at 10-13 years old, using a variety of questionnaire-based and interview assessments. Logistic regression analyses were used to assess the associations between maternal postnatal risk factors and offspring mental health, and path analysis was used to investigate the pathways of maternal postnatal factors to adolescent offspring outcomes.

RESULTS

Data were available for 14,054 mothers with information reported on postnatal depression and 13,892 on postnatal anxiety. Logistic regression analyses found significant associations between maternal postnatal depression and offspring anxiety at 10 years old (odds ratio = 1.039, 95% confidence interval = [1.005, 1.073], p = 0.022) and between maternal postnatal anxiety and offspring psychotic experiences at 12/13 years old (odds ratio = 1.042, 95% confidence interval = [1.008, 1.077], p = 0.016). These significant associations remained after applying path analyses, when we controlled for potential offspring psychopathological overlay.

CONCLUSION

These findings suggest that mothers with postnatal depression are more likely to have offspring with anxiety at 10 years old, and that mothers with postnatal anxiety are more likely to have offspring with psychotic experiences at 12/13 years old. Our findings suggest specific pathways in the association between postnatal anxiety/depression and offspring mental health and contribute to the importance of identifying mothers and their offspring with increased vulnerability to adverse outcomes resulting from postnatal mental health disorders.

Mode of delivery and maternal sexual wellbeing: A longitudinal study

OBJECTIVES

To investigate the association between mode of delivery and subsequent maternal sexual wellbeing.

DESIGN

Prospective birth cohort study.

SETTING

Avon (in Bristol area), UK.

POPULATION

Participants in the Avon Longitudinal Study of Parents and Children (ALSPAC).

METHODS

Mode of delivery was abstracted from obstetric records and sexual wellbeing measures were collected via a self-report questionnaire. Missing data were imputed using multiple imputation, and ordinal logistic regression models for ordered categorical outcomes were adjusted for the covariates maternal age at delivery, pre-pregnancy body mass index, diabetes during pregnancy, socio-economic position, parity, depression and anxiety.

MAIN OUTCOME MEASURES

Sexual enjoyment and frequency at four time points postpartum (between 33 months and 18 years) and two types of sex-related pain (pain in the vagina during sex and elsewhere after sex) at 11 years postpartum.

RESULTS

We found no association between mode of delivery and sexual enjoyment (e.g. adjusted odds ratio [OR] 1.11, 95% confidence interval [95% CI] 0.97-1.27 at 33 months) or sexual frequency (OR 0.99, 95% CI 0.88-1.12 at 33 months). Caesarean section was associated with an increased odds of pain in the vagina during sex at 11 years postpartum as compared with vaginal delivery in the adjusted model (OR 1.74, 95% CI 1.46-2.08).

CONCLUSIONS

These findings provide no evidence supporting associations between caesarean section and sexual enjoyment or frequency. However, mode of delivery was shown to be associated with dyspareunia, which may not be limited to abdominal scarring.

Combining Longitudinal Data From Different Cohorts to Examine the Life-Course Trajectory

Longitudinal data are necessary to reveal changes within an individual as he or she ages. However, rarely will a single cohort study capture data throughout a person's entire life span. Here we describe in detail the steps needed to develop life-course trajectories from cohort studies that cover different and overlapping periods of life. Such independent studies are probably from heterogenous populations, which raises several challenges, including: 1) data harmonization (deriving new harmonized variables from differently measured variables by identifying common elements across all studies); 2) systematically missing data (variables not measured are missing for all participants in a cohort); and 3) model selection with differing age ranges and measurement schedules. We illustrate how to overcome these challenges using an example which examines the associations of parental education, sex, and race/ethnicity with children's weight trajectories. Data were obtained from 5 prospective cohort studies (carried out in Belarus and 4 regions of the United Kingdom) spanning data collected from birth to early adulthood during differing calendar periods (1936-1964, 1972-1979, 1990-2012, 1996-2016, and 2007-2015). Key strengths of our approach include modeling of trajectories over wide age ranges, sharing of information across studies, and direct comparison of the same parts of the life course in different geographical regions and time periods. We also introduce a novel approach of imputing individual-level covariates of a multilevel model with a nonlinear growth trajectory and interactions.

Precursors and correlates of transient and persistent longitudinal profiles of psychotic experiences from late childhood through early adulthood

BACKGROUND

Psychotic experiences are reported by 5-10% of young people, although only a minority persist and develop into psychotic disorders. It is unclear what characteristics differentiate those with transient psychotic experiences from those with persistent psychotic experiences that are more likely to be of clinical relevance.

AIMS

To investigate how longitudinal profiles of psychotic experiences, created from assessments at three different time points, are influenced by early life and co-occurring factors.

METHOD

Using data from 8045 individuals from a birth cohort study, longitudinal profiles of psychotic experiences based on semi-structured interviews conducted at 12, 18 and 24 years were defined. Environmental, cognitive, psychopathological and genetic determinants of these profiles were investigated, along with concurrent changes in psychopathology and cognition.

RESULTS

Following multiple imputations, the distribution of longitudinal profiles of psychotic experiences was none (65.7%), transient (24.1%), low-frequency persistent (8.4%) and high-frequency persistent (1.7%). Individuals with high-frequency persistent psychotic experiences were more likely to report traumatic experiences, other psychopathology, a more externalised locus of control, reduced emotional stability and conscientious personality traits in childhood, compared with those with transient psychotic experiences. These characteristics also differed between those who had any psychotic experiences and those who did not.

CONCLUSIONS

These findings indicate that the same risk factors are associated with incidence as with persistence of psychotic experiences. Thus, it might be that the severity of exposure, rather than the presence of specific disease-modifying factors, is most likely to determine whether psychotic experiences are transient or persist, and potentially develop into a clinical disorder over time.

Intrapersonal and Interpersonal Functions as Pathways to Future Self-Harm Repetition and Suicide Attempts

Background: Research has identified functions of non-suicidal self-harm/self-injury (NSSH) but whether functions change over time, from adolescence to early adulthood, or predict the continuation of the behavior prospectively remains unclear. This study aimed to prospectively explore whether intrapersonal and interpersonal NSSH functions in adolescence predict repetition of self-harm (regardless of suicidal intent) and incident suicide attempts in early adulthood.

Methods: Participants were 528 individuals with NSSH at age 16 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), a population-based birth cohort in the UK. Descriptive statistics were used to explore changes in functions over time from age 16 to 21, and logistic regression used to examine associations between NSSH functions and repeat self-harm and suicide attempts at age 21, 24, and 25 years.

Findings: The majority of 16-year-olds with NSSH endorsed intrapersonal (e.g., affect regulatory) functions only (73% at 16 years and 64% at 21 years). Just under half of adolescents (42%) and three quarters of 21 years olds reported more than one function simultaneously. A greater number of intrapersonal functions at 16 years independently predicted future repetition of self-harm at ages 21–25 years, over and above interpersonal functions (OR = 1.46, 95% CI 1.06–2.01). Interpersonal functions during adolescence did not predict repeat self-harm or suicide attempts in adulthood.

Discussion: Our findings suggest that intrapersonal but not interpersonal NSSH functions are a prospective risk factor for future self-harm and might also predict incident suicide attempts. The results highlight the central role of underlying affective difficulties and motivations in self-harm maintenance.

A Structured Approach to Evaluating Life-Course Hypotheses: Moving Beyond Analyses of Exposed Versus Unexposed in the -Omics Context

The structured life-course modeling approach (SLCMA) is a theory-driven analytical method that empirically compares multiple prespecified life-course hypotheses characterizing time-dependent exposure-outcome relationships to determine which theory best fits the observed data. In this study, we performed simulations and empirical analyses to evaluate the performance of the SLCMA when applied to genomewide DNA methylation (DNAm). Using simulations (n = 700), we compared 5 statistical inference tests used with SLCMA, assessing the familywise error rate, statistical power, and confidence interval coverage to determine whether inference based on these tests was valid in the presence of substantial multiple testing and small effects-2 hallmark challenges of inference from -omics data. In the empirical analyses (n = 703), we evaluated the time-dependent relationship between childhood abuse and genomewide DNAm. In simulations, selective inference and the max-|t|-test performed best: Both controlled the familywise error rate and yielded moderate statistical power. Empirical analyses using SLCMA revealed time-dependent effects of childhood abuse on DNAm. Our findings show that SLCMA, applied and interpreted appropriately, can be used in high-throughput settings to examine time-dependent effects underlying exposure-outcome relationships over the life course. We provide recommendations for applying the SLCMA in -omics settings and encourage researchers to move beyond analyses of exposed versus unexposed individuals.

