Association of sleep duration at 1.5 years with overweight/obesity at 3 years and effect modification by allergic conditions: The Japan Environment and Children's Study.

BACKGROUND

Evidence on associations of short sleep duration with obesity is limited and conflicting in toddlers. Additionally, the role of allergic conditions in this association remains elusive although the allergic conditions are known to affect both sleep quality and the development of obesity.

METHODS

In the current study, we investigated these associations using the Japan Environment and Children's Study, a nationwide prospective birth cohort. Data from 52,047 term-singleton births born with appropriate-for-gestational age without background disorders were included. Self-administered questionnaires evaluated sleep durations at 1.5 years old completed by caregivers. Overweight/obesity was defined as body mass index (BMI) at or above the 85th percentile at 3 years old.

RESULTS

After adjustment for sex, age, mother's BMI, socioeconomic status, and allergic conditions (asthma, food allergy, and atopic dermatitis), the multivariate odds ratio (95% confidence interval) for overweight/obesity at 3 years old were 0.97 (0.91-1.05), 1.03 (0.96-1.10), and 1.09 (1.00-1.19) for 10.5 or 11 h, 9.5 or 10 h, and ≤ 9 h of nighttime sleep duration, respectively, compared with those with ≥ 11.5 h (p for trend = 0.002). Similar associations were observed for total sleep duration. Food allergy modified the association between nighttime sleep duration and overweight/obesity (p for interaction = 0.02), whereas asthma and atopic dermatitis did not.

CONCLUSIONS

Our study revealed the associations between short sleep duration and overweight/obesity and its effect modification by food allergy.