A5022945304- Birth, Development, and Health
- Health, Environment, Cognitive Aging
- Obesity, Physical Activity, Diet
- Genetic Associations and Epidemiology
- Advanced Causal Inference Techniques
- Health disparities and outcomes
- Nutritional Studies and Diet
- Statistical Methods and Bayesian Inference
- Gestational Diabetes Research and Management
- Pregnancy and preeclampsia studies
- Epigenetics and DNA Methylation
- Acute Ischemic Stroke Management
- Health Systems, Economic Evaluations, Quality of Life
- Genetic and phenotypic traits in livestock
- Stroke Rehabilitation and Recovery
- Physical Activity and Health
- Genetic Mapping and Diversity in Plants and Animals
- Attention Deficit Hyperactivity Disorder
- Child Nutrition and Water Access
- Prostate Cancer Diagnosis and Treatment
- Statistical Methods and Inference
- Child and Adolescent Psychosocial and Emotional Development
- Statistical Methods in Clinical Trials
- Prostate Cancer Treatment and Research
- Neonatal Respiratory Health Research
MRC Epidemiology Unit
2016-2025
University of Bristol
2016-2025
Medical Research Council
2015-2024
University Hospitals Bristol NHS Foundation Trust
2014-2024
National Institute for Health Research
2014-2024
NIHR Bristol Biomedical Research Centre
2018-2024
MRC Integrative Epidemiology Unit
2015-2024
University Hospitals Bristol and Weston NHS Foundation Trust
2021-2024
NIHR Clinical Research Network
2023
At Bristol
2018-2022
Summary The Avon Longitudinal Study of Children and Parents (ALSPAC) was established to understand how genetic environmental characteristics influence health development in parents children. All pregnant women resident a defined area the South West England, with an expected date delivery between 1st April 1991 31st December 1992, were eligible 13 761 (contributing 867 pregnancies) recruited. These have been followed over last 19–22 years completed up 20 questionnaires, had detailed data...
Inference about the causal structure that induces correlations between two traits can be achieved by combining genetic associations with a mediation-based approach, as is done in inference test (CIT). However, we show measurement error phenotypes lead to CIT inferring wrong direction, and increasing sample sizes has adverse effect of confidence answer. This problem likely general other approaches. Here introduce an extension Mendelian randomisation, method uses instrumentation framework,...
Triangulation is the practice of obtaining more reliable answers to research questions through integrating results from several different approaches, where each approach has key sources potential bias that are unrelated other. With respect causal in aetiological epidemiology, if approaches all point same conclusion, this strengthens confidence finding. This particularly case when some would predict findings opposite directions they were due such biases. Where there inconsistencies,...
ObjectivesResearchers are concerned whether multiple imputation (MI) or complete case analysis should be used when a large proportion of data missing. We aimed to provide guidance for drawing conclusions from with missingness.Study Design and SettingVia simulations, we investigated how the missing data, fraction information (FMI), availability auxiliary variables affected MI performance. Outcome were completely at random (MAR).ResultsProvided sufficient was available; beneficial in terms...
Abstract Numerous observational studies have attempted to identify risk factors for infection with SARS-CoV-2 and COVID-19 disease outcomes. Studies used datasets sampled from patients admitted hospital, people tested active infection, or who volunteered participate. Here, we highlight the challenge of interpreting evidence such non-representative samples. Collider bias can induce associations between two more variables which affect likelihood an individual being sampled, distorting these in...
Large-scale cross-sectional and cohort studies have transformed our understanding of the genetic environmental determinants health outcomes. However, representativeness these samples may be limited–either through selection into studies, or by attrition from over time. Here we explore potential impact this bias on results obtained perspective that amounts to conditioning a collider (i.e. form bias). Whereas it is acknowledged will strong effect prevalence estimates, often assumed should not...
Abstract Background Missing data are unavoidable in epidemiological research, potentially leading to bias and loss of precision. Multiple imputation (MI) is widely advocated as an improvement over complete case analysis (CCA). However, contrary widespread belief, CCA preferable MI some situations. Methods We provide guidance on choice when incomplete. Using causal diagrams depict missingness mechanisms, we describe will not be biased by missing compare CCA, with respect efficiency, a range...
<h3>Objective:</h3> To measure the levels and patterns of physical activity, using accelerometers, 11-year-old children participating in Avon Longitudinal Study Parents Children (ALSPAC). <h3>Design:</h3> Cross-sectional analysis. <h3>Setting:</h3> ALSPAC is a birth cohort study located former county Avon, southwest England. This used data collected when were 11 years old. <h3>Participants:</h3> 5595 (2662 boys, 2933 girls). The are offspring women recruited to during 1991–2. median age (95%...