Pre-pregnancy maternal BMI classification is associated with preschool childhood diet quality and childhood obesity in the Avon Longitudinal Study of Parents and Children

OBJECTIVE

To explore the effect of maternal BMI class pre-pregnancy (overweight/obese v. healthy weight/underweight) on childhood diet quality and on childhood overweight/obesity risk.

DESIGN

Dietary data were collected using 3-d parental-completed food records for their children at ages 18 and 43 months. An index of diet quality was derived by classification of food items into core and non-core foods. Adjusted multiple linear regression analyses were used to explore the effect of maternal BMI class on diet quality in their children.

SETTING

Avon, UK.

PARTICIPANTS

A 10% subsample of the Avon Longitudinal Study of Parents and Children. Nine-hundred and eighty children provided complete dietary data at 18 months and 769 at 43 months.

RESULTS

Children with overweight/obese mothers consumed greater amounts of energy from non-core foods than children with healthy weight/underweight mothers (0·20 MJ (48 kcal)/d more at 18 months (P < 0·001); 0·19 MJ (45 kcal)/d more at 43 months (P = 0·008)) in adjusted models. Diet quality deteriorated between 18 and 43 months (children reduced their dietary energy intake from core foods (P < 0·001) and increased intake from non-core foods (P < 0·001)). However, this change was not associated with maternal BMI class in adjusted models. Having an overweight/obese mother was associated with an increased odds of the child being overweight/obese at 43 months (OR 1·74 (1·17, 2·58)).

CONCLUSIONS

Children aged 18 and 43 months with overweight/obese mothers are likely to have a poorer quality diet than those with healthy/underweight mothers. Parents should be supported in discouraging the consumption of non-core foods in children at these ages.

Investigating attention-deficit hyperactivity disorder and autism spectrum disorder traits in the general population: What happens in adult life?

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are generally considered early-onset disorders so most research has therefore tended to focus on children. Differences between ADHD/ASD in adult life and childhood have been noted, but few population-based studies have examined them in adulthood. Furthermore, the interpretation of findings is hampered by changes in measure and from parent report to self-report.

METHOD

We examined continuous/trait measures of parent- and self-rated ADHD and ASD in adulthood (age 25 years) in a UK prospective longitudinal sample ALPSAC (the Avon Longitudinal Study of Parents and Children), using many of the same measures that parents reported on in childhood (N = 6,064). Our aim was to investigate these traits in this population for mean-level sex differences, overlaps with other cognitive, learning and communication problems and their associations with polygenic risk scores (PRS) for neuropsychiatric disorders (ADHD, ASD, schizophrenia, depression and anxiety).

RESULTS

ADHD and ASD traits in adulthood, as in childhood, showed associations with childhood cognitive, learning and communication problems and adult communication/language measures, although less so for self-ratings than parent-ratings. Males had higher ADHD and ASD trait levels, but this was not as marked as in childhood. In adulthood, ADHD (both parent- and self-rated) and ASD (parent-rated) symptoms showed associations with ADHD PRS; self-reported ADHD also showed association with depression PRS, whereas self-reported ASD did not show strong PRS associations.

CONCLUSIONS

Our findings suggest that in young adults, ADHD and ASD symptoms have similar characteristics as they do in childhood. Associations with other cognitive, learning and communication problems, and ADHD PRS were somewhat less pronounced for self-reported adult ADHD and ASD symptoms, suggesting that even at age 25, parent reports, where available, could be clinically useful.

Prenatal and Childhood Tobacco Smoke Exposure Are Associated With Sleep-Disordered Breathing Throughout Early Childhood

OBJECTIVE

To determine whether prenatal and childhood tobacco smoke exposure (TSE) are each independently associated with mild sleep-disordered breathing (SDB) symptoms throughout early childhood, and whether the association between childhood TSE and SDB differs according to the level of prenatal exposure.

METHODS

Longitudinal cohort study, using data from the Avon Longitudinal Study of Parents and Children, a population-based birth cohort from the United Kingdom. Primary exposures were repeated measures of mother-reported prenatal and childhood TSE through age 7 years. Outcomes were mother-reported measures of mild SDB symptoms, including snoring, mouth breathing, and witnessed apnea, repeated annually through age 7 years.

RESULTS

A total of 12,030 children were followed for a median duration of 7 years. About 24.2% were exposed to prenatal tobacco smoke, 46.2% were exposed at least once in childhood, and 20.6% were exposed during both periods. Both prenatal and childhood TSE were associated with SDB symptoms throughout early childhood (adjusted OR [aOR] for any prenatal TSE 1.23; 95% confidence interval [CI] 1.08, 1.40; aOR for any childhood TSE 1.17; 95% CI 1.06, 1.29). We observed a dose-response effect between TSE and SBD symptoms, and found evidence of effect modification for those exposed during both time periods (combined high level exposure both prenatally and during childhood: aOR snoring 2.43 [95% CI 1.50, 3.93], aOR apnea 2.65 [95% CI 1.46, 4.82]).

CONCLUSIONS

Prenatal and childhood TSE were both independently associated with mild SDB symptoms throughout early childhood in a dose-dependent manner, further supporting the critical importance of maintaining a tobacco-free environment throughout gestation and childhood.

Child and adolescent mental health trajectories in relation to exclusion from school from the Avon Longitudinal Study of Parents and Children

BACKGROUND

As the prevalence of childhood mental health conditions varies by age and gender, we explored whether there were similar variations in the relationship between psychopathology and exclusion from school in a prospective UK population-based birth cohort.

METHOD

The Avon Longitudinal Study of Parents and Children collected reports of exclusion at 8 years and 16 years. Mental health was assessed at repeated time points using the Strengths and Difficulties Questionnaire (SDQ).

RESULTS

Using adjusted linear mixed effects models, we detected a nonlinear interaction between exclusion and age related to poor mental health for boys [adjusted coefficient 1.13 (95% confidence interval 0.55-1.71)] excluded by age 8, but not for girls. The SDQ scores of boys who were excluded in primary school were higher than their peers from age 3, and increasingly diverged over time. As teenagers, these interactions appeared for both genders [boys' adjusted coefficient 0.18 (0.10-0.27); girls 0.29 (0.17-0.40)]. For teenage girls, exclusion by 16 was followed by deteriorating mental health. Family adversity predicted exclusion in all analyses.

CONCLUSION

Prompt access to effective intervention for children in poor mental health may improve both mental health and access to education.

KEY PRACTITIONER MESSAGE

Children who were subsequently excluded from school often faced family adversity and had poor mental health, which suggests the need for an interdisciplinary response and a multiagency approach. Poor mental health may contribute to and result from exclusion from school, so both mental health and education practitioners have a key role to play. Boys who enter school with poor mental health are at high risk of exclusion in primary school, which prompt assessment and intervention may prevent. Both boys and girls who are excluded between the ages of 15 and 16 years may have poor, and in the case of girls, deteriorating, mental health.

Maths attitudes, school affect and teacher characteristics as predictors of maths attainment trajectories in primary and secondary education

Maths attainment is essential for a wide range of outcomes relating to further education, careers, health and the wider economy. Research suggests a significant proportion of adults and adolescents are underachieving in maths within the UK, making this a key area for research. This study investigates the role of children's perceptions of the school climate (children's affect towards school and student-teacher relationships), their attitudes towards maths and teacher characteristics as predictors of maths attainment trajectories, taking the transition from primary to secondary education into consideration. Two growth models were fit using secondary data analysis of the Avon Longitudinal Study of Parents and Children (ALSPAC). The first model, which looked at predictors of maths attainment in primary education, found significant associations only between positive maths attitudes and increased maths attainment. The second model, which looked at predictors of maths attainment in secondary education, found significant associations between increased maths attainment and positive maths attitudes, decreased school belonging, positive student-teacher relationships and increased teacher fairness. The findings suggest that the secondary education school environment is particularly important for maths attainment.

Predictors of mathematical attainment trajectories across the primary-to-secondary education transition: parental factors and the home environment

A 'maths crisis' has been identified in the UK, with many adults and adolescents underachieving in maths and numeracy. This poor performance is likely to develop from deficits in maths already present in childhood. Potential predictors of maths attainment trajectories throughout childhood and adolescence relate to the home environment and aspects of parenting including parent-child relationships, parental mental health, school involvement, home teaching, parental education and gendered play at home. This study examined the aforementioned factors as predictors of children's maths attainment trajectories (age 7-16) across the challenging transition to secondary education. A secondary longitudinal analysis of the Avon Longitudinal Study of Parents and Children found support for parental education qualifications, a harmonious parent-child relationship and school involvement at age 11 as substantial predictors of maths attainment trajectories across the transition to secondary education. These findings highlight the importance of parental involvement for maths attainment throughout primary and secondary education.

