Association Between Sleep Time and Pro- and Anti-Inflammatory Biomarkers Is Mediated by Abdominal Obesity Among Adolescents

Objectives: Movement behaviors and abdominal obesity are associated with higher inflammatory biomarkers. However, the role of waist circumference as a mediating factor is still unknown. Thus, our aims were to (1) test the associations between 24-hour movement behavior variables (physical activity, sedentary behavior, and sleep), abdominal obesity, and pro- and antiinflammatory biomarkers; and (2) investigate whether abdominal obesity had a mediating effect between the investigated associations. Methods: This multicenter cross-sectional study included 3591 adolescents (aged 12-17 y) from 4 Brazilian cities. Waist circumference (in centimeters; at half the distance between the iliac crest and at the lower costal margin), 24-hour movement behaviors (validated questionnaire), high-sensitive C-reactive protein, and adiponectin (serum plasma) were evaluated. We used multiple mediation regression models (95% confidence interval) to determine if waist circumference mediated the association between 24-hour movement behaviors and pro- and anti-inflammatory biomarkers. Results: The results revealed that screen time and moderate to vigorous physical activity were not associated with pro- or anti-inflammatory biomarkers. However, sleep duration (in hours per day) was negatively associated with pro- (C-reactive protein, beta = -0.08; 95% confidence interval, -0.38 to -0.02) and anti- (adiponectin, beta = -0.31; 95% confidence interval, -2.13 to -0.12) inflammatory biomarkers. Our results also showed that waist circumference mediated the association between sleep duration and high-sensitive C-reactive protein (2.7%), and adiponectin (2.8%). Conclusion: Sleep duration was inversely associated with pro- and antiinflammatory biomarkers, and these relations were mediated by abdominal obesity. Therefore, adolescents having healthy sleep can have implications for reducing waist circumference and inflammatory indicators.