1.
Sleep duration modifies effects of free ad libitum school meals on adiposity and blood pressure.
Hjorth, MF, Sjödin, A, Dalskov, SM, Damsgaard, CT, Michaelsen, KF, Biltoft-Jensen, A, Andersen, R, Ritz, C, Chaput, JP, Astrup, A
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2016;(1):33-40
Abstract
Insufficient sleep can potentially affect both energy intake and energy expenditure, resulting in obesity and reduced cardiometabolic health. The objective of the study was to investigate if habitual sleep duration of 8- to 11-year-olds modifies the effect of free ad libitum school meals on cardiometabolic markers, body composition, dietary intake, and physical activity. For 2 consecutive 3-month periods, this cluster-randomized, controlled, cross-over trial provided 530 children with school meals or usual lunch brought from home. Dietary intake, activity, and sleep were measured simultaneously for 7 consecutive days using dietary records and accelerometers. Short- and long-sleeping children were defined as lower and upper tertile of sleep duration. Body composition, blood pressure, blood lipids, and homeostatic model assessment of insulin resistance (HOMAIR) were measured/calculated. Overall, school meals compared with lunch from home had positive effects on physical activity and blood pressure in long-sleeping children and negative effects on body fat in short-sleeping children. Short-sleeping children increased fat mass compared with long-sleeping children by 0.21 (95% confidence interval 0.03-0.38) kg, android fat mass by 0.02 (0.001-0.04) kg, waist circumference by 0.73 (0.23-1.24) cm, blood pressure by 1.5 (0.4-2.6) mm Hg, fat intake by 1.1 (0.2-2.0) percentage of energy, and decreased total physical activity by 7.2 (1.6-12.7) % (all P ≤ 0.04), while HOMAIR and blood lipids were not modified by sleep duration (all P ≥ 0.32). In conclusion, the susceptibility to increase abdominal adiposity and blood pressure when exposed to dietary changes can potentially be explained by too little sleep, which results in increased caloric intake and reduced physical activity.
2.
Physical Activity, Sedentary Time, and Sleep and the Association With Inflammatory Markers and Adiponectin in 8- to 11-Year-Old Danish Children.
Nielsen, MS, Quist, JS, Chaput, JP, Dalskov, SM, Damsgaard, CT, Ritz, C, Astrup, A, Michaelsen, KF, Sjödin, A, Hjorth, MF
Journal of physical activity & health. 2016;(6):733-9
Abstract
BACKGROUND Inflammatory markers, adiponectin, and movement/nonmovement behaviors have all been linked to risk factors for cardiovascular disease; however, the association between childhood movement/nonmovement behaviors and inflammatory markers and adiponectin is unknown. METHODS We explored the association between accelerometer determined moderate-to-vigorous physical activity (MVPA), sedentary time, and sleep (7 days/8 nights) and fasting C-reactive protein (CRP), interleukin-6 (IL-6), and adiponectin in 806 school children. A sleep variability score was calculated. RESULTS MVPA was negatively associated with adiponectin in boys and girls (P < .001) and with CRP and IL-6 in girls (P < .05) independent of sleep duration, sedentary time, age, fat mass index (FMI), and pubertal status. Sedentary time was positively associated with adiponectin in boys and girls (both P < .001), and sleep duration with adiponectin in boys independent of age, FMI, and pubertal status (P < .001); however, these associations disappeared after mutual adjustments for movement behavior. Sleep duration variability was positively associated with CRP in girls independent of all covariates (P < .01). CONCLUSION MVPA remained negatively associated with inflammatory markers and adiponectin, and sleep duration variability positively associated with CRP after adjustment for FMI, pubertal status, and other movement behavior. The inverse association between MVPA and adiponectin conflicts with the anti-inflammatory properties of adiponectin.