Cut-Off Values for Visceral Fat Area Identifying Korean Adults at Risk for Metabolic Syndrome / 가정의학회지

BACKGROUND: Cut-off values for visceral fat area (VFA) measured by computed tomography (CT) for identifying individuals at risk of metabolic syndrome (MetS) have not been clearly established in Korean adults, particularly for large populations. We aimed to identify optimal VFA and waist circumference (WC) cut-off values and compare the ability of VFA and WC to predict the presence of ≥2 metabolic risk factors. METHODS: We included 36,783 subjects aged 19–79 years undergoing abdominal fat CT during regular health checkups between January 2007 and February 2015 in Seoul. The risk factors for MetS except WC were based on the International Diabetes Federation criteria. Receiver operating characteristic curve analyses were used to determine the appropriate VFA and WC cut-off values for MetS. RESULTS: VFA was a more significant predictor of metabolic risk factors than WC and body mass index (BMI). The optimal cut-off values for VFA and WC were 134.6 cm2 and 88 cm for men and 91.1 cm2 and 81 cm for women, respectively. We estimated age-specific cut-off values for VFA, WC, and BMI. VFA cut-off values increased with age, particularly among women. CONCLUSION: This large population study proposed the cut-off values for VFA and WC for identifying subjects at risk of MetS among Korean adults. For more accurate diagnosis, different age-specific cut-off values for VFA and WC may be considered.

Is Vitamin D an Independent Risk Factor of Nonalcoholic Fatty Liver Disease?: a Cross-Sectional Study of the Healthy Population

The association between vitamin D levels and nonalcoholic fatty liver disease (NAFLD) has been recognized. However, few studies showed independent associations between vitamin D deficiency and NAFLD after a sex-related adjustment for metabolic factors. We aimed to study whether vitamin D deficiency is an independent risk factor of NAFLD even after controlling for metabolic syndrome and visceral fat in both sexes. In this cross-sectional study, 7,514 Korean adults (5,278 men, 2,236 women) participated in a health check-up program. They underwent blood tests, abdominal computed tomography (CT) of the visceral fat area, and ultrasonography for NAFLD screening. Multiple logistic regression analysis was used to investigate the association of vitamin D deficiency with NAFLD according to the sex differences. Vitamin D deficiency is associated with NAFLD. The adjusted odds ratio (aOR) for NAFLD increased sequentially with decreasing vitamin D level, even after adjusting for metabolic syndrome and visceral fat. The subjects in the vitamin D sufficiency group (20–30 ng/mL) had an aOR for NAFLD of 1.18 (95% CI, 1.00–1.39), whereas the deficiency group (< 20 ng/mL) had an aOR of 1.29 (95% CI, 1.10–1.52). However, we have detected a significant sex-related interaction when analyzing the results. A significant relationship between vitamin D deficiency and NAFLD was found in men (aOR, 1.33; 95% CI, 1.11–1.60) but not in women.