Avon Longitudinal Study Of Parents And Children Research Articles

Metabolome-wide Mendelian randomization for age at menarche and age at natural menopause.

The role of metabolism in the variation of age at menarche (AAM) and age at natural menopause (ANM) in the female population is not entirely known. We aimed to investigate the causal role of circulating metabolites in AAM and ANM using Mendelian randomization (MR). We combined MR with genetic colocalization to investigate potential causal associations between 658 metabolites and AAM and between 684 metabolites and ANM. We extracted genetic instruments for our exposures from four genome-wide association studies (GWAS) on circulating metabolites and queried the effects of these variants on the outcomes in two large GWAS from the ReproGen consortium. Additionally, we assessed the mediating role of the body mass index (BMI) in these associations, identified metabolic pathways implicated in AAM and ANM, and sought validation for selected metabolites in the Avon Longitudinal Study of Parents and Children (ALSPAC). Our analysis identified 10 candidate metabolites for AAM, but none of them colocalized with AAM. For ANM, 76 metabolites were prioritized (FDR-adjusted MR P-value ≤ 0.05), with 17 colocalizing, primarily in the glycerophosphocholines class, including the omega-3 fatty acid and phosphatidylcholine (PC) categories. Pathway analyses and validation in ALSPAC mothers also highlighted the role of omega and polyunsaturated fatty acids levels in delaying age at menopause. Our study suggests that metabolites from the glycerophosphocholine and fatty acid families play a causal role in the timing of both menarche and menopause. This underscores the significance of specific metabolic pathways in the biology of female reproductive longevity.

The association between sexual orientation and psychotic like experiences during adolescence: a prospective cohort study.

Psychotic like experiences (PLEs) are relatively common during adolescence and associated with a range of negative outcomes. There is evidence that sexual minorities are at increased risk of mental health problems including depression, anxiety, self-harm and suicidality. However, no study has investigated the association between sexual orientation and psychotic experiences during adolescence. We compared trajectories of PLEs in sexual minority and heterosexual adolescents from 12 to 24years of age. We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC). Participants provided data on sexual orientation at age 16 and PLEs at ages 12, 17 and 24. We used multi-level logistic regression models to test associations between sexual orientation and PLEs, before and after adjusting for covariates. We investigated whether the association differed according to time-point and sex using interaction terms. We found evidence that the odds of PLEs were 2.35 times (95% Confidence Interval 1.79-3.06, p < 0.0001) higher among sexual minority compared with heterosexual adolescents, across all ages, after adjusting for covariates. There was no evidence that the association between sexual orientation and PLEs differed according to time-point (p = 0.50) or sex (p = 0.29). We found an increased risk of psychosis in sexual minorities compared with heterosexuals, which was present from around 12years of age and persisted until age 24. Early interventions to prevent this mental health inequality could include universal interventions to promote inclusivity and acceptance of diverse sexual orientations.

Disagreement concerning atopic dermatitis subtypes between an English prospective cohort (ALSPAC) and linked electronic health records.

Subtypes of atopic dermatitis (AD) have been derived from the Avon Longitudinal Study of Parents and Children (ALSPAC) based on presence and severity of symptoms reported in questionnaires (Severe-Frequent, Moderate-Frequent, Moderate-Declining, Mild-Intermittent, Unaffected/Rare). Good agreement between ALSPAC and linked electronic health records (EHRs) would increase trust in the clinical validity of these subtypes and allow inferring subtypes from EHRs alone, which would enable their study in large primary care databases. 1. Explore if presence and number of AD records in EHRs agrees with AD symptom and severity reports from ALSPAC; 2. Explore if EHRs agree with ALSPAC-derived AD subtypes; 3. Construct models to classify ALSPAC-derived AD subtype using EHRs. We used data from the ALSPAC prospective cohort study from 11 timepoints until age 14 years (1991-2008), linked to local general practice EHRs. We assessed how far ALSPAC questionnaire responses and derived subtypes agreed with AD as established in EHRs using different AD definitions (e.g., diagnosis and/or prescription) and other AD-related records. We classified AD subtypes using EHRs, fitting multinomial logistic regression models tuning hyperparameters and evaluating performance in the testing set (ROC AUC, accuracy, sensitivity, and specificity). 8,828 individuals out of a total 13,898 had both been assigned an AD subtype and had linked EHRs. The number of AD-related codes in EHRs generally increased with severity of AD subtype, however not all with the Severe-Frequent subtypes had AD in EHRs, and many with the Unaffected/Rare subtype did have AD in EHRs. When predicting ALSPAC AD subtype using EHRs, the best tuned model had ROC AUC of 0.65, sensitivity of 0.29 and specificity of 0.83 (both macro averaged); when different sets of predictors were used, individuals with missing EHR coverage excluded, and subtypes combined, sensitivity was not considerably improved. ALSPAC and EHRs disagreed not just on AD subtypes, but also on whether children had AD or not. Researchers should be aware that individuals considered as having AD in one source may not be considered as having AD in another.

