Is childcare associated with the risk of overweight and obesity in the early years? Findings from the UK Millennium Cohort Study

Background: A recent assessment of childcare in OECD (Organisation for Economic Co-operation and Development) countries highlighted the potential for childcare to widen inequalities. Although childcare offers a potential setting for obesity prevention, little research has analysed the association between childcare and overweight, particularly in different socio-economic groups. Objectives: Our primary objective was to explore the association between childcare and overweight (including obesity), both overall and by socio-economic background, in a contemporary UK cohort of children at age 3 years (N = 12 354). Our secondary objective was to explore infant feeding as a potential mediator between childcare in infancy and overweight at age 3 years. Results: After controlling for confounders, children who were cared for in informal childcare (75% grandparents) between the age of 9 months and 3 years were more likely to be overweight than those cared for only by a parent (adjusted risk ratio (aRR) = 1.15, 95% confidence interval (CI) 1.04-1.27), particularly if they were in full-time childcare (aRR = 1.34, 95% CI 1.15-1.57). When stratifying by socio-economic background, the increased risk of overweight in informal childcare (compared with parental care) was limited to children from more advantaged groups: those whose mother was from a managerial or professional background (aRR = 1.23, 95% CI 1.02-1.47), had a degree (RR = 1.43, 95% CI 1.13-1.83) or lived in a couple household (RR = 1.18, 95% CI 1.06-1.32). There was no association between formal childcare and overweight. Infant feeding did not mediate the association between childcare use in infancy and overweight at age 3 years. Conclusions: Children from more advantaged families who use informal childcare are at increased risk of overweight. The UK government's drive to support parents into paid employment should be accompanied by health-related information and support for both informal and formal carers. As the majority of informal carers were grandparents, the recent government announcement to provide grandparents with National Insurance credits for caring for grandchildren provides a potential opportunity for health promotion. International Journal of Obesity (2010) 34, 1160-1168; doi:10.1038/ijo.2010.15; published online 9 February 2010