Optimal cutoffs of sleep timing and sleep duration for cardiovascular risk factors.

• Although many studies have used sleep-related variables, there is no clear evidence on cutoffs of sleep-related variables. • In this study, the cutoff was obtained through the receiver operating characteristic analysis of sleep-related variables. • The optimal cutoff to discriminate cardiovascular disease risk factors was 10:00 PM to 11:00 PM for bedtime. • The optimal cutoff to discriminate cardiovascular disease risk factors was 12:00 AM to 3:00 AM for mid-sleep time. • The optimal cutoff to discriminate cardiovascular disease risk factors was around 6 h for sleep duration. We aimed to establish the optimal cutoffs of sleep timing and duration to assess obesity, hypertension (HTN), diabetes mellitus (DM), dyslipidemia (DL), and metabolic syndrome (MetS) using data from the Korea National Health and Nutrition Examination Surveys. In this cross-sectional study, data from 18,677 participants (8,107 men and 10,570 women) aged 19 or over were used. A receiver operating characteristic (ROC) curve adjusted for potential confounding variables was constructed to calculate the cutoff of sleep-related variables (bedtime, mid-sleep on free days corrected for sleep debt on workdays (MSFsc), and sleep duration) for assessing cardiovascular disease (CVD) risk factors according to sex. Bedtime between 9:00 PM to 0:30 AM for men and 10:00 PM to 11:00 PM for women is appropriate for assessing obesity, HTN, DM, DL, and MetS. The cutoff range was 9:00 PM to 11:00 PM for men ≥65 years and 9:00 PM to 12:00 AM for women ≥65 years, which was slightly earlier than that for participants <65 years. The optimal MSFsc cutoff points were established between 12:00 AM to 3:00 AM and sleep durations around 6 h were associated with the optimal cutoffs for assessing CVD risk factors. Bedtime between 10:00 PM to 11:00 PM, early MSFsc, and short sleep durations were appropriate for assessing CVD risk factors. [ABSTRACT FROM AUTHOR]