The influence of waist circumference on insulin resistance and nonalcoholic fatty liver disease in apparently healthy Korean adults

Background/AimsWaist circumference (WC) is a risk factor for metabolic syndrome and is related to insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to determine the association between WC and IR and NAFLD in apparently healthy Korean adults.MethodsThe volunteers included in this cross-sectional study comprised 9,159 adults (5,052 men, 4,107 women) who participated in a comprehensive health checkup program. IR was evaluated by the homeostasis model assessment of IR (HOMA-IR) and was considered to be present when the HOMA-IR score was >2. NAFLD was evaluated by ultrasound examination. Elevated alanine aminotransferase (ALT) was defined as >40 IU/L in men and >35 IU/L in women. Logistic regression was performed to determine the odds ratios (ORs) and 95% confidence intervals (95% CIs) for NAFLD, IR, and ALT according to categorized levels of WC.ResultsNAFLD was found in 2,553 (27.9%) of the participants (82.6% men, 17.4% women), while IR and elevated ALT were found in 17.2% (68.1% men, 31.9% women) and 10% (83% men, 17% women), respectively. After adjusting for confounding factors, the prevalence of NAFLD, IR, and elevated ALT was significantly associated with increases in WC quartile: highest quartile for NAFLD in men, OR=15.539, 95% CI=12.687-19.033; highest quartile for NAFLD in women, OR=48.732, 95% CI=23.918-99.288 (P