Sexual experiences and behaviours in the offspring generation of the Avon Longitudinal Study of Parents and Childhood

Previous research on child/teenage sexual experiences has largely focussed on negative outcomes such as teen pregnancy or acquiring sexually transmitted infections and are mainly cross-sectional. Longitudinal research is required to assess normal sexual development and the attainment of psychologically healthy attitudes towards sexuality. The Avon Longitudinal Study of Parents and Children (ALSPAC) has administered questions on relationships and sexual experiences from the age of 11 years to the index children. This data note describes these data.

Behavioural, psychiatric, and cognitive phenotypes associated with numbers of repeats of the FRAXE allele on the FMR2 gene

Background The FRAXE site on the X-chromosome has a variable number of trinucleotide repeats. The rare condition Fragile XE has &gt;200 repeats, but most X chromosomes have &lt;60 such repeats, with evidence of a bimodal distribution. It is known that when the number of repeats is &lt;60, the repeat number can increase from mother to son, which raises the question as to whether there is an evolutionary advantage in the size of these repeats. This paper investigates whether the higher of the &lt;60 repeats are associated with neurocognitive differences among boys in a general population. We hypothesised that although there was previous evidence of a link between higher numbers of repeats in the boys in this population with maternal grandmothers with schizophrenia, there may be cognitive or behavioural advantages to their grandsons of increased levels of repeats. Methods We compared 1951 behavioural, psychiatric, and cognitive outcomes of 5060 boys from the Avon Longitudinal Study of Parents and Children (ALSPAC) using a phenome scan. Results We found that boys with relatively high levels of repeats (&gt;24) had a higher risk of certain neurocognitive outcomes (P&lt;0.01). Boys with &gt;24 repeats were more likely to report: (a) psychosis-like experiences; (b) increased ability to recognise facial signs of anger; (c) increased risk of eating disorders; (d) increased likelihood of smoking cigarettes and using illicit drugs during adolescence than would be expected by chance. There was no sign of associations with cognitive abilities. Conclusions We concluded that there was little evidence that higher levels of the normal range of FRAXE repeats were associated with a difference in cognitive abilities, but there was evidence of increased reports of psychotic-like experiences and other behaviour problems in this group. There was no evidence of evolutionary neurocognitive advantage.

Shorter night-time sleep duration and later sleep timing from infancy to adolescence.

Here, we (a) examined the trajectories of night-time sleep duration, bedtime and midpoint of night-time sleep (MPS) from infancy to adolescence, and (b) explored perinatal risk factors for persistent poor sleep health. This study used data from 12,962 participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Parent or self-reported night-time sleep duration, bedtime and wake-up time were collected from questionnaires at 6, 18 and 30 months, and at 3.5, 4-5, 5-6, 6-7, 9, 11 and 15-16 years. Child's sex, birth weight, gestational age, health and temperament, together with mother's family adversity index (FAI), age at birth, prenatal socioeconomic status and postnatal anxiety and depression, were included as risk factors for persistent poor sleep health. Latent class growth analyses were applied first to detect trajectories of night-time sleep duration, bedtime and MPS, and we then applied logistic regressions for the longitudinal associations between risk factors and persistent poor sleep health domains. We obtained four trajectories for each of the three sleep domains. In particular, we identified a trajectory characterized by persistent shorter sleep, a trajectory of persistent later bedtime and a trajectory of persistent later MPS. Two risk factors were associated with the three poor sleep health domains: higher FAI with increased risk of persistent shorter sleep (OR = 1.20, 95% CI = 1.11-1.30, p < .001), persistent later bedtime (OR = 1.28, 95% CI = 1.19-1.39, p < .001) and persistent later MPS (OR = 1.30, 95% CI = 1.22-1.38, p < .001); and higher maternal socioeconomic status with reduced risk of persistent shorter sleep (OR = 0.99, 95% CI = 0.98-1.00, p = .048), persistent later bedtime (OR = 0.98, 95% CI = 0.97-0.99, p < .001) and persistent later MPS (OR = 0.99, 95% CI = 0.98-0.99, p < .001). We detected trajectories of persistent poor sleep health (i.e. shorter sleep duration, later bedtime and later MPS) from infancy to adolescence, and specific perinatal risk factors linked to persistent poor sleep health domains.