We sought to examine the association of gestational weight gain (GWG) and prepregnancy with offspring adiposity cardiovascular risk factors.Data from 5154 (for blood pressure) 3457 assays) mother-offspring pairs a UK prospective pregnancy cohort were used. Random-effects multilevel models used assess incremental GWG (median range repeat measures per woman: 10 [1, 17]). Women who exceeded 2009 Institute Medicine-recommended more likely have greater body mass index, waist, fat mass, leptin,...
Background The COVID-19 pandemic and mitigation measures are likely to have a marked effect on mental health. It is important use longitudinal data improve inferences. Aims To quantify the prevalence of depression, anxiety well-being before during pandemic. Also, identify groups at risk depression and/or Method Data were from Avon Longitudinal Study Parents Children (ALSPAC) index generation ( n = 2850, mean age 28 years) parent 3720, 59 years), Generation Scotland 4233, years). Depression...
Background Previous studies have been unable to characterise the association between physical activity and obesity, possibly because most relied on inaccurate measures of obesity. Methods Findings We carried out a cross sectional analysis 5,500 12-year-old children enrolled in Avon Longitudinal Study Parents Children. Total minutes moderate vigorous (MVPA) were measured using Actigraph accelerometer. Fat mass obesity (defined as top decile fat mass) Lunar Prodigy dual x-ray emission...
Abstract The frequency of, and risk factors for, long COVID are unclear among community-based individuals with a history of COVID-19. To elucidate the burden possible causes in community, we coordinated analyses survey data from 6907 self-reported COVID-19 10 UK longitudinal study (LS) samples 1.1 million diagnostic codes electronic healthcare records (EHR) collected by spring 2021. Proportions presumed cases LS reporting any symptoms for 12+ weeks ranged 7.8% 17% (with 1.2 to 4.8%...
BackgroundSuicidal thoughts and non-suicidal self-harm are common in adolescents strongly associated with suicide attempts. We aimed to identify predictors of future attempts these high-risk groups.MethodsParticipants were from the Avon Longitudinal Study Parents Children, a population-based birth cohort study UK. The sample included 456 who reported suicidal 569 at 16 years age. Logistic regression analyses used explore associations between wide range prospectively recorded risk factors...
Background: Objective methods can improve accuracy of physical activity measurement in field studies but uncertainties remain about their use. Methods: Children age 11 years from the Avon Longitudinal Study Parents and (ALSPAC), were asked to wear a uni-axial accelerometer (MTI Actigraph) for 7 days. Results: Of 7159 children who attended assessment, 5595 (78%) provided valid measures. The reliability coefficient 3 days recording was .7 power detect difference 0.07 SDs ( P ≤ .05) > 90%....
Multiple imputation is increasingly recommended in epidemiology to adjust for the bias and loss of information that may occur analyses restricted study participants with complete data ("complete-case analyses"). However, little guidance available on applying method, including which variables include model number imputations needed. Here, authors used multiple analyze prevalence wheeze among 81-month-old children Avon Longitudinal Study Parents Children (Avon, United Kingdom; 1991-1999)...
Maternal smoking during pregnancy has been found to influence newborn DNA methylation in genes involved fundamental developmental processes. It is pertinent understand the degree which offspring methylome sensitive intensity and duration of prenatal smoking. An investigation persistence associated with maternal relative roles intrauterine postnatal environment also warranted. In Avon Longitudinal Study Parents Children, we investigated associations between exposure at multiple time points...
<b>Objectives</b> To examine the prospective associations between body mass index (BMI), waist circumference, and fat in childhood cardiovascular risk factors at age 15-16. <b>Design</b> Prospective cohort study. <b>Setting</b> Avon Longitudinal Study of Parents Children. <b>Participants</b> 5235 children aged 9-12 start <b>Main exposures </b>BMI, determined by dual energy x ray absorptiometry, assessed outcome measures</b> Systolic diastolic blood pressure concentrations fasting glucose,...
Teachers have been shown to high levels of stress and common mental disorder, but few studies examined which factors within the school environment are associated with poor teacher health.Teachers (n=555) in 8 schools completed self-report questionnaires. Levels wellbeing (Warwick Edinburgh Mental Wellbeing Scale-WEMWBS) depressive symptoms (Patient Health Questionnaire-PHQ-9) were measured associations between these measures school-related using multilevel multivariable regression models.The...
Background: Although cohort members tend to be healthy and affluent compared with the whole population, some studies indicate this does not bias certain exposure-outcome associations. It is less clear whether holds when socioeconomic position (SEP) exposure of interest. Methods: As an illustrative example, we use data from Avon Longitudinal Study Parents Children. We calculate estimates maternal education inequalities in outcomes for which are available on almost (birth weight length,...