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.