Developmental epigenomic effects of maternal financial problems.

Early-life adversity as neglect or low socioeconomic status is associated with negative physical/mental health outcomes and plays an important role in health trajectories through life. The early-life environment has been shown to be encoded as changes in epigenetic markers that are retained for many years.We investigated the effect of maternal major financial problems (MFP) and material deprivation (MD) on their children's epigenome in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Epigenetic aging, measured with epigenetic clocks, was weakly accelerated with increased MFP. In subsequent EWAS, MFP, and MD showed strong, independent programing effects on children's genomes. MFP in the period from birth to age seven was associated with genome-wide epigenetic modifications on children's genome visible at age 7 and partially remaining at age 15.These results support the hypothesis that physiological processes at least partially explain associations between early-life adversity and health problems later in life. Both maternal stressors (MFP/MD) had similar effects on biological pathways, providing preliminary evidence for the mechanisms underlying the effects of low socioeconomic status in early life and disease outcomes later in life. Understanding these associations is essential to explain disease susceptibility, overall life trajectories and the transition from health to disease.

The relationship between type, timing and duration of exposure to adverse childhood experiences and adolescent self-harm and depression: findings from three UK prospective population-based cohorts.

Adverse childhood experiences (ACEs) are well-established risk factors for self-harm and depression. However, despite their high comorbidity, there has been little focus on the impact of developmental timing and the duration of exposure to ACEs on co-occurring self-harm and depression. Data were utilised from over 22,000 children and adolescents participating in three UK cohorts, followed up longitudinally for 14-18 years: the Avon Longitudinal Study of Parents and Children (ALSPAC), the Millennium Cohort Study (MCS) and the Environmental Risk (E-Risk) Longitudinal Twin Study. Multinomial logistic regression models estimated associations between each ACE type and a four-category outcome: no self-harm or depression, self-harm alone, depression alone and self-harm with co-occurring depression. A structured life course modelling approach was used to examine whether the accumulation (duration) of exposure to each ACE, or a critical period (timing of ACEs) had the strongest effects on self-harm and depression in adolescence. The majority of ACEs were associated with co-occurring self-harm and depression, with consistent findings across cohorts. The importance of timing and duration of ACEs differed across ACEs and across cohorts. For parental mental health problems, longer duration of exposure was strongly associated with co-occurring self-harm and depression in both ALSPAC (adjusted OR: 1.18, 95% CI: 1.10-1.25) and MCS (1.18, 1.11-1.26) cohorts. For other ACEs in ALSPAC, exposure in middle childhood was most strongly associated with co-occurring self-harm and depression, and ACE occurrence in early childhood and adolescence was more important in the MCS. Efforts to mitigate the impact of ACEs should start in early life with continued support throughout childhood, to prevent long-term exposure to ACEs contributing to risk of self-harm and depression in adolescence.

Spiritual and religious beliefs and behaviour: data collected from 27/28-year-old offspring in the Avon Longitudinal Study of Parents and Children, 2019-2020.

