Significant positive correlations were observed between serum apelin-12 level with age, BMI, WC, TB-fat %, TB-FM, trunk-FM, appendicular FM, FBG, fasting insulin level, HOMA-IR, triglycerides, total cholesterol, LDL, and non-HDL in both obesity groups, while serum apelin-12 level showed significant negative correlations with HDL-C in both obesity groups (Table 3). Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.