The effects of metformin on metabolic and cardiovascular risk factors in nonobese women with polycystic ovary syndrome.

Objective: There are conflicting data regarding the effects of metformin in lean women with polycystic ovary syndrome (PCOS). Thus, our aim was to evaluate the effects of 6 months of metformin therapy on various metabolic and cardiovascular risk factors in lean women with PCOS.

Design: This was a prospective clinical study performed in a University hospital.

Patients: Twenty nonobese PCOS women and 20 age- and BMI-matched healthy women were included in the study. Metformin (2550 mg/day) was administered for 6 months in women with PCOS. The hormonal and metabolic parameters were evaluated before and after metformin treatment.

Measurements: The main outcome measures were serum androgens, FSH, LH, oestradiol, 17-hydroxyprogesterone, glucose, insulin, lipid profile, lipoprotein(a) [Lp(a)] and homocysteine levels. In addition 24-h ambulatory blood pressure monitoring (ABPM) and carotid intima-media thickness (IMT) were taken.

Results: After 6 months of metformin therapy, women with PCOS had decreased LH, total testosterone, free androgen index and slightly increased SHBG levels. Metformin treatment resulted in resumption of regular menses in 12 (60%) patients, and in 8 (40%) of them serum progesterone level was compatible with ovulation. Glucose and insulin responses to oral glucose tolerance test (OGTT) and homeostasis model assessment of insulin resistance (HOMA-IR) did not improve after the metformin therapy. There were no significant changes in terms of cardiovascular risk factors such as lipids and homocysteine, IMT and ABPM.

Conclusion: Metformin may have beneficial effects in lean PCOS women in terms of resumption of menses without any remarkable effect on metabolic and cardiovascular risk factors.