Religious/spiritual belief and practices have sometimes been demonstrated to have positive associations with outcomes such as coping with serious illness, anxiety, depression, negative life events and general well-being, and therefore warrants consideration in many facets of health research. For example, increasing secularisation evidenced, particularly in the West, may reflect increasing rates of depression and anxiety. Very few studies have charted the ways in which religious/spiritual beliefs and practices of parents and their offspring vary longitudinally or between generations. Avon Longitudinal Study of Parents and Children (ALSPAC) is one such study that can relate belief and practices with aspects of physical and mental health and/or distinguish the different facets of the environment that may influence the development, or inter-generational loss, of belief and behaviours. This paper describes the 2019–2020 data collection in the ALSPAC on the religious/spiritual beliefs and behaviours (RSBB) of the study offspring (born 1991/1992) at ages 27–28 years. Previously collected and new data on the offspring are described here and comparisons are made with identical data completed by their parents (mothers and their partners) in early 2020. The most striking observations are that in almost all aspects of RSBB the offspring of both sexes are more secular, especially when compared with their mothers. For example, 56.2% of offspring state that they do not believe in God, or a divine power compared with 26.6% of mothers and 45.3% of mothers’ partners. When asked about their type of religion, 65.4% of participants stated ‘none’, compared with 27.2% of mothers and 40.2% of partners. This confirms previous research reporting increasing secularisation from one generation to the next. As with the mothers and their partners, female offspring were more likely than males to believe in a divine power and to practice their beliefs.

Smoking during pregnancy and its effect on placental weight: a Mendelian randomization study

BackgroundThe causal relationship between maternal smoking in pregnancy and reduced offspring birth weight is well established and is likely due to impaired placental function. However, observational studies have given conflicting results on the association between smoking and placental weight. We aimed to estimate the causal effect of newly pregnant mothers quitting smoking on their placental weight at the time of delivery.MethodsWe used one-sample Mendelian randomization, drawing data from the Avon Longitudinal Study of Parents and Children (ALSPAC) (N = 690 to 804) and the Norwegian Mother, Father and Child Cohort Study (MoBa) (N = 4267 to 4606). The sample size depends on the smoking definition used for different analyses. The analysis was performed in pre-pregnancy smokers only, due to the specific role of the single-nucleotide polymorphism (SNP) rs1051730 (CHRNA5 – CHRNA3 – CHRNB4) in affecting smoking cessation but not initiation.ResultsFixed effect meta-analysis showed a 182 g [95%CI: 29,335] higher placental weight for pre-pregnancy smoking mothers who continued smoking at the beginning of pregnancy, compared with those who stopped smoking. Using the number of cigarettes smoked per day in the first trimester as the exposure, the causal effect on placental weight was 11 g [95%CI: 1,21] per cigarette per day. Similarly, smoking at the end of pregnancy was causally associated with higher placental weight. Using the residuals of birth weight regressed on placental weight as the outcome, we showed evidence of lower offspring birth weight relative to the placental weight, both for continuing smoking at the start of pregnancy as well as continuing smoking throughout pregnancy (change in z-score birth weight adjusted for z-score placental weight: -0.8 [95%CI: -1.6,-0.1]).ConclusionOur results suggest that continued smoking during pregnancy causes higher placental weights.

Association of early-life exposure to air and noise pollution with youth mental health: findings from the ALSPAC cohort

BackgroundIncreasing evidence suggests that air pollution exposure contributes to the development of mental health problems, including psychosis and depression. However, little is known about the importance of early-life exposure, nor the potential role of noise pollution, a correlate of air pollution. We examined the association of exposure to air and noise pollution from pregnancy to age 12 years with three mental health problems assessed at ages 12, 18, and 24 years. MethodsData were from the Avon Longitudinal Study of Parents and Children (ALSPAC), which tracks the development of about 14 000 babies who had expected delivery dates between April 1, 1991, and Dec 31, 1992, in Avon, UK. This was linked with novel data on nitrogen dioxide, PM2·5, and noise pollution in pregnancy, childhood (ages 1–9 years), and adolescence (ages 10–12 years). Psychotic experiences, depression, and anxiety were measured at ages 12, 18, and 24 years. Logistic regression models were controlled for individual-level, family-level, and area-level confounders, and e-values were calculated to estimate residual confounding. FindingsParticipants exposed to higher PM2.5, particularly during pregnancy, had greater odds for psychotic experiences (adjusted odds ratio 1·17 [95% CI 1·05–1·30]) and depression (1·11 [1·01–1·22]). There was little evidence associating nitrogen dioxide or noise pollution with psychotic experiences or depression. Conversely, higher nitrogen dioxide (but not PM2·5) exposure in pregnancy (1·16 [1·01–1·33]), and higher noise pollution in childhood (1·20 [1·06-1·37]) and adolescence (1·17 [1·02-1·35]), were associated with greater odds for anxiety. InterpretationOur study builds on evidence linking air pollution to psychosis and depression and provides rare longitudinal evidence linking noise pollution to anxiety. Our findings indicate that air pollution exposure earlier in development (eg, during pregnancy) might be particularly important, and suggest a degree of specificity in terms of pollutant-outcome associations. If causal, our findings suggest that interventions to reduce air pollution would improve global mental health. FundingWellcome Trust, UK Medical Research Council–Wellcome, and University of Bristol.

