Poor-quality sleep is associated with metabolic syndrome in Korean adults.

Sleep disorder and metabolic syndrome (MetS) are important health-related problems. Recently, sleep duration has decreased among Korean adults. In this study, we examined whether sleep quality is associated with MetS by analyzing 301 subjects, aged 20 years or over, without acute and severe illness who visited three primary care clinics. Sleep duration, sleep quality and the risk of sleep-related breathing disorder (SRBD) were assessed with a standardized sleeping-estimating instrument. MetS was defined according to the modified diagnostic criteria of the National Cholesterol Education Program Adult Treatment Panel-III using the Korean abdominal obesity definition. In the multiple logistic regression analysis, compared with the 7-hour sleep group, the adjusted odds ratios (ORs) of the ≤ 5- and ≥ 9-hour sleep groups for MetS were 4.89 and 5.98, respectively. Compared with the good-sleep quality and low-SRBD risk groups, the adjusted ORs of the poor-quality sleep and high-SRBD risk groups were 3.83 and 1.92, respectively (p < 0.05). In the ≤ 5- and ≥ 9-hour sleep groups, the prevalence of elevated triglyceride and high HOMA-IR was higher (p = 0.069). In the poor-quality sleep group, the prevalence of abdominal obesity, elevated triglyceride, low HDL cholesterol, high fasting insulin and high HOMA-IR were higher. In the high-SRBD risk group, the prevalence of abdominal obesity, obesity and elevated triglyceride were higher (p < 0.05). Overall, the ≤ 5- or ≥ 9-hour sleep duration, poor-quality sleep and high-SRBD risk are related with the high prevalence of MetS, perhaps through elevated insulin-resistance resulting from adiposity.