Abstract
Introduction
Short sleep duration is associated with overweight and obesity. Less clear is how sleep regularity and physical activity interact with sleep duration in predicting overweight across adolescent stages. This study examined interactions between (1) sleep duration and regularity, and (2) sleep duration and physical activity on overweight in preadolescents (10–11 years), early (12–14), and middle (15–17 years) adolescents.
Methods
Using the National Survey of Children’s Health 2017–2018 dataset, we included youth with sleep, physical activity and overweight data available (n=25,875) in the analyses. Parents reported their children’s sleep duration, sleep regularity and physical activity (>60 min/day) frequency per week. High Body Mass Index (BMI, ≥85th percentile) for age and sex indicated overweight/obesity. Accounting for complex survey design and covariates (age, sex, race, poverty, and resilience), separate logistic regression models (STATA 16.0) estimated the associations in preadolescents, early and middle adolescents.
Results
Preadolescents had the highest odds of high BMI compared to other age groups (OR= 0.64 and 0.78, p<0.001). Every hour increase in sleep duration was associated with 4–18% decrease in the odds of having high BMI, with the highest magnitude shown in preadolescents (OR=0.82, p<0.001), followed by adolescents aged 12–14 (OR=0.89, p<0.001) and 15–17 years old (OR=0.96, p=0.04). For preadolescents, irregular sleep (OR=1.41, p<0.001) and physical activity (OR=0.83, p=0.03) modified the association between sleep duration and BMI. Specifically, the association was attenuated or even reversed among irregular sleepers (OR=1.09, p=0.27) compared with regular sleepers (OR=0.77, p<0.001). Preadolescents with regular physical activity (≥4 days/week) showed stronger associations (OR=0.74, p<0.001) between sleep duration and BMI than their counterparts (OR=0.89, p=0.01). Sleep regularity was not associated with BMI nor a modifier in other age groups. Although there was no interaction with sleep duration, regular physical activity was independently associated with decreased odds of having high BMI (OR=0.62, p<0.001) in early and middle adolescents.
Conclusion
The relationship between lifestyle factors (i.e., sleep duration and physical activity) and BMI varies by age groups. Sufficient sleep duration, regular bedtimes and physical activity represent resilience factors against overweight/obesity, especially in preadolescents who are at greater risk for high BMI.
Support (if any)
N/A
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