High prevalence of chronic thyroiditis in patients with polycystic ovary syndrome

Objective: A higher prevalence (26.9% versus 8.3% of controls) of autoimmune thyroiditis (AIT) in polycystic ovary syndrome (PCOS) has been reported in one study to date. We aimed to evaluate the prevalence of clinical, subclinical, potential thyroid autoimmune diseases and other organ-specific autoimmunity in a group of Italian patients with PCOS. Study design: 113 consecutive patients referred to our endocrinology unit as outpatients over 18 months, and diagnosed with PCOS according to the Rotterdam criteria, were included in the study, and 100 age-matched healthy women were enrolled as controls. Each patient was evaluated for family and personal history of autoimmune and non-autoimmune diseases and tested for autoantibodies against thyroperoxidase, thyroglobulin, parietal cells, intrinsic factor, adrenal-cortex, 21-hydroxylase, steroid-producing cells, 17-alpha-hydroxylase, side-chain cleavage enzyme, islet-cells, glutamic-acid decarboxylase, nuclei and mitochondria. All patients had serum TSH, FT4 and FT3 tested and patients with thyroid autoantibodies and/or abnormal TSH levels had an ultrasound thyroid scan. An oral glucose tolerance test and measurements of serum anti-Mullerian hormone (AMH) and inhibin B levels were carried out. Results: AIT was present in 30/113 (27%) patients compared with 8% of controls (p < 0.001). Subclinical hypothyroidism was detected in 13/30 (43%) patients with All; the remaining patients had normal thyroid function. The prevalence of non-thyroid autoantibodies in PCOS patients was not different from controls. AMH concentration was higher in PCOS patients compared to controls, but there was no difference between AIT and non-AIT groups. Conclusions: The prevalence of AIT in patients with PCOS was significantly higher than in controls. No other autoimmune diseases were associated with PCOS. This observation suggests that PCOS patients should be screened for AIT.