The mother during pregnancy and the puerperium: Detailed data abstracted from the clinical obstetric records of ALSPAC pregnancies

Background When the Avon Longitudinal Study of Parents and Children (ALSPAC) was planned, it was assumed that the clinical obstetric data would be easily accessible from the newly developed National Health Service computerised ‘STORK’ system. Pilot studies, however, showed that, although fairly accurate in regard to aspects of labour and delivery, it was, at the time (1990-2), inadequate for identifying the full antenatal and postnatal details of clinical complications and treatments of the women in the Study. Methods A scheme was therefore developed to train research staff to find and abstract relevant details from clinical records onto proformas designed for the purpose. Extracting such data proved very time consuming (up to six hours for complicated pregnancies) and consequently expensive. Funding for the enterprise was obtained piecemeal using specific focussed grants to extract data for subsamples of the Study, including a random sample to serve as controls. Results To date, detailed records have been completed for 8369 pregnancies, and a further 5336 (13,705 in total) have complete details on specific prenatal areas, including serial measures of maternal blood pressure, proteinuria and weight. In this Data Note we describe the information abstracted from the obstetric medical records concerning the mother during pregnancy, labour, delivery and the first two weeks of the puerperium. Information abstracted relating to the fetus (including fetal monitoring, presentation, method of delivery) and neonate (signs of asphyxia, resuscitation, treatment and well-being) have been described in a further Data Note. Conclusions These data add depth to ALSPAC concerning ways in which the signs and symptoms, procedures and treatments of the mother prenatally, intrapartum and postnatally, may impact on the long-term health and development of both mother and child. They augment the data collected from the mothers’ questionnaires (described elsewhere) and the ‘STORK’ digital hospital data.

Epigenetic Features in Newborns Associated with Preadolescence Lung Function and Asthma Acquisition during Adolescence.

The study was based on the Isle of Wight Birth cohort (IOWBC). Female subjects with DNAm data at birth and with no asthma at age 10 years were included (n = 249). The R package ttScreening was applied to identify CpGs potentially associated with AA from 10 to 18 years and with LF at age 10 (FEV1, FVC, and FEV1/FVC), respectively. Agreement in identified CpGs between AA and LF was examined, along with their biological pathways and processes via the R function gometh. We tested the findings in an independent cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC), to examine overall replicability. In IOWBC, 292 CpGs were detected with DNAm associated with AA and 1517 unique CpGs for LF (514 for FEV1, 436 for FVC, 408 for FEV1/FVC), with one overlapping CpG, cg23642632 (NCKAP1) between AA and LF. Among the IOWBC-identified CpGs, we further tested in ALSPAC and observed the highest agreement between the two cohorts in FVC with respect to the direction of association and statistical significance. Epigenetic enrichment analyses indicated non-specific connections in the biological pathways and processes between AA and LF. The present study suggests that FEV1, FVC, and FEV1/FVC (as objective measures of LF) and AA (incidence of asthma) are likely to have their own specific epigenetic features and biological pathways at birth. More replications are desirable to fully understand the complexity between DNAm, lung function, and asthma acquisition.

Exploring associations between the Big Five personality traits and cognitive ability with COVID-19 vaccination hesitancy and uptake among mothers and offspring in a UK prospective cohort study

