Neck to Waist Circumference Ratio and Insulin Resistance in Adult Korean Population Under 50 Years

To investigate the association between neck to waist circumference (N/W) ratio and insulin resistance in the adult general population under 50 years. We analyzed data from the 2020 Korea Health National Analysis Nutrition Examination Survey (KNHANES) to examine the relationship between N/W ratio and insulin resistance in the general population under 50. After adjusting for age, sex, and various cardiometabolic variables, the N/W ratio was significantly associated with fasting blood glucose, insulin, HbA1c, and homeostatic model assessment of insulin resistance (HOMA-IR) index, as well as BMI (p < 0.01). In the lowest N/W ratio quartile (Q1), metabolic risk indicators including BMI, waist circumference, blood pressure, fasting plasma glucose, HDL cholesterol, and HOMA-IR index were notably higher than those in the highest quartile (Q4) (p < 0.0001). This suggests that a higher N/W ratio may be associated with a lower metabolic risk profile. The N/W ratio is a significant predictor of insulin resistance, independent of other risk factors, in the general Korean population under 50. These findings underscore the utility of the N/W ratio as an accessible screening tool for assessing cardiometabolic risks.