scholarly journals Prenatal exposure to maternal smoking and offspring DNA methylation across the lifecourse: findings from the Avon Longitudinal Study of Parents and Children (ALSPAC)

2014 ◽  
Vol 24 (8) ◽  
pp. 2201-2217 ◽  
Author(s):  
Rebecca C. Richmond ◽  
Andrew J. Simpkin ◽  
Geoff Woodward ◽  
Tom R. Gaunt ◽  
Oliver Lyttleton ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Longitudinal Study ◽  
Prenatal Exposure ◽  
Maternal Smoking ◽  
Parents And Children ◽  
Avon Longitudinal Study

scholarly journals Association between Breastfeeding and DNA Methylation over the Life Course: Findings from the Avon Longitudinal Study of Parents and Children (ALSPAC)

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3309 ◽  
Author(s):  
Fernando Pires Hartwig ◽  
George Davey Smith ◽  
Andrew J. Simpkin ◽  
Cesar Gomes Victora ◽  
Caroline L. Relton ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Longitudinal Study ◽  
Negative Control ◽  
Childhood And Adolescence ◽  
Long Term Effects ◽  
Parents And Children ◽  
Short And Long Term ◽  
The Life Course ◽  
Avon Longitudinal Study

Background: Breastfeeding is associated with short and long-term health benefits. Long-term effects might be mediated by epigenetic mechanisms, yet the literature on this topic is scarce. We performed the first epigenome-wide association study of infant feeding, comparing breastfed vs non-breastfed children. We measured DNA methylation in children from peripheral blood collected in childhood (age 7 years, N = 640) and adolescence (age 15–17 years, N = 709) within the Accessible Resource for Integrated Epigenomic Studies (ARIES) project, part of the larger Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Cord blood methylation (N = 702) was used as a negative control for potential pre-natal residual confounding. Results: Two differentially-methylated sites presented directionally-consistent associations with breastfeeding at ages 7 and 15–17 years, but not at birth. Twelve differentially-methylated regions in relation to breastfeeding were identified, and for three of them there was evidence of directional concordance between ages 7 and 15–17 years, but not between birth and age 7 years. Conclusions: Our findings indicate that DNA methylation in childhood and adolescence may be predicted by breastfeeding, but further studies with sufficiently large samples for replication are required to identify robust associations.

scholarly journals Association between breastfeeding and DNA methylation over the life course: findings from the Avon Longitudinal Study of Parents and Children (ALSPAC)

2019 ◽  
Author(s):  
Fernando Pires Hartwig ◽  
George Davey Smith ◽  
Andrew J Simpkin ◽  
Cesar Gomes Victora ◽  
Caroline L. Relton ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Longitudinal Study ◽  
Negative Control ◽  
Childhood And Adolescence ◽  
Long Term Effects ◽  
Parents And Children ◽  
Short And Long Term ◽  
The Life Course ◽  
Avon Longitudinal Study

AbstractBackgroundBreastfeeding is associated with short and long-term health benefits. Long-term effects might be mediated by epigenetic mechanisms, yet a recent systematic review indicated that the literature on this topic is scarce. We performed the first epigenome-wide association study of infant feeding, comparing breastfed vs non-breastfed children. We measured DNA methylation in children from peripheral blood collected in childhood (age 7, N=640) and adolescence (age 15-17, N=709) within the Accessible Resource for Integrated Epigenomic Studies (ARIES) project, part of the larger Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Cord blood methylation (N=702) was used as a negative control for potential pre-natal residual confounding.ResultsTwo differentially-methylated sites presented directionally-consistent associations with breastfeeding at ages 7 and 15-17, but not at birth. Twelve differentially-methylated regions in relation to breastfeeding were identified, and for three of them there was evidence of directional concordance between ages 7 and 15-17, but not between birth and age 7.ConclusionsOur findings indicate that DNA methylation in childhood and adolescence may be predicted by breastfeeding, but further studies with sufficiently large samples for replication are required to identify robust associations.

scholarly journals Factors associated with participation over time in the Avon Longitudinal Study of Parents and Children: a study using linked education and primary care data

2020 ◽  
Author(s):  
RP Cornish ◽  
J Macleod ◽  
A Boyd ◽  
K Tilling
Keyword(s):  
Primary Care ◽  
Longitudinal Study ◽  
Maternal Smoking ◽  
Demographic Factors ◽  
Routine Data ◽  
Primary Care Data ◽  
Parents And Children ◽  
Baseline Factors ◽  
Socio Demographic Factors ◽  
Avon Longitudinal Study