Externalising pathways to alcohol-related problems in emerging adulthood

BACKGROUND

Both 'early-onset persistent' and 'adolescent-onset' conduct problems (CPs) are associated with alcohol-related problems in emerging adulthood. The escalation of early CPs into criminal behaviour and heavy alcohol consumption prior to emerging adulthood are both likely to be important pathways.

METHODS

Data were analysed from 3,038 young people in a UK birth cohort, the Avon Longitudinal Study of Parents and Children. The exposure was developmental trajectories of CPs ('low', 'childhood-limited', 'adolescent-onset' and 'early-onset persistent') between ages 4 and 13 years. The mediator was latent classes representing heavy alcohol consumption and/ or criminal behaviour at age 15 years. For the outcome, a quadratic latent growth curve was estimated to capture nonlinear change in alcohol-related problems between ages 18 and 23 years.

RESULTS

Those with 'early-onset persistent' [b(95% CI) = 1.16 (0.17, 2.14)] and 'adolescent-onset' CPs [b(95% CI) = 1.31 (0.17, 2.45)] had higher levels of alcohol-related problems at age 18 years compared to those with 'low' CPs', but there was little evidence of an association with alcohol-related problems after age 19 years. There was evidence for an indirect effect of 'early-onset persistent' CPs [b(95% CI) = 1.12 (0.52, 1.72)] on alcohol-related problems at age 18 years via the latent classes of alcohol and criminal behaviour in adolescence. This was not found for 'adolescent-onset' CPs [b(95% CI) = 0.35 (-0.36, 1.07)].

CONCLUSIONS

Strong associations exist between early CPs, adolescent alcohol consumption and criminal behaviour and alcohol-related problems at age 18 years. Associations between early CPs and alcohol-related problems weakened considerably across emerging adulthood.

Association of Prenatal Alcohol Exposure and Offspring Depression: A Negative Control Analysis of Maternal and Partner Consumption

BACKGROUND

Previous research has suggested that intrauterine alcohol exposure is associated with a variety of adverse outcomes in offspring. However, few studies have investigated its association with offspring internalizing disorders in late adolescence.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we investigated the associations of maternal drinking in pregnancy with offspring depression at age 18 and 24 (n = 13,480). We also examined partner drinking as a negative control for intrauterine exposure for comparison.

RESULTS

Offspring of mothers that consumed any alcohol at 18 weeks gestation were at increased risk of having a diagnosis of depression (fully adjusted model: OR 1.17, 95% CI 1.02 to 1.34), but there was no clear evidence of association between partners' alcohol consumption at 18 weeks gestation during pregnancy and increased risk of offspring depression (fully adjusted model: OR 0.87, 95% CI 0.74 to 1.01). Postestimation tests found a positive difference between the association of maternal and partner alcohol use on offspring depression, showing a stronger association for maternal compared with partner alcohol use (OR 1.41, CI 1.07 to 1.84).

CONCLUSIONS

Maternal drinking in pregnancy was associated with increased risk of offspring depression at age 18. Residual confounding may explain this association, but the negative control comparison of paternal drinking provides some evidence that it may be causal, and this warrants further investigation.

Associations between infant and toddler regulatory problems, childhood co-developing internalising and externalising trajectories, and adolescent depression, psychotic and borderline personality disorder symptoms

BACKGROUND

Early regulatory problems (RPs) are associated with childhood internalising and externalising symptoms. Internalising and externalising symptoms, in turn, are associated with adolescent psychopathology (e.g. personality disorders, depression). We examined whether RPs are directly associated with adolescent psychopathology, or whether associations are indirect via childhood internalising and externalising symptoms.

METHODS

We used data from the Avon Longitudinal Study of Parents and Children. Mothers reported on their child's RPs at 6, 15-18 and 24-30 months, and internalising and externalising symptoms at 4, 7, 8 and 9.5 years. Adolescent psychotic, depression and BPD symptoms were assessed at 11-12 years. Children were grouped by their patterns of co-developing internalising and externalising symptoms using parallel process latent class growth analysis (PP-LCGA). Path analysis was used to examine direct and indirect associations from RPs to the three adolescent outcomes.

RESULTS

There were four groups of children with distinct patterns of co-developing internalising and externalising (INT/EXT) symptoms. Most children (53%) demonstrated low-moderate and stable levels of INT/EXT symptoms. A small proportion (7.7%) evidenced moderate and increasing INT and high stable EXT symptoms: this pattern was strongly predictive of adolescent psychopathology (e.g. depression at 11 years: unadjusted odds ratio = 5.62; 95% confidence intervals = 3.82, 8.27). The other two groups were differentially associated with adolescent outcomes (i.e. moderate-high increasing INT/moderate decreasing EXT predicted mother-reported depression at 12, while low stable INT/moderate-high stable EXT predicted child-reported depression at 11). In path analysis, RPs at each time-point were significantly indirectly associated with symptoms of BPD and child- and mother-reported depression symptoms via the most severe class of INT/EXT symptoms.

CONCLUSIONS

Consistent with a cascade model of development, RPs are predictive of higher levels of co-developing INT/EXT symptoms, which in turn increase risk of adolescent psychopathology. Clinicians should be aware of, and treat, early RPs to prevent chronic psychopathology.

General psychopathology, internalising and externalising in children and functional outcomes in late adolescence

BACKGROUND

Internalising and externalising problems commonly co-occur in childhood. Yet, few developmental models describing the structure of child psychopathology appropriately account for this comorbidity. We evaluate a model of childhood psychopathology that separates the unique and shared contribution of individual psychological symptoms into specific internalising, externalising and general psychopathology factors and assess how these general and specific factors predict long-term outcomes concerning criminal behaviour, academic achievement and affective symptoms in three independent cohorts.

METHODS

Data were drawn from independent birth cohorts (Avon Longitudinal Study of Parents and Children (ALSPAC), N = 11,612; Generation R, N = 7,946; Maternal Adversity, Vulnerability and Neurodevelopment (MAVAN), N = 408). Child psychopathology was assessed between 4 and 8 years using a range of diagnostic and questionnaire-based measures, and multiple informants. First, structural equation models were used to assess the fit of hypothesised models of shared and unique components of psychopathology in all cohorts. Once the model was chosen, linear/logistic regressions were used to investigate whether these factors were associated with important outcomes such as criminal behaviour, academic achievement and well-being from late adolescence/early adulthood.

RESULTS

The model that included specific factors for internalising/externalising and a general psychopathology factor capturing variance shared between symptoms regardless of their classification fits well for all of the cohorts. As hypothesised, general psychopathology factor scores were predictive of all outcomes of later functioning, while specific internalising factor scores predicted later internalising outcomes. Specific externalising factor scores, capturing variance not shared by any other psychological symptoms, were not predictive of later outcomes.

CONCLUSIONS

Early symptoms of psychopathology carry information that is syndrome-specific as well as indicative of general vulnerability and the informant reporting on the child. The 'general psychopathology factor' might be more relevant for long-term outcomes than specific symptoms. These findings emphasise the importance of considering the co-occurrence of common internalising and externalising problems in childhood when considering long-term impact.

Methods for Dealing With Missing Covariate Data in Epigenome-Wide Association Studies

Multiple imputation (MI) is a well-established method for dealing with missing data. MI is computationally intensive when imputing missing covariates with high-dimensional outcome data (e.g., DNA methylation data in epigenome-wide association studies (EWAS)), because every outcome variable must be included in the imputation model to avoid biasing associations towards the null. Instead, EWAS analyses are reduced to only complete cases, limiting statistical power and potentially causing bias. We used simulations to compare 5 MI methods for high-dimensional data under 2 missingness mechanisms. All imputation methods had increased power over complete-case (C-C) analyses. Imputing missing values separately for each variable was computationally inefficient, but dividing sites at random into evenly sized bins improved efficiency and gave low bias. Methods imputing solely using subsets of sites identified by the C-C analysis suffered from bias towards the null. However, if these subsets were added into random bins of sites, this bias was reduced. The optimal methods were applied to an EWAS with missingness in covariates. All methods identified additional sites over the C-C analysis, and many of these sites had been replicated in other studies. These methods are also applicable to other high-dimensional data sets, including the rapidly expanding area of "-omics" studies.

Differential associations of allergic disease genetic variants with developmental profiles of eczema, wheeze and rhinitis

BACKGROUND

Allergic diseases (eczema, wheeze and rhinitis) in children often present as heterogeneous phenotypes. Understanding genetic associations of specific patterns of symptoms might facilitate understanding of the underlying biological mechanisms.