BackgroundVaccines reduce the severity of symptoms, and risk of hospitalisation and death from infectious diseases. Yet, vaccination hesitancy persists. Research identifying psychological risk factors for vaccination hesitancy is limited and reports conflicting results. This study sought to address these inconsistencies and explore the role of personality and cognitive ability in COVID-19 vaccination hesitancy and uptake in a prospective cohort study. MethodsData came from young adults (Generation-1; G1) and their mothers (Generation-0; G0) in the Avon Longitudinal Study of Parents and Children (ALSPAC). Multinomial logistic regressions, adjusting for several sociodemographic confounders, were used to explore whether personality and cognitive ability were associated with COVID-19 vaccination hesitancy and uptake. 4,960 G1 and 4,853 G0 mothers were included in the study population. FindingsAmong G1, 38.4% exhibited vaccination hesitancy, yet 91.9% of the cohort received the vaccine. In adjusted models, higher levels of openness, agreeableness, conscientiousness, and cognitive ability were associated with an increased probability of wanting the vaccine. Similarly, higher levels of agreeableness, openness and cognitive ability were associated with an increased probability of vaccination uptake. However, the evidence of associations with vaccine uptake were generally weaker than with vaccination hesitancy. 56.7% of the offspring who did not want the vaccine either received the vaccine or intended to, whilst 43.3% still had no intention.Among G0 mothers, 25.6% were vaccination hesitant, yet 99.0% of the cohort received the vaccine. 3.1% said they did not want the vaccine; approximately 80% of these either received the vaccine or intended to. We found inconclusive evidence for an association between cognitive ability and vaccination hesitancy among G0 mothers. InterpretationThis study identified psychological factors associated with vaccination hesitancy and uptake. If these associations are causal, these findings may help design more effective vaccination hesitancy interventions.

Paternal health in the first 12-13 years of the ALSPAC study

The Avon Longitudinal Study of Parents and Children (ALSPAC) collected information from the enrolled pregnancy onwards to identify features of the environment in which the study child was brought up. Among data collected were features concerning the health of the mothers’ partners – generally the study father. This was an important feature since the father’s physical and mental health can have a long-term effect on the family. In this Data Note we describe the data available on the father’s health from pregnancy until 12 years after the offspring was born. Not only is this a valuable addition to the environmental information available for studies of the child’s development and the mental health of the mother over time, but it will provide a useful description of the father himself during adulthood.

The ALSPAC fetal and neonatal resource: detailed data abstracted from the clinical records of the new-born

In a previous Data Note, we outlined the data obtained from clinical obstetric records concerning many details of the pregnancies resulting in the births of the children in the Avon Longitudinal Study of Parents and Children (ALSPAC). Here we describe the data that have been abstracted from medical records concerning the fetus and neonate. Full details concerning the selection biases regarding the data abstracted are outlined in the previous Data Note. The records that have been abstracted, and described in this Data Note, concern the health of the fetus (measured in relation to the results of fetal monitoring, presentation at various stages of pregnancy, and the method of delivery) as well as the status of the newborn immediately post-delivery. Details of signs, symptoms and treatments of this population of new-born babies, as recorded in the clinical records, are described for the time during which they were in hospital or under the care of a designated midwife. These data add depth to the information collected from elsewhere concerning this period of the child’s life: from the questionnaires completed at the time by the mother; and clinical details from neonatal intensive or special care units which will be detailed in a further Data Note.

Releasing synthetic data from the Avon Longitudinal Study of Parents and Children (ALSPAC): Guidelines and applied examples

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a prospective birth cohort. Since its inception in the early 1990s, the study has collected over thirty years of data on approximately 15,000 mothers, their partners, and their offspring, resulting in over 100,000 phenotype variables to date. Maintaining data security and participant anonymity and confidentiality are key principles for the study, meaning that data access is restricted to bona fide researchers who must apply to use data, which is then shared on a project-by-project basis. Despite these legitimate reasons for restricting data access, this does run counter to emerging best scientific practices encouraging making data openly available to facilitate transparent and reproducible research. Given the rich nature of the resource, ALSPAC data are also a valuable educational tool, used for teaching a variety of methods, such as longitudinal modelling and approaches to modelling missing data. To support these efforts and to overcome the restrictions in place with the study’s data sharing policy, we discuss methods for generating and making openly available synthesised ALSPAC datasets; these synthesised datasets are modelled on the original ALSPAC data, thus maintaining variable distributions and relations among variables (including missing data) as closely as possible, while at the same time preserving participant anonymity and confidentiality. We discuss how ALSPAC data can be synthesised using the ‘synthpop’ package in the R statistical programming language (including an applied example), present a list of guidelines for researchers wishing to release such synthesised ALSPAC data to follow, and demonstrate how this approach can be used as an educational tool to illustrate longitudinal modelling methods.

