Neck Circumference as a Predictor of Insulin Resistance in People with Non-alcoholic Fatty Liver Disease

BACKGROUND: Insulin resistance is common in individuals with non-alcoholic fatty liver disease (NAFLD). Because insulin resistance is a predictive factor for advanced liver diseases in people with NAFLD, efforts have been made to predict it through anthropometric variables. Recently, neck circumference (NC) has been regarded as a reliable alternative marker for metabolic disorders. This study verified the association between NC and insulin resistance in patients with NAFLD. METHODS: We analyzed data from 847 people with NAFLD who participated in the 2019 Korean National Health and Nutrition Examination Survey. NAFLD was defined by a hepatic steatosis index score of ≥36 points, and insulin resistance was defined by a homeostatic model assessment of insulin resistance score of ≥2.5 points. Participants were divided according to sex-specific NC tertiles (T1, lowest; T2, middle; T3, highest). RESULTS: In the analysis of the area under the receiver operating characteristic curve (AUC), NC displayed a greater predictive power than body mass index (BMI) for insulin resistance in women (AUC of NC=0.625 vs. AUC of BMI=0.573, P=0.035). NC and the odds ratio (OR) for insulin resistance showed a cubic relationship in both men and women. In the weighted multiple logistic regression analysis, the ORs with 95% confidence intervals for insulin resistance in people with NAFLD in T2 and T3 compared to the reference tertile (T1) were 1.06 (0.47–2.41) and 1.13 (0.41–3.11), respectively, in men and 1.12 (0.64–1.97) and 2.54 (1.19–5.39), respectively, in women, after adjusting for confounding factors. CONCLUSION: NC was positively correlated with insulin resistance in women with NAFLD.