OBJECTIVE

To examine associations between allergic disease-related variants identified in a recent genome-wide association study and latent classes of allergic diseases (LCADs) in two population-based birth cohorts.

METHODS

Eight previously defined LCADs between birth and 11 years: "No disease," "Atopic march," "Persistent eczema and wheeze," "Persistent eczema with later-onset rhinitis," "Persistent wheeze with later-onset rhinitis," "Transient wheeze," "Eczema only" and "Rhinitis only" were used as the study outcome. Weighted multinomial logistic regression was used to estimate associations between 135 SNPs (and a polygenic risk score, PRS) and LCADs among 6345 individuals from The Avon Longitudinal Study of Parents and Children (ALSPAC). Heterogeneity across LCADs was assessed before and after Bonferroni correction. Results were replicated in Manchester Asthma and Allergy Study (MAAS) (n = 896) and pooled in a meta-analysis.

RESULTS

We found strong evidence for differential genetic associations across the LCADs; pooled PRS heterogeneity P-value = 3.3 × 10-14 , excluding "no disease" class. The associations between the PRS and LCADs in MAAS were remarkably similar to ALSPAC. Two SNPs (a protein-truncating variant in FLG and a SNP within an intron of GSDMB) had evidence for differential association (pooled P-values ≤ 0.006). The FLG locus was differentially associated across LCADs that included eczema, with stronger associations for LCADs with comorbid wheeze and rhinitis. The GSDMB locus in contrast was equally associated across LCADs that included wheeze.

CONCLUSIONS AND CLINICAL RELEVANCE

We have shown complex, but distinct patterns of genetic associations with LCADs, suggesting that heterogeneous mechanisms underlie individual disease trajectories. Establishing the combination of allergic diseases with which each genetic variant is associated may inform therapeutic development and/or predictive modelling.

Changes in oral health behaviours between childhood and adolescence: Findings from a UK cohort study

OBJECTIVE

Oral health is an important part of general health and well-being. Health behaviours may change throughout a person's life, but the stage from childhood to adolescence is critical because influences from peers increase while those from parents and other family members decrease. The objective of this study was to identify changes in oral health behaviours between childhood and adolescence, and investigate whether changes differed by sex.

METHODS

This study used data on 1860 participants from the Avon Longitudinal Study of Parents and Children (ALSPAC) who completed dental questionnaires at ages 7.5, 10.5 and 17.5 years. Associations between age and oral health behaviours were assessed using random effects logistic regression models. Males and females were analysed together or separately, depending on evidence for sex-age interactions.

RESULTS

At age 7.5, 83% brushed their teeth frequently, 98% visited the dentist frequently and 90% drank fizzy drinks. The percentage who brushed their teeth at least twice a day decreased with age for males (odds ratio 0.96 [95% confidence interval 0.94, 0.99] per year of age) and increased with age for females (1.03 [1.01, 1.06]). Electric toothbrush usage decreased with age, with a slightly larger decrease in females (0.82 [0.80, 0.85]) than in males (0.87 [0.84, 0.90]). The percentage visiting the dentist at least once a year decreased with age (0.77 [0.73, 0.81]); the decrease was greatest between the older ages. Fizzy drink and juice consumption increased with age (1.38 [1.23, 1.57] and 1.33 [1.24, 1.44] respectively), whereas there was no change in water consumption (1.00 [0.91, 1.09]); these data were available only for the younger two ages.

CONCLUSIONS

Unfavourable changes in oral health behaviours, some of which were sex-specific, have been demonstrated in this cohort. Hence, childhood to adulthood may be an important intervening time to prevent early deterioration of oral health.

Pathways between early-life adversity and adolescent self-harm: the mediating role of inflammation in the Avon Longitudinal Study of Parents and Children

BACKGROUND

Adverse childhood experiences (ACEs) such as physical and emotional abuse are strongly associated with self-harm, but mechanisms underlying this relationship are unclear. Inflammation has been linked to both the experience of ACEs and self-harm or suicide in prior research. This is the first study to examine whether inflammatory markers mediate the association between exposure to ACEs and self-harm.

METHODS

Participants were 4,308 young people from the Avon Longitudinal Study of Parents and Children (ALSPAC), a population-based birth cohort in the United Kingdom. A structural equation modelling approach was used to fit a mediation model with the number of ACEs experienced between ages 0 and 9 years old (yo), levels of the inflammatory markers interleukin-6 and C-reactive protein measured at 9.5 yo, and self-harm reported at 16 yo.

RESULTS

The mean number of ACEs young people experienced was 1.41 (SE 0.03). Higher ACE scores were associated with an increased risk of self-harm at 16 yo (direct effect relative risk (RR) per additional ACE 1.11, 95% CI 1.05, 1.18, p < 0.001). We did not find evidence of an indirect effect of ACEs on self-harm via inflammation (RR 1.00, 95% CI 1.00, 1.01, p = 0.38).

CONCLUSIONS

Young people who have been exposed to ACEs are a group at high risk of self-harm. The association between ACEs and self-harm does not appear to be mediated by an inflammatory process in childhood, as indexed by peripheral levels of circulating inflammatory markers measured in childhood. Further research is needed to identify alternative psychological and biological mechanisms underlying this relationship.

Relative effects of breastfeeding intention and practice on maternal responsiveness

Our objective was to examine the differential effects of antenatal breastfeeding intention (BI) and breastfeeding practice (BP) on maternal postnatal responsiveness. We conducted a secondary analysis of longitudinal data from a subsample of 962 mother-infant dyads from a U.K.-based birth cohort study the Avon Longitudinal Study of Parents and Children. Exposures were BI and BPs measured at 32 weeks of gestation and 18 months' postpartum. The outcome was maternal responsiveness assessed at 12 months' postpartum. We used logistic regression analyses unadjusted and adjusted for confounders. Intention to breastfeed was associated with increased odds of postnatal maternal responsiveness independent of BP, adjusted odds ratio (OR) = 2.34, 95% CI [1.42, 3.86]. There was no evidence that BP was an independent predictor of maternal responsiveness, OR = 0.93, 95% CI [0.55, 1.57]. Life-course epidemiology analyses demonstrated that maternal responsiveness is most positive when both BI and BP are present. This is the first population-based study to provide evidence that BI during pregnancy is more strongly associated with maternal postnatal responsiveness than is BP. Further research is needed to understand the determinants of BI in pregnancy and its relationships with maternal responsiveness.

Cross-cohort change in adolescent outcomes for children with mental health problems

BACKGROUND

Child mental health problems are common. Previous studies have examined secular changes in their prevalence but have not assessed whether later outcomes have changed. We therefore aimed to test whether outcomes of child mental health problems have changed over a 40-year period.

METHODS

Three cohorts were utilized: The National Child Development Study (NCDS: N = 14,544, aged 7 in 1965), the Avon Longitudinal Study of Parents and Children (ALSPAC: N = 8,188, aged 7 in 1998), and the Millennium Cohort Study (MCS: N = 13,192, aged 7 in 2008). Mental health problems at age 7 were identified using the parent-reported Rutter-A scale (NCDS) and Strengths and Difficulties Questionnaire (ALSPAC and MCS). Associated outcomes were compared across cohorts: age 11 social functioning, age 16 exam attainment and age 16 mental health.

RESULTS

Child mental health problems were common in each cohort (boys: 7.0%-9.7%; girls: 5.4%-8.4%). Child mental health problems became more strongly associated with social functioning problems (boys: NCDS OR = 1.95 (1.50, 2.53), MCS OR = 3.77 (2.89, 4.92); interaction p < .001; girls: NCDS OR = 1.69 (1.22, 2.33), MCS OR = 3.99 (3.04, 5.25), interaction p < .001), lower academic attainment for boys (NCDS OR = 0.49 (0.31, 0.78), ALSPAC OR = 0.30 (0.22, 0.41), interaction p = .009), and age 16 mental health problems (boys: NCDS d' = 0.55 (0.38, 0.72), ALSPAC d' = 0.95 (0.73, 1.16); interaction p = .004; girls: NCDS d' = 0.50 (0.34, 0.65), ALSPAC d' = 0.99 (0.78, 1.20); interaction p < .001).

CONCLUSIONS

Child mental health problems have become more strongly associated with negative social, educational and mental health outcomes in recent generations.

Causes of variability in latent phenotypes of childhood wheeze

BACKGROUND

Latent class analysis (LCA) has been used extensively to identify (latent) phenotypes of childhood wheezing. However, the number and trajectory of discovered phenotypes differed substantially between studies.

OBJECTIVE

We sought to investigate sources of variability affecting the classification of phenotypes, identify key time points for data collection to understand wheeze heterogeneity, and ascertain the association of childhood wheeze phenotypes with asthma and lung function in adulthood.

