03rd Feb 2019
Objective: Attending childcare is related to greater childhood obesity risk, but there are few long-term follow-up studies. We aimed to examine the associations of childcare type, duration, and intensity with BMI trajectories from ages 10-42 years.
Research Design and Methods: The sample comprised 8234 individuals in the 1970 British Cohort Study, who had data on childcare attendance (no, yes), type (formal, informal), duration (4-5, 3-3.99, 0-2.99 years old when started), and intensity (1, 2, 3, 4-5 days/week) reported at age five years and 32563 BMI observations. Multilevel linear spline models were used to estimate the association of each exposure with the sample-average BMI trajectory, with adjustment for sex, father’s occupational class, and mother’s age of leaving full time education. A combined duration and intensity exposure was also examined.
Results: Childcare attendance and type were not strongly related to BMI trajectories. Results for the combined exposure revealed additive effects of childcare duration and intensity. Among participants who attended childcare 1-2 days a week, those who started when 3-3.99 years old had a 0.197 (-0.004, 0.399) kg/m2 higher BMI at age 10 years than those who started when 4-5 years old, and those who started when 0-2.99 years old had a 0.289 (0.049, 0.529) kg/m2 higher BMI. A similar dose-response pattern for intensity was observed when holding duration constant.