AbstractBackgroundDropout from studies can lead to biased exposure-outcome estimates if the outcome is associated with continued participation, but this cannot be investigated using incomplete data. Linkage to external datasets provides a means of obtaining outcome – or proxy outcome - data on non-responders.MethodsWe examined the association between baseline socio-demographic factors and participation in the Avon Longitudinal Study of Parents and Children. We investigated whether child and adolescent outcomes measured in linked education and primary care data were associated with participation after accounting for baseline factors. To demonstrate the potential for bias, we examined whether the association between maternal smoking and these outcomes differed in the subsample who completed the 19-year questionnaire.ResultsLower levels of school attainment, lower GP consultation and prescription rates, higher BMI, special educational needs (SEN) status, not having an asthma diagnosis, depression and being a smoker were all associated with lower participation after adjustment for baseline factors. For example, adjusted odds ratio (OR) for participation comparing ever smokers (by 18 years) to non-smokers: 0.65, 95% CI (0.56, 0.75). The association of maternal smoking differed between the subsample of participants at 19 years and the entire sample, although differences were small and confidence intervals overlapped. For example: for SEN status OR=1.19 (1.06, 1.33) (all participants); OR=1.03 (0.79, 1.45) (subsample).ConclusionsLinkage to routine data provides a unique opportunity to compare continuing participators to those who drop out, and the impact this self-selection can have on results. Cohort studies should use linkage to routine data to explore participation and conduct sensitivity analyses.Key messagesEducational and health-related characteristics are strongly associated with ongoing participation in the Avon Longitudinal Study of Parents and Children after adjustment for detailed socio-demographic factors.This could bias analyses using the dataset, with bias dependent on the variables used in the analysis and their impact on participation.Linkage to routine data provides a means of assessing whether factors measured across the life course are associated with ongoing participation in observational studies and the potential impact of this in terms of bias.Researchers can use linkage to external sources of data to make informed decisions about the likely impact of selective participation and to guide their analyses.

scholarly journals Factors associated with participation over time in the Avon Longitudinal Study of Parents and Children: a study using linked education and primary care data

2020 ◽  
Author(s):  
Rosie P Cornish ◽  
John Macleod ◽  
Andy Boyd ◽  
Kate Tilling
Keyword(s):  
Primary Care ◽  
Longitudinal Study ◽  
Cohort Studies ◽  
Incomplete Data ◽  
Maternal Smoking ◽  
Factors Associated ◽  
Primary Care Data ◽  
Parents And Children ◽  
Baseline Factors ◽  
Avon Longitudinal Study

Abstract Background In observational research, choosing an optimal analysis strategy when variables are incomplete requires an understanding of the factors associated with ongoing participation and non-response, but this cannot be fully examined with incomplete data. Linkage to external datasets provides additional information on those with incomplete data, allowing examination of factors related to missingness. Methods We examined the association between baseline sociodemographic factors and ongoing participation in the Avon Longitudinal Study of Parents and Children. We investigated whether child and adolescent outcomes measured in linked education and primary care data were associated with participation, after accounting for baseline factors. To demonstrate the potential for bias, we examined whether the association between maternal smoking and these outcomes differed in the subsample who completed the 19-year questionnaire. Results Lower levels of school attainment, lower general practitioner (GP) consultation and prescription rates, higher body mass index (BMI), special educational needs (SEN) status, not having an asthma diagnosis, depression and being a smoker were associated with lower participation after adjustment for baseline factors. For example, the adjusted odds ratio (OR) for participation comparing ever smokers (by 18 years) with non-smokers was: 0.65, 95% CI (0.56, 0.75). The associations with maternal smoking differed between the subsample of participants at 19 years and the entire sample, although differences were small and confidence intervals overlapped. For example: for SEN status, OR = 1.19 (1.06, 1.33) (all participants); OR = 1.03 (0.79, 1.45) (subsample). Conclusions A range of health-related and educational factors are associated with ongoing participation in ALSPAC; this is likely to be the case in other cohort studies. Researchers need to be aware of this when planning their analysis. Cohort studies can use linkage to routine data to explore predictors of ongoing participation and conduct sensitivity analyses to assess potential bias.

scholarly journals Trimester effects of source-specific PM10 on birth weight outcomes in the Avon Longitudinal Study of Parents and Children (ALSPAC)

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Yingxin Chen ◽  
Susan Hodgson ◽  
John Gulliver ◽  
Raquel Granell ◽  
A. John Henderson ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Birth Weight ◽  
Regression Models ◽  
Linear Regression Models ◽  
Exposure Misclassification ◽  
Third Trimester ◽  
Residential History ◽  
The Third ◽  
Parents And Children ◽  
Avon Longitudinal Study

Abstract Background Evidence suggests that exposure to particulate matter with aerodynamic diameter less than 10 μm (PM10) is associated with reduced birth weight, but information is limited on the sources of PM10 and exposure misclassification from assigning exposures to place of residence at birth. Methods Trimester and source-specific PM10 exposures (PM10 from road source, local non-road source, and total source) in pregnancy were estimated using dispersion models and a full maternal residential history for 12,020 births from the Avon longitudinal study of parents and children (ALSPAC) cohort in 1990–1992 in the Bristol area. Information on birth outcomes were obtained from birth records. Maternal sociodemographic and lifestyle factors were obtained from questionnaires. We used linear regression models for continuous outcomes (birth weight, head circumference (HC), and birth length (BL) and logistic regression models for binary outcomes (preterm birth (PTB), term low birth weight (TLBW) and small for gestational age (SGA)). Sensitivity analysis was performed using multiple imputation for missing covariate data. Results After adjustment, interquartile range increases in source specific PM10 from traffic were associated with 17 to 18% increased odds of TLBW in all pregnancy periods. We also found odds of TLBW increased by 40% (OR: 1.40, 95%CI: 1.12, 1.75) and odds of SGA increased by 18% (OR: 1.18, 95%CI: 1.05, 1.32) per IQR (6.54 μg/m3) increase of total PM10 exposure in the third trimester. Conclusion This study adds to evidence that maternal PM10 exposures affect birth weight, with particular concern in relation to exposures to PM10 from road transport sources; results for total PM10 suggest greatest effect in the third trimester. Effect size estimates relate to exposures in the 1990s and are higher than those for recent studies – this may relate to reduced exposure misclassification through use of full residential history information, changes in air pollution toxicity over time and/or residual confounding.

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