METHODS

We used LCA to derive wheeze phenotypes among 3167 participants in the ALSPAC cohort who had complete information on current wheeze recorded at 14 time points from birth to age 16½ years. We examined the effects of sample size and data collection age and intervals on the results and identified time points. We examined the associations of derived phenotypes with asthma and lung function at age 23 to 24 years.

RESULTS

A relatively large sample size (>2000) underestimated the number of phenotypes under some conditions (eg, number of time points <11). Increasing the number of data points resulted in an increase in the optimal number of phenotypes, but an identical number of randomly selected follow-up points led to different solutions. A variable selection algorithm identified 8 informative time points (months 18, 42, 57, 81, 91, 140, 157, and 166). The proportion of asthmatic patients at age 23 to 24 years differed between phenotypes, whereas lung function was lower among persistent wheezers.

CONCLUSIONS

Sample size, frequency, and timing of data collection have a major influence on the number and type of wheeze phenotypes identified by using LCA in longitudinal data.

Parents' postnatal depressive symptoms and their children's academic attainment at 16 years: Pathways of risk transmission

The aim of the study was to examine whether parents' increased postnatal depressive symptoms predicted children's academic attainment over time and whether the parent-child relationship, children's prior academic attainment, and mental health mediated this association. We conducted secondary analyses on the Avon Longitudinal Study of Parents and Children data (12,607 mothers, 9,456 fathers). Each parent completed the Edinburgh-Postnatal Depression Scale at 8 weeks after the child's birth (predictor) and a questionnaire about the mother-child and father-child relationship at 7 years and 1 month (mediator). The children's mental health problems were assessed with the teacher version of the Strengths and Difficulties Questionnaire at 10-11 years (mediator). We used data on the children's academic attainment on UK Key Stage 1 (5-7 years; mediator) and Key Stage 4 (General Certificate of Secondary Education 16 years) (outcome). We adjusted for the parents' education, and child gender and cognitive ability. The results revealed that parents' depressive symptoms at 8 weeks predicted lower academic performance in children at 16 years. Mothers' postnatal depressive symptoms had an indirect effect through children's mental health problems on academic outcomes at 16 years via negative mother-child relationship, and prior academic attainment. There was a significant negative indirect effect of fathers' postnatal depressive symptoms on academic attainment at 16 years via negative father-child relationship on child mental health. The findings suggest that the family environment (parental mental health and parent-child relationship) and children's mental health should be potential targets for support programmes for children of depressed parents.

Association of Height Growth in Puberty with Lung Function. A Longitudinal Study

Rationale: Puberty may influence lung function, but the precise role of pubertal height growth in lung development is unclear.Objectives: To examine associations of timing of puberty and peak velocity of pubertal height growth with lung function in adolescence and early adulthood.Methods: Longitudinal analyses of repeat height measurements from age 5 to 20 years for a British birth cohort with 4,772 males and 4,849 females were conducted to characterize height growth trajectories and to derive pubertal age and peak height velocity using the validated SITAR (SuperImposition by Translation and Rotation) model. Association of these estimates with prebronchodilator and post-bronchodilator spirometry measures: FEV1; FVC; FEV1/FVC; FEF25-75% at age 15 and 24 years were investigated using multivariable regression models adjusted for lung function at age 8 years, height and age at time of outcome measurements, and potential confounders.Measurements and Main Results: Later pubertal age and greater peak velocity were associated with higher FEV1 and FVC at 24 years in both sexes. A 1-year increase in pubertal age was associated with a 263-ml higher FVC (95% confidence interval [CI], 167-360 ml) for males (n = 567) and 100-ml (95% CI, 50-150 ml) higher FVC for females (n = 990). A 1-cm/yr increase in peak velocity was associated with 145-ml (95% CI, 56-234 ml) and 50-ml (95% CI, 2-99 ml) increases in FVC for males and females, respectively. No associations were found with FEV1/FVC.Conclusions: Later onset and greater peak velocity of height growth in puberty are associated with increased FEV1 and FVC in young adults but there was no evidence of dysanapsis of pubertal lung growth.

Moderating effect of mode of delivery on the genetics of intelligence: Explorative genome-wide analyses in ALSPAC

INTRODUCTION

Intelligence is a core construct of individual differences in cognitive abilities and a strong predictor of important life outcomes. Within recent years, rates of cesarean section have substantially increased globally, though little is known about its effect on neurodevelopmental trajectories. Thus, we aimed to investigate the influence of delivery by cesarean section on the genetics of intelligence in children.

METHODS

Participants were recruited through the Avon Longitudinal Study of Parents and Children (ALSPAC). Intelligence was measured by the Wechsler Intelligence Scale for Children (WISC). Genotyping was performed using the Illumina Human Hap 550 quad genome-wide SNP genotyping platform and was followed by imputation using MACH software. Genome-wide interaction analyses were conducted using linear regression.

RESULTS

A total of 2,421 children and 2,141,747 SNPs were subjected to the genome-wide interaction analyses. No variant reached genome-wide significance. The strongest interaction was observed at rs17800861 in the GRIN2A gene (β = -3.43, 95% CI = -4.74 to -2.12, p = 2.98E-07). This variant is predicted to be located within active chromatin compartments in the hippocampus and may influence binding of the NF-kappaB transcription factor.

CONCLUSIONS

Our results may indicate that mode of delivery might have a moderating effect on genetic disposition of intelligence in children. Studies of considerable sizes (>10,000) are likely required to more robustly detect variants governing such interaction. In summary, the presented findings prompt the need for further studies aimed at increasing our understanding of effects various modes of delivery may have on health outcomes in children.

Meta-Analysis of Genetic Influences on Initial Alcohol Sensitivity

BACKGROUND

Previous studies indicate that low initial sensitivity to alcohol may be a risk factor for later alcohol misuse. Evidence suggests that initial sensitivity is influenced by genetic factors, but few molecular genetic studies have been reported.

METHODS

We conducted a meta-analysis of 2 population-based genome-wide association studies of the Self-Rating of the Effects of Alcohol scale. Our final sample consisted of 7,339 individuals (82.3% of European descent; 59.2% female) who reported having used alcohol at least 5 times. In addition, we estimated single nucleotide polymorphism (SNP)-based heritability and conducted a series of secondary aggregate genetic analyses.

RESULTS

No individual locus reached genome-wide significance. Gene and set based analyses, both overall and using tissue-specific expression data, yielded largely null results, and genes previously implicated in alcohol problems and consumption were overall not associated with initial sensitivity. Only 1 gene set, related to hormone signaling and including core clock genes, survived correction for multiple testing. A meta-analysis of SNP-based heritability resulted in a modest estimate of h SNP 2  = 0.19 (SE = 0.10), though this was driven by 1 sample (N = 3,683, h SNP 2  = 0.36, SE = 0.14, p = 0.04). No significant genetic correlations with other relevant outcomes were observed.

CONCLUSIONS

Findings yielded only modest support for a genetic component underlying initial alcohol sensitivity. Results suggest that its biological underpinnings may diverge somewhat from that of other alcohol outcomes and may be related to core clock genes or other aspects of hormone signaling. Larger samples, ideally of prospectively assessed samples, are likely necessary to improve gene identification efforts and confirm the current findings.

Investigating late-onset ADHD: a population cohort investigation

BACKGROUND

Adult ADHD has been assumed to be a continuation of childhood-onset ADHD. However, recent studies have identified individuals with ADHD in adulthood who have not had ADHD in childhood. Whether or not these individuals have a 'typical' neurodevelopmental profile is not clear.

METHODS

We tested two explanations for the emergence of apparent late-onset ADHD symptomatology using the ALSPAC epidemiological cohort, by grouping individuals according to their scores on the Strengths and Difficulties Questionnaire (SDQ) hyperactivity subscale at ages 12 and 17 years. First, we tested whether some of those with apparent late-onset ADHD symptoms had been potentially misclassified on the basis of earlier SDQ hyperactivity scores (ages 7, 8 and 9 years) or of subthreshold symptoms at age 12 years. Second, we investigated the possibility that those with 'genuine' late-onset ADHD symptoms had a delayed manifestation of the same liability that underlies childhood-onset symptoms, by investigating whether they had a similar profile of neurodevelopmental impairments (in the domains of autistic symptomatology, language, reading, spelling, executive functioning and IQ) as those with typical childhood-onset ADHD.

RESULTS

N = 56/75 (75%) of those with apparent late-onset ADHD had had high ADHD scores at least one point in childhood, suggesting that they may have been misclassified on the basis of their score at age 12 years. The remaining 19 individuals (25%) with genuine late-onset ADHD symptoms did not show a profile of neurodevelopmental impairment typically seen in ADHD, instead showing similar levels of autistic symptoms, language skills, executive functioning ability and IQ to those without ADHD symptoms. The only exceptions were that this group showed reading and spelling problems at age 9 years.

