Abstract
BACKGROUND: One in three children are living with overweight or obesity in North America. The burden of childhood obesity is disproportionately experienced by children from low-income families, who are more likely to have obesity. Centre-based child care attendance may influence important adiposity risk factors such as dietary intake, eating behaviour, and physical activity, but its impact on childhood obesity is unclear. OBJECTIVES: The primary objective was to evaluate the relationship between the intensity of centre-based child care attendance between 1 and 4 years of age and Body Mass Index z-score (zBMI) from 4 to 10 years of age relative to non-centre-based child care (i.e., home-based, grandparents, relatives, and nanny’s). The secondary objective was to explore if family income modified the relationship. DESIGN/METHODS: A prospective cohort study of children 1 to 10 years of age was conducted through the TARGet Kids! primary care research network. The primary exposure was intensity of centre-based child care attendance (hours/week). The primary outcome was zBMI, an age and sex adjusted measure of child adiposity. Interaction terms for child age and family income were explored. A linear mixed effects model and logistic generalized estimating equations were used to determine the association between centre-based child care attendance and child zBMI. RESULTS: 3,503 children were included (mean age: 2.7 years). Children who attended centre-based child care full time (40 hours/week) had a 0.11 lower zBMI at 4 years (95% CI -0.19, -0.03; p=0.005) and lower odds of obesity (zBMI > 2) at 4 (OR 0.58; 95% CI 0.34, 0.99; p=0.04) and 10 years of age (OR 0.52; 95% CI 0.29, 0.90; p=0.02) relative to children who attended non-centre-based child care. The relationship was modified by family income such that, children from families with an income of <$50,000CDN who attended centre-based child care full time had a 0.35 (95% CI -0.56, -0.15; p=0.001), 0.34 (95% CI -0.54, -0.13, p=0.001) and 0.29 (95% CI -0.50, -0.07, p=0.009) lower zBMI at 4, 7 and 10 years of age, respectively, relative to children who attended non-centre-based child care. CONCLUSION: Centre-based child care attendance in early childhood was associated with lower adiposity and odds of obesity in later childhood. This relationship was stronger for children who were from lower income families. Centre-based child care may be an effective early intervention to prevent childhood obesity.