Relationship between body mass index and disregulation of gonadotropins in polycystic ovary syndrome

To assess the relationship between elevated body mass index (BMI) and basal luteinizing hormone (LH) levels and ratio of LH to follicle-stimulating hormone (FSH) in polycystic ovary syndrome (PCOS), a retrospective case-control study was performed at Human Reproduction Service, Arzobispo Loayza Hospital in Lima, Peru. A total of 94 PCOS women aged between 15 and 39 years old were included. All had infertility, menstrual irregularities, hyperandrogenism and polycystic ovaries detected by ultrasonography. Patients were classified into two groups: case group with BMI>25 kg/m(2) (n=49) and control group with BMI<25 kg/m(2) (n=45). Clinical features, LH, LH/FSH ratio and insulin tolerance test were compared. Chi-square test, Mann-Whitney test and Student's t-test were used for statistical analysis. Age of menarche was 12.25 +/- 1.63 years in case group and 13.43 +/- 1.43 years in control group (p < 0.05). Ferriman's index was higher in case group: 10.75 +/- 5.5 vs. 6.5 +/- 0.71 (p < 0.05). In case group, 21.4% of patients had acanthosis nigricans compared with 2.4% in control group. LH values were 9.20 +/- 4.8 and 12.44 +/- 9.1 mUI/ml in groups with BMI greater than or equal to 25 and BMI < 25, respectively (p < 0.05). The LH/FSH ratio did not differ between both groups with values of 1.2 +/- 0.7 and 1.40 +/- 1.0, respectively. Insulin sensitivity index was reduced and there were no differences between case and control groups: 0.39 +/- 0.19 vs. 0.38 +/- 0.06, respectively. We conclude that LH levels were lower in PCOS patients with a BMI greater than or equal to 25 and there is evidence of lower insulin sensitivity both in overweight and lean PCOS women. (C) 2004 Elsevier B.V. All rights reserved.