Sleep duration and blood pressure: a longitudinal analysis from early to late adolescence.
The aim of this study was to evaluate the association between sleep duration and blood pressure using a cross-sectional and longitudinal approach. As part of a population-based cohort, 1403 adolescents were evaluated at 13 and 17 years old. Sleep duration was estimated by the difference between self-reported usual bedtime and wake-up time. Blood pressure was measured using the auscultatory method. Regression coefficients (β) and respective 95% confidence intervals were computed to evaluate the association between sleep duration and blood pressure, using linear regression models adjusted for practice of sports and body mass index at 17 years old. The mean (standard deviation) sleep duration at 13 years old was 9.0 (0.76) h per day, and on average it decreased by 46 min up to 17 years old. The median (25th-75th) systolic blood pressure at 17 years old was 110.0 (103.5-119.0) mmHg in females and 114.0 (106.0-122.0)mmHg in males (P < 0.001); for diastolic blood pressure the values were 66.0 (60.0-71.0) and 69.0 (62.0-75.0) mmHg, respectively (P < 0.001). In cross-sectional analysis, at 17 years old, after adjustment, a positive association was found between sleep duration and blood pressure, significant only for systolic blood pressure among females [β = 0.730 (0.005; 1.455)]. In girls, no significant association was found between sleep duration at 13 years old and blood pressure at 17 years old, but in males an inverse association was found between sleep duration at 13 years old and blood pressure at 17 years old significant only for systolic blood pressure [β = -1.938 (-3.229; -0.647)]. This study found no association between sleep duration at 13 years old and blood pressure at 17 years old in girls, but among males an inverse association was found.