Later eating rhythm measured in children at 7 years of age in the ALSPAC cohort

Later eating rhythm (LER) refers to later timing, greater energy intake (EI), and higher frequency of eating occasions (meal/snack) in the evening. The significance of LER in child health is becoming increasingly recognised. However, the lack of consensus regarding the definition of LER makes it challenging to fully comprehend its role. This data note describes LER variables derived in the Avon Longitudinal Study of Parents and Children (ALSPAC). ALSPAC is an ongoing birth cohort which enrolled 14,541 pregnant women living in Avon, UK, with an expected date of delivery between April 1991 and December 1992. When children were aged 7 years, parents completed a structured 3-day food diary, recording all foods/drinks consumed over 3 days (preferably 1 weekend day and 2 weekdays). Data was available for 7,285 children (50.1% response rate). A subsample of 4,869 children had exact time of eating occasions added to the existing database, which only included broad indications of eating timing based on 2-7 hour long meal slots. 13 LER variables were derived for the entire week and weekdays/weekend days separately. These comprise: 1) eating around individual bedtime (yes/no); 2) eating around average bedtime (yes/no); 3) time of evening main meal (hrs:mins); 4) time of last eating occasion (hrs:mins); 5) EI in the evening (percentage of total daily energy intake, %TDEI); 6) EI within 2hrs before bedtime (%TDEI); 7) EI for evening main meal (%TDEI); 8) EI for evening snacks (%TDEI); 9) eating over 30% of total daily energy intake after 18:00 (yes/no); 10) eating over 25% of total daily energy intake within 2hrs before bedtime (yes/no); 11) eating frequency after 17:00 (number of eating occasions); 12) regularity of dinner (number of days having dinner); 13) frequency of evening snacks (number of days having evening snacks). We describe the derivation, prevalence and inter-corelations between LER variables.

Measures of puberty in the Avon Longitudinal Study of Parents and Children (ALSPAC) offspring cohort

Background When studying the development of children through the preteen years into adolescence, it is often important to link features of their physical and mental health to the stage of puberty at the time. This is complex since individuals vary substantially in the ages at which they reach different pubertal milestones. Methods The Avon Longitudinal Study of Parents and Children (ALSPAC) is an ongoing longitudinal cohort study based in southwest England that recruited over 14000 women in pregnancy, with expected dates of delivery between April 1991 and December 1992. From 1999, information on puberty was collected using a number of different methods : (a) A series of annual questionnaires were administered when the index children were aged between eight and 17 years; these were mainly concerned with the physical changes associated with puberty; (b) identification of the age at peak height growth using the SITAR methodology; and (c) retrospective information from the girls on their age at onset of menstruation (menarche). Results The advantages and disadvantages of each method are discussed. Conclusions The data are available for analysis by interested researchers.

Inflammation proteomics datasets in the ALSPAC cohort

Proteomics is the identification, detection and quantification of proteins within a biological sample. The complete set of proteins expressed by an organism is known as the proteome. The availability of new high-throughput proteomic technologies, such as Olink Proteomic Proximity Extension Assay (PEA) technology has enabled detailed investigation of the circulating proteome in large-scale epidemiological studies. In particular, the Olink® Target 96 inflammatory panel allows the measurement of 92 circulating inflammatory proteins. The Avon Longitudinal Study of Parents and Children (ALSPAC) is a prospective population-based cohort study which recruited pregnant women in 1991-1992 and has followed these women, their partners, and their offspring ever since. In this data note, we describe the newly-released proteomic data available in ALSPAC. Ninety-two proteins were analysed in 9000 blood plasma samples using the Olink® Target 96 inflammatory panel. Samples were derived from 2968 fasted mothers (mean age 47.5; Focus on Mothers 1 (FOM1)), 3005 non-fasted offspring at age 9 (Focus@9) and 3027 fasted offspring at age 24 (Focus@24). Post sample filtering, 1834 offspring have data at both timepoints and 1119 of those have data from their mother available. We performed quality control analyses using a standardised data processing workflow (metaboprep) to produce a filtered dataset of 8983 samples for researchers to use in future analyses. Initial validation analyses indicate that IL-6 measured using the Olink® Target 96 inflammatory panel is highly correlated with IL-6 previously measured by clinical chemistry (Pearson’s correlation = 0.77) and we are able to reproduce the reported positive correlation between body mass index (BMI) and IL-6. The pre-processing and validation analyses indicate a rich proteomic dataset to further characterise the role of inflammation in health and disease.