Circulating Leptin and Osteoprotegerin Levels Affect Insulin Resistance in Healthy Premenopausal Obese Women1

We investigated the relationship between circulating leptin and osteoprotegerin (OPG) levels and insulin resistance assessed by HOMA-IR in premenopausal obese and normal weight women. Thirty four obese women (age 31 ± 8 years) (BMI 35 ± 4 kg/m2) with 19 healthy controls (age 31 ± 7 years) (BMI <25 kg/m2) (BMI 21 ± 2 kg/m2) were included in the study. Women were healthy and had no osteoporosis. Circulating leptin levels were significantly higher in obese women (17.11 ± 2.05 ng/mL vs. 8.38 ± 4.71 ng/mL, p <0.0001) and decreased OPG levels were found (14.7 ± 7.15 pg/mL vs. 19.17 ± 6.37 pg/mL, p = 0.03). Leptin showed a positive correlation with BMI (r = 0.851, p <0.0001), waist-to-hip ratio (r = 0.692, p <0.0001), fasting insulin (r = 0.441, p <0.001), HOMA-IR (r = 0.412, p = 0.002), fibrinogen (r = 0.387, p = 0.004), uric acid (r = 0.293, p = 0.033), hematocrit (r = 0.394, p = 0.003), systolic (r = 0.504, p <0.0001), and diastolic blood pressure (r = 0.363, p = 0.008). OPG showed a negative correlation with insulin (r = −0.341, p = 0.013) and HOMA-IR (r = −0.324, p = 0.018). In obese women group, the regression equation of HOMA-IR was (HOMA-IR = [0.095 × leptin]–[0.051 × OPG] + 1.71). However, there was no relation between leptin and OPG levels.In conclusion, circulating leptin and OPG levels were related to insulin resistance in premenopausal obese women. However, leptin had no interference in OPG in premenopausal women.