Relationship between sleep duration and Framingham cardiovascular risk score and prevalence of cardiovascular disease in Koreans

Studies have shown sleep duration to be related to the prevalence of metabolic syndrome and hypertension. However, whether sleep duration is associated with cardiovascular disease (CVD) risk and the prevalence of CVD irrespective of conventional CV-risk factor, such as diabetes mellitus, obesity, and metabolic syndrome, has not been well established for the Korean population. A total of 23,878 individuals aged 18 years or older from the 2007-2010 Korean National Health and Nutrition Examination Survey were analyzed. We evaluated the relationship between sleep duration and CV-event risk using the Framingham Cardiovascular Risk Score (FRS; >= 10% or >= 20%) and the prevalence of CVD. After adjusting for traditional risk factors of CVD, a short sleep duration (<= 5hours) yielded odds ratios (OR) of 1.344 (95% confidence interval [CI] 1.200-1.505) for intermediate to high risk and 1.357 (95% CI, 1.140-1.614) for high risk. A long sleep duration (>= 9hours) was also associated with both intermediate to high (OR 1.142, 95% CI 1.011-1.322) and high cardiovascular FRS (OR 1.276, 95% CI 1.118-1.457). Both short and long sleep durations were related with high CVD risk, irrespective of established CVD risk, and a short sleep duration was associated with a higher prevalence of CVD than an optimal or long sleep duration.