CONCLUSIONS

Our work suggests that this small number of individuals with genuine late-onset symptoms may not be most appropriately considered as having a typical neurodevelopmental disorder.

Do Maternal Dietary Antioxidants Modify the Relationship Between Binge Drinking and Small for Gestational Age? Findings from a Longitudinal Cohort Study

BACKGROUND

Vitamin C, vitamin E, and carotenoids are potent dietary antioxidants that have been shown to attenuate ethanol-induced harm in animal models of fetal alcohol spectrum disorders. A diet low in antioxidant-rich foods may induce a state of oxidative stress in the context of maternal alcohol consumption during pregnancy, potentially causing growth restriction in the developing fetus.

METHODS

We conducted a secondary analysis of a longitudinal U.K. birth cohort. The sample comprised 9,699 women and their babies in Avon, U.K., with an estimated delivery date between April 1, 1991 and December 31, 1992. Alcohol consumption data were self-reported at 18 weeks' gestation via a postal questionnaire. Women reported any binge drinking (≥4 U.K. units/occasion) during the past month. Dietary data were self-reported at 32 weeks' gestation using a food frequency questionnaire. Estimated intakes of vitamins C and E and carotenoids were categorized into quartiles. Logistic regression models with interaction terms were used to investigate relationships between maternal binge drinking, dietary antioxidants, and fetal growth. Models were adjusted for maternal sociodemographic and lifestyle characteristics. Small for gestational age (SGA; <10th percentile) was defined using customized birth centiles.

RESULTS

In the unadjusted models, binge drinking was associated with higher risk of SGA birth (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.10, 1.72, p = 0.005), and higher maternal intakes of vitamin C (OR = 0.90, 95% CI 0.84, 0.96, p = 0.002) and vitamin E (OR = 0.90, 95% CI 0.84, 0.95, p < 0.0001) were associated with lower risk of SGA birth. However, addition of potentially confounding variables attenuated these relationships. Likelihood ratio tests indicated that interaction terms were not significant for vitamin C (p = 0.116), vitamin E (p = 0.059), or carotenoid intakes (p = 0.174).

CONCLUSIONS

There was no evidence of maternal intake of dietary antioxidants modifying the relationship between maternal binge drinking and SGA birth.

Implication of the APP Gene in Intellectual Abilities

Background:

Cognitive functions are highly heritable and polygenic, though the source of this genetic influence is unclear. On the neurobiological level, these functions rely on effective neuroplasticity, in which the activity-regulated cytoskeleton associated protein (ARC) plays an essential role.

Objectives:

To examine whether the ARC gene complex may contribute to the genetic components of intellectual function given the crucial role of ARC in brain plasticity and memory formation.

Methods:

The ARC complex was tested for association with intelligence (IQ) in children from the Avon Longitudinal Study of Parents and Children (ALSPAC, N = 5,165). As Alzheimer’s disease (AD) shares genetics with cognitive functioning, the association was followed up in an AD sample (17,008 cases, 37,154 controls).

Results:

The ARC complex revealed association with verbal and total IQ (empirical p = 0.027 and 0.041, respectively) in the ALSPAC. The strongest single variant signal (rs2830077; empirical p = 0.018), within the APP gene, was confirmed in the AD sample (p = 2.76E-03). Functional analyses of this variant showed its preferential binding to the transcription factor CP2.

Discussion:

This study implicates APP in childhood IQ. While follow-up studies are needed, this observation could help elucidate the etiology of disorders associated with cognitive dysfunction, such as AD.

Maternal fish consumption during pregnancy and smoking behavioural patterns

n-3 Highly unsaturated fatty acids (HUFA), are essential components of neuronal membranes and mediate a range of complex bioactive properties including gene expression, myelination, cell-signalling and dopaminergic function. Deficits in n-3 HUFA have been linked to increased risks for addictive disorders, thus we posited that lower fish consumption would be associated with greater risks for perinatal smoking among 9640 mothers enroled in the Avon Longitudinal Study of Parents and Children. We used univariable and multivariable regression models to examine relationships between self-reported prenatal dietary intakes of n-3 HUFA-rich foods (fish and shellfish) and maternal smoking; outcomes included cessation and the number of cigarettes smoked per d. Both before and during pregnancy, there was consistent evidence (P<0·001) of protective fish intake-smoking associations; relative to mothers reporting no fish consumption, those who reported some fish consumption (<340 g/week) and high fish consumption (340 g+/week) at 32 weeks of gestation showed lower likelihoods of smoking (adjusted P values <0·001). Respective OR for these relationships were 0·87 (95% CI 0·77, 0·97) and 0·73 (95% CI 0·61, 0·86). Although the prevalence of smoking diminished, from a high of 31·6% (pre-pregnancy) to a low of 18·7% (second trimester), the magnitude of fish intake-smoking associations remained stable following adjustment for confounders. These observations suggest that greater fish or n-3 HUFA consumption should be evaluated as an intervention to reduce or prevent smoking in randomised clinical trials.

Using Y-Chromosomal Haplogroups in Genetic Association Studies and Suggested Implications

Y-chromosomal (Y-DNA) haplogroups are more widely used in population genetics than in genetic epidemiology, although associations between Y-DNA haplogroups and several traits, including cardiometabolic traits, have been reported. In apparently homogeneous populations defined by principal component analyses, there is still Y-DNA haplogroup variation which will result from population history. Therefore, hidden stratification and/or differential phenotypic effects by Y-DNA haplogroups could exist. To test this, we hypothesised that stratifying individuals according to their Y-DNA haplogroups before testing for associations between autosomal single nucleotide polymorphisms (SNPs) and phenotypes will yield difference in association. For proof of concept, we derived Y-DNA haplogroups from 6537 males from two epidemiological cohorts, Avon Longitudinal Study of Parents and Children (ALSPAC) (n = 5080; 816 Y-DNA SNPs) and the 1958 Birth Cohort (n = 1457; 1849 Y-DNA SNPs), and studied the robust associations between 32 SNPs and body mass index (BMI), including SNPs in or near Fat Mass and Obesity-associated protein (FTO) which yield the strongest effects. Overall, no association was replicated in both cohorts when Y-DNA haplogroups were considered and this suggests that, for BMI at least, there is little evidence of differences in phenotype or SNP association by Y-DNA structure. Further studies using other traits, phenome-wide association studies (PheWAS), other haplogroups and/or autosomal SNPs are required to test the generalisability and utility of this approach.

Longitudinal epigenetic predictors of amygdala:hippocampus volume ratio

BACKGROUND

The ratio between amygdala:hippocampal (AH) volume has been associated with multiple psychiatric problems, including anxiety and aggression. Yet, little is known about its biological underpinnings. Here, we used a methylome-wide approach to test (a) whether DNA methylation in early life (birth, age 7) prospectively associates with total AH volume ratio in early adulthood, and (b) whether significant DNA methylation markers are influenced by prenatal risk factors.

METHODS

Analyses were based on a subsample (n = 109 males) from the Avon Longitudinal Study of Parents and Children, which included measures of prenatal risk, DNA methylation (Infinium Illumina 450k), T1-weighted brain scans and psychopathology in early adulthood (age 18-21). Amygdala and hippocampus measures were derived using Freesurfer 5.3.0. Methylation markers related to AH volume ratio across time were identified using longitudinal multilevel modeling.

RESULTS

Amygdala:hippocampal volume ratio correlated positively with age 18 psychosis-like symptoms (p = .007). Methylation of a probe in the gene SP6 associated longitudinally with (a) higher AH volume ratio (FDR q-value = .01) and (b) higher stressful life events during pregnancy (p = .046). SP6 is expressed in the hippocampus and amygdala and has been implicated in cognitive decline in Alzheimer's disease. The association between SP6 DNA methylation, AH volume ratio and psychopathology was replicated in an independent dataset of 101 patients with schizophrenia and 111 healthy controls.

CONCLUSIONS

Our findings suggest that epigenetic alterations in genes implicated in neurodevelopment may contribute to a brain-based biomarker of psychopathology.

Anxiety disorders, gender nonconformity, bullying and self-esteem in sexual minority adolescents: prospective birth cohort study

BACKGROUND

Sexual minority adolescents (i.e. youth not exclusively heterosexual) report more anxiety than heterosexual youth on symptom questionnaires but no research has used standardised diagnostic tools to investigate anxiety disorder risk. This study uses a UK birth cohort to investigate the risk of anxiety disorders in sexual minority and heterosexual youth using a computerised structured clinical interview and explores the influence of gender nonconformity, bullying and self-esteem.

