Sarcopenia, or loss of muscle mass, occurs with aging and results in frailty, disability, cardiovascular disease, and insulin resistance. Recently, researchers have asserted that sarcopenia is not an inevitable process, but is a modifiable condition. Adequate sleep duration is also important to maintain good physical and mental health. Therefore, the aim of our study was to examine the association between sleep duration and sarcopenia in Korean adults. Data from 16,148 participants (7,158 men and 8,990 women) were analyzed from the 2008-2011 Korean National Health and Nutrition Examination Survey (KNHANES). We defined sarcopenia as one standard deviation below the sex-specific means of the appendicular skeletal muscle/height-squared values of a young reference group. Participants were categorized into 5 groups according to sleep duration. The odds ratios (OR) and 95% confidence intervals (95% CI) for sarcopenia according to sleep duration were calculated using multiple logistic regression analysis. The prevalence of sarcopenia was 14.3% in the total population (males 18.7%, females 9.7%). Compared to the 7 hours of sleep group, the OR (95% CI) for sarcopenia of the long sleep duration group (9 hours or more) was 1.589 (1.100-2.295) after controlling for confounding factors. From the results of subgroup analysis, high-risk groups for sarcopenia are as follows: 40-64 years old (OR = 1.868), normal body mass index (OR = 1.516), smoking (OR = 2.219), no regular exercise (OR = 1.506) in long sleepers. Long sleep duration (9 hours or longer) is independently associated with sarcopenia in Korean adults.

The visceral adiposity index (VAI), an indirect marker of visceral adipose tissue, serves as a model associated with cardiometabolic risk, but has limitations regarding the Asian population. We sought to develop a new VAI (NVAI) for the Korean population and compare it to VAI for prediction of atherosclerotic cardiovascular disease (ASCVD) risk and development of major cardiovascular diseases (CVD) and stroke. Patients (969) who underwent visceral fat area measurement were analyzed. After exclusion, 539 patients (142 men, 397 women) were randomly divided into internal (n = 374) and external validation (n = 165) data set. The NVAI was developed using univariate and multivariate logistic regression with backward selection of predictors. Receiver operating characteristic (ROC) curve analysis and comparison of the area under the curve (AUC) verified the better predictor of ASCVD risk score. Additionally, nationwide population-based cross-sectional survey data (Korean National Health and Nutrition Examination Survey [KNHANES] 2008–2010, n = 29,235) was used to validate the NVAI’s ability to predict ASCVD risk and major CVD and stroke. The NVAI better reflected visceral fat area in internal and external data sets, with AUCs of 0.911 (95% confidence interval [CI]: 0.882–0.940) and 0.879 (95% CI: 0.828–0.931), respectively. NVAI better discriminated for ASCVD risk (AUC = 0.892, 95% CI: 0.846–0.938) compared to VAI (0.559, 95% CI: 0.439–0.679). The NVAI also better predicted MI or angina, and stroke with AUCs of 0.771 (95% CI: 0.752–0.789), and 0.812 (95% CI: 0.794–0.830), respectively, compared with waist circumference (WC), body mass index (BMI), TG to HDL ratio, and VAI via KNHANES, in a statistically significant manner. The NVAI has advantages as a predictor of visceral obesity and is significantly associated with ASCVD risks and development of major CVD and stroke in the Korean population. The NVAI could be a screening tool for improved risk estimation related to visceral obesity.

Sarcopenia has attracted interest due to its impact on various health problems. Chronic inflammation is an important contributor to sarcopenia. Thus, we aimed to investigate the association between serum alkaline phosphatase (ALP), which is a novel inflammatory marker, and muscle mass. This study included 15,579 adults from the 2008–2011 Korea National Health and Nutrition Survey. Low skeletal muscle mass index (LSMI) was defined as body mass index-adjusted appendicular skeletal muscle mass less than 0.789 for men and 0.512 for women. Multiple logistic regression revealed that the highest ALP tertile was significantly associated with LSMI compared with the lowest ALP tertile in both men [Odds ratio (OR): 1.41; 95% confidence interval (CI): 1.04–1.91] and women (OR: 1.45; 95% CI: 1.00–2.10) after adjusting for other confounders. On the receiver operating characteristic curve analysis, the predictive power was significantly higher for ALP levels than for white blood cell count in women (p < 0.001), whereas the difference was not significant in men (p = 0.515). Our findings suggest the potential use of serum ALP as an inflammatory marker and a predictor of sarcopenia.