Background: Polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance (IR) and obesity. On the other hand, obesity has been previously linked to endocrine disorders especially thyroid dysfunction. The purpose of this study was to assess thyroid function and volume in women with PCOS and to evaluate their relations to anthropometric measurements and IR.
Methods: The study enrolled 40 women with PCOS and 62 healthy women matched for age and body mass index (BMI). BMI, waist circumference (WC), homeostasis model assessment of Insulin resistance (HOMA-IR), lipid profile, androgens, thyroid function tests and thyroid volume were evaluated. PCOS women were divided according to HOMA-IR into 2 subgroups: non-insulin resistant and insulin resistant PCOS.
Results: Insulin resistant PCOS; but not total or non-insulin resistant PCOS; had significant increase in TSH, thyroid volume, and nodule prevalence than control women. Insulin resistant PCOS showed significant increase in BMI, WC, TSH and thyroid volume than non-insulin resistant PCOS. In PCOS women: TSH, thyroid volume and nodule prevalence were significantly and positively correlated with BMI, WC, fasting insulin and HOMA-IR. With multiple regression analysis BMI, WC, fasting insulin and HOMA-IR remained independently correlated with TSH, thyroid volume and nodule prevalence.
Conclusions: Women with PCOS had changes in thyroid function and volume which are linked to and associated with IR. Obesity may represent a link between IR and thyroid changes in these women.