A US cross-sectional and prospective analysis suggested that increased variability in sleep duration and timing was associated with higher prevalence and incidence of metabolic abnormalities even after considering sleep duration and other lifestyle factors. Participants completed 7-day actigraphy from 2010 to 2013 and were prospectively followed throughout 2016 to 2017. Sleep regularity was quantified by the 7-day SD of actigraphy-assessed sleep duration and sleep onset timing. In the cross-sectional analysis adjusted for sociodemographic and lifestyle factors (n = 2,003), every 1-h increase in the sleep duration SD was associated with 27% higher odds of metabolic syndrome, and every 1-h increase in the sleep timing SD was associated with 23% higher odds. The associations remained significant, with additional adjustment for sleep-related factors including sleep duration. In the prospective analysis (n = 970), the corresponding fully adjusted odds ratio (OR) was 1.27 for sleep duration and 1.36 for sleep timing. Compared with the cluster of few metabolic changes, every 1-h increase in sleep variability was associated with almost doubled odds for the cluster characterized by incidence of multiple metabolic abnormalities (OR 1.97 for sleep duration and OR 2.10 for sleep timing). Source: http://care.diabetesjournals.org/
