OBJECTIVE
To examine the extent to which infant sleep duration is associated with overweight at age 3 years.
DESIGN
Longitudinal survey.
SETTING
Multisite group practice in Massachusetts.
PARTICIPANTS
Nine hundred fifteen children in Project Viva, a prospective cohort. Main Exposure At children's ages 6 months, 1 year, and 2 years, mothers reported the number of hours their children slept in a 24-hour period, from which we calculated a weighted average of daily sleep.
MAIN OUTCOME MEASURES
We used multivariate regression analyses to predict the independent effects of sleep duration (< 12 h/d vs > or = 12 h/d) on body mass index (BMI) (calculated as the weight in kilograms divided by the height in meters squared) z score, the sum of subscapular and triceps skinfold thicknesses, and overweight (BMI for age and sex > or = 95th percentile) at age 3 years.
RESULTS
The children's mean (SD) duration of daily sleep was 12.3 (1.1) hours. At age 3 years, 83 children (9%) were overweight; the mean (SD) BMI z score and sum of subscapular and triceps skinfold thicknesses were 0.44 (1.03) and 16.66 (4.06) mm, respectively. After adjusting for maternal education, income, prepregnancy BMI, marital status, smoking history, and breastfeeding duration and child's race/ethnicity, birth weight, 6-month weight-for-length z score, daily television viewing, and daily participation in active play, we found that infant sleep of less than 12 h/d was associated with a higher BMI z score (beta, 0.16; 95% confidence interval, 0.02-0.29), higher sum of subscapular and triceps skinfold thicknesses (beta, 0.79 mm; 95% confidence interval, 0.18-1.40), and increased odds of overweight (odds ratio, 2.04; 95% confidence interval, 1.07-3.91).
CONCLUSION
Daily sleep duration of less than 12 hours during infancy appears to be a risk factor for overweight and adiposity in preschool-aged children.