Objective: The aim of the present study was to compare the effect of three different progestins with differing androgenicity on carbohydrate and lipid metabolism in overweight-obese younger postmenopausal women. Additionally, the relationship between testosterone and insulin resistance was assessed.
Methods: The study included 125 postmenopausal women. Estradiol (E(2)) 2 mg/day was given to 20 hysterectomized women and the remaining 105 women were randomized into three treatment groups: E(2) 2 mg/day plus dienogest 2 mg/day (n=35); E(2) 2 mg/day plus norethisterone acetate (NETA) 1 mg/day (n=35); E(2) 2 mg/day plus medroxyprogesterone acetate (MPA) 2.5 mg/day (n=35). A 75-g oral glucose tolerance test was performed at the initial and 3-month visit. Serum glucose, insulin, total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides were measured before and after treatment.
Results: A significant treatment-related increase was observed only in the E(2)/MPA group for insulin resistance (p=0.031). When the change in the insulin/glucose ratio was compared, the E(2) group was significantly different from the E(2)/MPA and E(2)/NETA groups (p=0.008 and 0.02, respectively). Only the E(2)/dienogest group showed a treatment-related increase in fasting glucose level (p=0.037). A decrease in total cholesterol and LDL-C levels was observed in all groups (p=0.004 and 0.012, respectively). The only significant decrease in HDL-C level was observed in the E(2)/NETA group (p=0.005).
Conclusion: Estrogen therapy had a positive effect on carbohydrate and lipid metabolism in overweight-obese postmenopausal women. The addition of progestin to estrogen therapy attenuated estrogen's positive effects slightly; however, the biological actions of the three different androgenic progestins used did not result in any variation.