Is there a role for insulin resistance in nonobese patients with idiopathic hirsutism?

BACKGROUND: Hirsutism is the presence of terminal hairs in women in a male-like pattern. It may result from various causes of androgen excess or may be idiopathic. Controversies exist concerning the presence of insulin resistance in idiopathic hirsutism (IH) or if it is a manifestation of a high body mass index (BMI).

OBJECTIVES: To assess insulin resistance in nonobese patients with IH.

METHODS: The study included three groups of age- and BMI-matched nonobese women: 30 patients with IH (group 1), 20 patients with hirsutism associated with polycystic ovary syndrome (PCOS) (group 2) and 20 healthy controls (group 3). The pattern of obesity based on waist to hip ratio (WHR), and insulin resistance based on fasting insulin levels and the homeostasis model assessment of insulin resistance (HOMA-IR) were assessed in all the groups.

RESULTS: Sixteen patients with IH and 17 with PCOS had insulin resistance with statistically significant differences in fasting insulin levels and HOMA-IR between the three groups, between patients with IH and healthy controls and between patients with PCOS and healthy controls; there were no significant differences between patients with IH and patients with PCOS. When classified according to the pattern of obesity, 23 patients in group 1, 17 in group 2 and two in group 3 had a WHR >or= 0.85 (android obesity) with highly significant higher values of fasting insulin levels and HOMA-IR in patients with a WHR >or= 0.85 when compared with those with a WHR < 0.85.

CONCLUSIONS: Insulin resistance occurs in nonobese patients with IH and appears to be related to android obesity.