Self-Reported Long Total Sleep Duration Is Associated With Metabolic Syndrome: The Guangzhou Biobank Cohort Study

OBJECTIVE: To examine the association between total sleep duration and the prevalence of metabolic syndrome (MetSyn) in older Chinese. RESEARCH DESIGN AND METHODS: Cross-sectional analysis of baseline data from the Guangzhou Biobank Cohort Study (GBCS) was performed. Participants (n = 29,333) were aged ≥50 years. Risk of MetSyn and its components were identified for self-reported total sleep duration. RESULTS: Participants reporting long (≥9 h) and short (<6 h) total sleep duration had increased odds ratio (OR) of 1.18 (95% CI 1.07–1.30) and 1.14 (1.05–1.24) for the presence of MetSyn, respectively. The relationship remained in long sleepers (OR 1.21 [1.10–1.34]) but diminished in short sleepers (0.97 [0.88–1.06]) after full adjustment. CONCLUSIONS: Long sleep duration was associated with greater risk of MetSyn in older Chinese. Confirmation through longitudinal studies is needed. The mechanisms mediating the link between long sleep duration and MetSyn require further investigation.