METHODS

Participants were 4,564 adolescents (2,567 girls and 1,996 boys) from the Avon Longitudinal Study of Parents and Children (ALSPAC). Logistic regression analyses were performed to investigate the association between sexual orientation at 15.5 years and the presence of an anxiety disorder at 17.5 years. Covariates including maternal occupation, ethnicity, mother-reported childhood gender nonconformity at 30, 42 and 57 months, child-reported gender nonconformity at 8 years, child-reported bullying between 12 and 16 years and self-esteem at 17.5 years were added sequentially to regression models.

RESULTS

Sexual minority adolescents (i.e. those not exclusively heterosexual) had higher early childhood gender nonconformity (CGN), lower self-esteem and reported more bullying than adolescents identifying as 100% heterosexual. Minority sexual orientation at 15.5 years was associated with increased risk of an anxiety disorder at 17.5 years for girls (OR 2.55, CI 1.85-3.52) and boys (OR 2.48, CI 1.40-4.39). Adjusting for ethnicity, maternal occupation, mother-reported and child-reported CGN had minimal impact on this association. Adjusting for bullying between 12 and 16 years and self-esteem at 17.5 years reduced the strength of the associations, although the overall association remained significant for both sexes (girls OR 2.14 and boys OR 1.93).

CONCLUSIONS

Sexual minority youth are at increased risk of anxiety disorders relative to heterosexual youth at 17.5 years. Bullying between 12-16 years and lower self-esteem may contribute to this risk.

Effects of Excessive Alcohol Use on Antisocial Behavior Across Adolescence and Early Adulthood

OBJECTIVE

Antisocial behavior (ASB) decreases with age in most of the population; however, excessive alcohol use can inhibit the desistance process. This study investigated whether excessive early drinking might slow a young person's overall pattern of crime desistance compared with that of others ("between-person effects") and whether short-term increases in alcohol consumption might result in short-term increases in ASB ("within-person effects").

METHOD

Frequency of ASB and typical alcohol consumption were assessed repeatedly in young people 15 to 21 years old in a population-based birth cohort (Avon Longitudinal Study of Parents and Children). Longitudinal trajectories showed ASB decreasing and alcohol use increasing across adolescence, which stabilized in adulthood. The parallel growth model was re-parameterized to simultaneously estimate the person-specific (or "between-person") and time-specific (or "within-person") influences of alcohol on ASB.

RESULTS

Typical alcohol consumption by young people 15 years old was positively associated with ASB cross-sectionally and into young adulthood (i.e., there were between-person effects of initial levels of alcohol consumption on initial [b 1.64, standard error 0.21; p < .001] and final [b 0.53, standard error 0.14; p < .001] levels of ASB). Within-person effects also were identified in early adulthood (b 0.06, standard error 0.02; p = .001), showing that when a young person reported consuming more alcohol than normal across the past year, that person also reported engaging in higher than usual levels of ASB.

CONCLUSION

The results are consistent with between- and within-person effects of excessive alcohol use on ASB desistence. Future research should further investigate this relation by investigating pathways into excessive alcohol use and ASB in adolescence.

Association between maternal vitamin D status in pregnancy and neurodevelopmental outcomes in childhood: results from the Avon Longitudinal Study of Parents and Children (ALSPAC)

Seafood intake in pregnancy has been positively associated with childhood cognitive outcomes which could potentially relate to the high vitamin D content of oily fish. However, whether higher maternal vitamin D status (serum 25-hydroxyvitamin D (25(OH)D)) in pregnancy is associated with a reduced risk of offspring suboptimal neurodevelopmental outcomes is unclear. A total of 7065 mother-child pairs were studied from the Avon Longitudinal Study of Parents and Children cohort who had data for both serum total 25(OH)D concentration in pregnancy and at least one measure of offspring neurodevelopment (pre-school development at 6-42 months; 'Strengths and Difficulties Questionnaire' scores at 7 years; intelligence quotient (IQ) at 8 years; reading ability at 9 years). After adjustment for confounders, children of vitamin D-deficient mothers (<50·0 nmol/l) were more likely to have scores in the lowest quartile for gross-motor development at 30 months (OR 1·20; 95 % CI 1·03, 1·40), fine-motor development at 30 months (OR 1·23; 95 % CI 1·05, 1·44) and social development at 42 months (OR 1·20; 95 % CI 1·01, 1·41) than vitamin D-sufficient mothers (≥50·0 nmol/l). No associations were found with neurodevelopmental outcomes, including IQ, measured at older ages. However, our results suggest that deficient maternal vitamin D status in pregnancy may have adverse effects on some measures of motor and social development in children under 4 years. Prevention of vitamin D deficiency may be important for preventing suboptimal development in the first 4 years of life.

A Birth Cohort Analysis to Study Dog Walking in Adolescence Shows No Relationship with Objectively Measured Physical Activity

Physical inactivity during childhood and adolescence is a serious health concern. There are few studies of the activity undertaken by adolescents when walking with the family dog, and the effect of this on objectively measured physical activity levels. Objective measures of physical activity using accelerometers were recorded at age 11–12, 13–14, and 15–16 years in the Avon Longitudinal Study of Parents and Children (ALSPAC) (ALSPAC, UK) birth cohort during the 2000s. Family pet ownership was collected retrospectively using a questionnaire at age 18 years, for the ages 7, 11, 13, and 15 years. In addition, approximate frequency per week of walks undertaken with dogs were also reported. Multilevel, multivariable modeling was used to investigate the relationship between dog ownership and dog walking status, and physical activity outcomes. There were a total of 4,373 complete data observations for use in 2,055 children. Reported participation in dog walking tended to increase during adolescence, as did dog ownership. The majority of who own dogs reported walking them either 2–6 times/week (range 39–46%) or never (range 27–37%). A small minority (7–8%) reported walking their dog every day. Most reported never walking any other dog either (94–87%). We found no evidence for an association between dog ownership or reported dog walking, and objectively measured physical activity (counts per minute, P = 0.3, or minutes of moderate-to-vigorous physical activity, P = 0.7) during adolescence. This study provides no evidence to support a relationship between adolescent dog ownership and physical activity, and demonstrates the importance of using objective activity measures and considering dog walking rather than just dog ownership.

TRPA1 gene polymorphisms and childhood asthma

BACKGROUND

Animal data have suggested that the transient receptor potential ankyrin-1 (TRPA1) ion channel plays a key role in promoting airway inflammation in asthma and may mediate effects of paracetamol on asthma, yet confirmatory human data are lacking. To study associations of TRPA1 gene variants with childhood asthma and total IgE concentration, and interactions between TRPA1 and prenatal paracetamol exposure on these outcomes.

METHODS

We analysed associations between 31 TRPA1 single nucleotide polymorphisms (SNPs) and current doctor-diagnosed asthma and total IgE concentration at 7.5 years in the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. We sought to confirm the most significant associations with comparable outcomes in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) and Generation R birth cohorts. In ALSPAC, we explored interactions with prenatal paracetamol exposure.

RESULTS

In ALSPAC, there was strong evidence for association between six SNPs and asthma: rs959974 and rs1384001 (per-allele odds ratio for both: 1.30 (95% CI: 1.15-1.47), p = 0.00001), rs7010969 (OR 1.28 (1.13-1.46), p = 0.00004), rs3735945 (OR 1.30 (1.09-1.55), p = 0.003), rs920829 (OR 1.30 (1.09-1.54), p = 0.004) and rs4738202 (OR 1.22 (1.07-1.39), p = 0.004). In a meta-analysis across the three cohorts, the pooled effect estimates confirmed that all six SNPs were significantly associated with asthma. In ALSPAC, TRPA1 associations with asthma were not modified by prenatal paracetamol, although associations with IgE concentration were.

CONCLUSION

This study suggests that TRPA1 may play a role in the development of childhood asthma. (249 words).

The association between maternal postnatal depressive symptoms and offspring sleep problems in adolescence

BACKGROUND

Sleep problems are associated with increased risk of physical and mental illness. Identifying risk factors is an important method of reducing public health impact. We examined the association between maternal postnatal depression (PND) and offspring adolescent sleep problems.

METHOD

The sample was derived from Avon Longitudinal Study of Parents and Children (ALSPAC) participants. A sample with complete data across all variables was used, with four outcome variables. A sensitivity analysis imputing for missing data was conducted (n = 9633).

