Childhood Sleep Time and Long-Term Risk for Obesity: A 32-Year Prospective Birth Cohort Study

OBJECTIVE: Associations between short sleep duration and increased BMI have been found in children and adults. However, it is not known whether short sleep time during childhood has long-term consequences. We assessed the association between sleep time in childhood and adult BMI in a birth cohort. METHODS: Study members were a general-population birth cohort of 1037 participants (502 female) who were born in Dunedin, New Zealand, between April 1972 and March 1973. Parental reports of bedtimes and rising times collected at ages 5, 7, 9, and 11 years were used to estimate childhood sleep time. Linear regression analysis was used to analyze the association between childhood sleep time and BMI measured at 32 years of age. RESULTS: Shorter childhood sleep times were significantly associated with higher adult BMI values. This association remained after adjustment for adult sleep time and the potential confounding effects of early childhood BMI, childhood socioeconomic status, parental BMIs, child and adult television viewing, adult physical activity, and adult smoking. In logistic regression analyses, more sleep time during childhood was associated with lower odds of obesity at 32 years of age. This association was significant after adjustment for multiple potential confounding factors. CONCLUSIONS: These findings suggest that sleep restriction in childhood increases the long-term risk for obesity. Ensuring that children get adequate sleep may be a useful strategy for stemming the current obesity epidemic.