Are observed associations between a high maternal prepregnancy body mass index and offspring IQ likely to be causal?
- 29 July 2019
- journal article
- research article
- Published by BMJ in Journal of Epidemiology and Community Health
- Vol. 73 (10), 920-928
- https://doi.org/10.1136/jech-2019-212257
Abstract
Background A high maternal prepregnancy body mass index has been associated with lower offspring IQ, but it is unclear if the relationship is causal. To explore this, our objectives were to compare maternal and paternal estimates and to assess whether certain factors mediate the association. Methods We analysed data from the Avon Longitudinal Study of Parents and Children, which initially recruited 14 541 women residing in Avon, UK, with an expected date of delivery in 1991–1992. Data were collected during and after pregnancy by questionnaire, medical record abstraction and clinical assessment. At approximately 8 years of age, psychologists administered an abbreviated form of the Wechsler Intelligence Scale for Children-III. We fit multivariable logistic regression models to estimate parental prepregnancy obesity and overweight–offspring IQ associations. Counterfactually defined indirect (mediated) effects of maternal prepregnancy obesity on offspring IQ were estimated through path analysis. Results Among 4324 mother–father–child triads and using normal weight as the referent, we observed consistently stronger associations for maternal prepregnancy obesity and offspring performance IQ (eg, adjusted β (95% CI)=−3.4 (−5.7 to −1.2) vs −0.97 (−2.9 to 0.96) for paternal obesity). The indirect effects of maternal obesity on offspring IQ through pathways involving gestational weight gain and duration of breastfeeding were small but significant. Conclusion Our findings are consistent with a weak biologic effect of maternal adiposity in pregnancy on offspring performance IQ. Given the growing prevalence of obesity worldwide, more evidence is needed to resolve the correlation versus causation debate in this area.Keywords
Funding Information
- Queen’s University Department of Pediatrics Development and Innovation Fund (N/A)
This publication has 40 references indexed in Scilit:
- On the Interpretation and Use of Mediation: Multiple Perspectives on Mediation AnalysisFrontiers in Psychology, 2017
- Association between pre-pregnancy overweight and obesity and children’s neurocognitive development: a systematic review and meta-analysis of observational studiesInternational Journal of Epidemiology, 2017
- Effect of parental obesity and gestational diabetes on child neuropsychological and behavioral development at 4 years of age: the Rhea mother–child cohort, Crete, GreeceEuropean Child & Adolescent Psychiatry, 2017
- Influence of maternal obesity on the long-term health of off springThe Lancet Diabetes & Endocrinology, 2016
- Developmental origins of health and diseaseCurrent Opinion in Pediatrics, 2015
- Approaches for drawing causal inferences from epidemiological birth cohorts: A reviewEarly Human Development, 2014
- Maternal prepregnancy obesity and child neurodevelopment in the Collaborative Perinatal ProjectInternational Journal of Epidemiology, 2014
- Maternal Pre-Pregnancy BMI and Intelligence Quotient (IQ) in 5-Year-Old Children: A Cohort Based StudyPLOS ONE, 2014
- Maternal pre-pregnancy overweight and obesity, and child neuropsychological development: two Southern European birth cohort studiesInternational Journal of Epidemiology, 2013
- Intrauterine Effects of Maternal Prepregnancy Overweight on Child Cognition and Behavior in 2 CohortsPEDIATRICS, 2011