RESULTS

PND was associated with increased risk of sleep problems in offspring at ages 16 and 18 years. The most robust effects were sleep problems at 18 years [adjusted odds ratio (OR) for a 1 s.d. increase in PND, 1.26, 95% confidence interval (CI) 1.15-1.39, p < 0.001] and waking more often (adjusted OR 1.14, 95% CI 1.05-1.25, p = 0.003). This remained after controlling for confounding variables including antenatal depression and early sleep problems in infancy.

CONCLUSIONS

PND is associated with adolescent offspring sleep problems. Maternal interventions should consider the child's increased risk. Early sleep screening and interventions could be introduced within this group.

Prenatal unhealthy diet, insulin-like growth factor 2 gene (IGF2) methylation, and attention deficit hyperactivity disorder symptoms in youth with early-onset conduct problems

BACKGROUND

Conduct problems (CP) and attention deficit hyperactivity disorder (ADHD) are often comorbid and have each been linked to 'unhealthy diet'. Early-life diet also associates with DNA methylation of the insulin-like growth factor 2 gene (IGF2), involved in fetal and neural development. We investigated the degree to which prenatal high-fat and -sugar diet might relate to ADHD symptoms via IGF2 DNA methylation for early-onset persistent (EOP) versus low CP youth.

METHODS

Participants were 164 youth with EOP (n = 83) versus low (n = 81) CP drawn from the Avon Longitudinal Study of Parents and Children. We assessed if the interrelationships between high-fat and -sugar diet (prenatal, postnatal), IGF2 methylation (birth and age 7, collected from blood), and ADHD symptoms (age 7-13) differed for EOP versus low CP youth.

RESULTS

Prenatal 'unhealthy diet' was positively associated with IGF2 methylation at birth for both the EOP and low CP youth. For EOP only: (a) higher IGF2 methylation predicted ADHD symptoms; and (b) prenatal 'unhealthy diet' was associated with higher ADHD symptoms indirectly via higher IGF2 methylation.

CONCLUSIONS

Preventing 'unhealthy diet' in pregnancy might reduce the risk of ADHD symptoms in EOP youth via lower offspring IGF2 methylation.

Parental suicide attempt and offspring educational attainment during adolescence in the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort

BACKGROUND

Few studies have investigated the impact of parental suicide attempt (SA) on offspring outcomes other than mental health. We investigated the association of parental SA with offspring educational attainment in the Avon Longitudinal Study of Parents and Children (ALSPAC).

METHOD

Parental SA was prospectively recorded from pregnancy until the study children were 11 years old. National school test results (ages 11-16 years) were obtained by record linkage. Multilevel regression models quantified the association between parental SA and offspring outcomes.

RESULTS

Data were available for 6667 mother-child and 3054 father-child pairs. Adolescents whose mothers had attempted suicide were less likely than their peers to achieve the expected educational level by age 14 years [adjusted odds ratio (aOR) 0.63, 95% confidence interval (CI) 0.41-0.95] in models controlling for relevant confounders, including parental education and depression. At age 16 years, adolescents whose mothers had attempted suicide were less likely to obtain the expected educational level (five or more qualifications at grade A*-C) (aOR 0.66, 95% CI 0.43-1.00) in models controlling for relevant confounders and parental education; however, after additionally controlling for maternal depression the results were consistent with chance (aOR 0.74, 95% CI 0.48-1.13). Findings in relation to paternal SA were consistent with those of maternal SA but power was limited due to lower response rate amongst fathers.

CONCLUSIONS

Maternal SA was associated with diminished educational performance at age 14 years. Educational attainment during adolescence can have substantial effect on future opportunities and well-being and these offspring may benefit from interventions.

Association of Genetic Risk for Schizophrenia With Nonparticipation Over Time in a Population-Based Cohort Study

Progress has recently been made in understanding the genetic basis of schizophrenia and other psychiatric disorders. Longitudinal studies are complicated by participant dropout, which could be related to the presence of psychiatric problems and associated genetic risk. We tested whether common genetic variants implicated in schizophrenia were associated with study nonparticipation among 7,867 children and 7,850 mothers from the Avon Longitudinal Study of Parents and Children (ALSPAC; 1991–2007), a longitudinal population cohort study. Higher polygenic risk scores for schizophrenia were consistently associated with noncompletion of questionnaires by study mothers and children and nonattendance at data collection throughout childhood and adolescence (ages 1–15 years). These associations persisted after adjustment for other potential correlates of nonparticipation. Results suggest that persons at higher genetic risk for schizophrenia are likely to be underrepresented in cohort studies, which will underestimate risk of this and related psychiatric, cognitive, and behavioral phenotypes in the population. Statistical power to detect associations with these phenotypes will be reduced, while analyses of schizophrenia-related phenotypes as outcomes may be biased by the nonrandom missingness of these phenotypes, even if multiple imputation is used. Similarly, in complete-case analyses, collider bias may affect associations between genetic risk and other factors associated with missingness.

Associations Between Gestational Age at Birth and Alcohol Use in the Avon Longitudinal Study of Parents and Children

BACKGROUND

The relationship between gestational age at birth (GA) and alcohol use measures in early adulthood was examined in a large U.K. community-based birth cohort (Avon Longitudinal Study of Parents and Children).

METHODS

A series of linear and logistic regression models were used to test for main effects of a continuous measure of GA on a range of alcohol use measures, and moderation of these associations by sex. In addition, mediation analyses assessed the extent to which significant associations between GA and alcohol use operated indirectly, through influences of the parental environment and/or childhood measures of emotional and behavioral health (EBH).

RESULTS

Earlier GA significantly predicted never drinking by age 18, but was not associated with other measures of alcohol use behavior among young adult drinkers (i.e., Self-Rating of the Effects of Alcohol, Alcohol Use Disorders Identification Test, or DSM-IV-TR Criteria for Alcohol Dependence). The association between earlier GA and never drinking by age 18 was moderated by sex, such that females born early were less likely to have ever had a drink by age 18. In the full sample, childhood measures of EBH were found to mediate the association between earlier GA and never drinking by age 18. This association was not mediated by parenting factors.

CONCLUSIONS

Earlier GA is associated with never drinking alcohol in early adulthood, in females. Emotional and behavioral difficulties experienced in early childhood may mediate the relationship between earlier GA and never drinking by age 18.

A prospective longitudinal model predicting early adult alcohol problems: evidence for a robust externalizing pathway

BACKGROUND

Risk factors for alcohol problems (AP) include biological and environmental factors that are relevant across development. The pathways through which these factors are related, and how they lead to AP, are optimally considered in the context of a comprehensive developmental model.

METHOD

Using data from a prospectively assessed, population-based UK cohort, we constructed a structural equation model that integrated risk factors reflecting individual, family and peer/community-level constructs across childhood, adolescence and young adulthood. These variables were used to predict AP at the age of 20 years.

RESULTS

The final model explained over 30% of the variance in liability to age 20 years AP. Most prominent in the model was an externalizing pathway to AP, with conduct problems, sensation seeking, AP at age 17.5 years and illicit substance use acting as robust predictors. In conjunction with these individual-level risk factors, familial AP, peer relationships and low parental monitoring also predicted AP. Internalizing problems were less consistently associated with AP. Some risk factors previously identified were not associated with AP in the context of this comprehensive model.

CONCLUSIONS

The etiology of young adult AP is complex, influenced by risk factors that manifest across development. The most prominent pathway to AP is via externalizing and related behaviors. These findings underscore the importance of jointly assessing both biologically influenced and environmental risk factors for AP in a developmental context.

The association between maternal-reported responses to infant crying at 4 weeks and 6 months and offspring depression at 18: a longitudinal study

The purpose of the present study is to examine the association between maternal response to infant crying and the psychological health of the child in later life. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort, consisting of 15,247 pregnancies, 10,278 with exposure variables and 3201 complete cases were identified as having exposure, covariate and outcome data. Using a postal questionnaire, mothers were asked regarding their infant at 4 weeks and 6 months, 'If they cry what do you do?': (a) pick them up immediately; (b) if they cry, leave them for a while, and if they do not stop, pick them up; or (c) never pick them up until you are ready. Outcome was an International Statistical Classification-10th revision criteria (ICD-10) diagnosis of depression at 18 years for the infant. Offspring of mothers who at 4 weeks reported that they never picked their infants up until they were ready were more likely to have depression at 18 years (OR = 2.06, CI 0.95-4.47, adjusted for sociodemographic confounding variables). There was no evidence for an association at 6 months. Including adjustment variables reduced the strength of our association; an observed objective measure of maternal response rather than a self-report may have more accurately determined the mother's actual responses. There is some evidence for an association between maternal reporting of responses to infant crying at 4 weeks and risk of developing depression at 18 years. If this association is found to be causal, interventions encouraging mothers to represent and respond to their infants' emotional states may help prevent offspring depression.