Association between Sleep Time and Blood Pressure in Korean Adolescents: Cross-Sectional Analysis of KNHANES VII

Background: Hypertension is highly related to sleep, and there have been a number of studies on sleep deprivation and the occurrence of hypertension. However, there is still insufficient research on the relationship between hypertension and various factors related to sleep. Thus, this study attempted to investigate the relationship between hypertension and sleep time-related variables in Korean adolescents. Methods: A total of 1470 adolescents (709 girls and 761 boys) between 12 and 18 years of age were enrolled through the Seventh Korea National Health and Nutrition Examination Survey (KNHANES VII). The systolic and diastolic blood pressure were measured. Sleep time-related variables such as sleep onset time, wake time, and sleep duration (weekday and weekend, each) were also investigated using a questionnaire. We performed multivariate regression analyses to determine the independent effects of the variables. Results: Systolic blood pressure was negatively correlated with the wake time (r = -0.081; p = 0.002) and sleep onset time (r = -0.088; p = 0.001) on weekends. There was a positive correlation between diastolic blood pressure and weekday sleep onset time (r = 0.158; p = 0.000) and weekend sleep onset time (r = 0.184; p = 0.000). The sleep duration on weekdays and weekends showed a negative correlation (r = -0.136; p = 0.000, r = -0.088; p = 0.001, respectively). In the multivariate linear regression analysis results, the sleep onset time on weekends was significantly correlated with elevated diastolic blood pressure. Conclusions: Delayed sleep onset time on weekends was significantly associated with increased diastolic blood pressure in Korean adolescents. Further investigation is needed to confirm the clinical significance of these findings.