OBJECTIVE: We investigated associations of sleep duration and social jetlag with cardiometabolic outcomes.
PARTICIPANTS: Boys and girls aged 8-16 years from the Hispanic Community Health Study/Study of Latino Youth.
MEASUREMENTS: Participants (n = 1,208) completed a clinical examination where anthropometric characteristics, health behaviors, and health history were measured. Sleep duration was calculated as the weighted average of self-reported weekday and weekend bedtimes and wake times and categorized into age-specific cutoffs for short vs. normal sleep. "Social jetlag" was defined as the absolute difference in the midpoint of the sleep period between weekdays and weekends, measured continuously and dichotomized (≥2 hours), with higher values indicating more displacement of sleep timing across the week. Regression models tested the associations between sleep measures (separately) and cardiometabolic outcomes (e.g., healthy eating index [0-100], physical activity-minutes per week, obesity, diabetes, hypertension) after adjustment for covariates.
RESULTS: The average sleep duration was 9.5 hours (95% confidence interval: 9.3, 9.6) and the mean social jetlag was 2.5 (2.4, 2.7) hours. Participants with social jetlag reported more physical activity (β = 34.8 [13.14], P < .01), had a higher healthy eating index (β = 1.77 [0.87], P < .05] and lower odds of being overweight [OR = 0.66, (95% confidence interval 0.44, 0.99)]. Short sleep duration was associated with less physical activity but did not relate to other cardiometabolic outcomes.
CONCLUSIONS: Social jetlag was associated with healthier behaviors and a lower odds of being overweight. Given these mixed findings, future research should further evaluate how to best characterize sleep timing differences in youth to identify health consequences.
