Thyroid autoimmunity in different phenotypes of polycystic ovary syndrome: a single-center experience

Polycystic ovary syndrome (PCOS) has been associated with Hashimoto's thyroiditis (HT) and 4 phenotypes have been described in this syndrome. The aim of this work was to investigate the frequency of anti-thyroid antibodies (TAb) and thyroid function in the 4 phenotypes of PCOS.

This study included 448 patients with PCOS: 260 (58.0%) with phenotype A, 119 (26.6%) with phenotype B, 38 (8.5%) with phenotype C and 31 (6.9%) with phenotype D.

TAb positivity was detected in 90/448 patients (20.1%) and was statistically significant higher (p = 0.03) in the grouped phenotypes A-B (83/379, 21.9%) than in phenotypes C-D (7/69, 10.1%). Positive anti-thyroglobulin antibodies (TgAb) were detected in 74/448 (16.5%) patients and positive anti-thyroperoxidase antibodies (TPOAb) in 66/448 (14.7%) patients. Both TgAb and TPOAb positivity was higher but not statistically significant in phenotype A-B than phenotype C-D. High titer TgAb (> 100 UI/ml) frequency was significantly higher (p = 0.005) in grouped phenotypes A-B (39/379, 10.3%) than in phenotypes C-D (0/69, 0.0%), while no significant difference was observed for low titer TgAb (≤ 100 UI/ml). According to a binary logistic regression analysis hypothyroidism was significantly associated with TAb positivity (OR 4.19; CI 2.25-7.79; p < 0.01) but not with PCOS phenotype. Androgen profile was not associated with TAb positivity.

A higher frequency of positive TAb and of high titer TgAb and TPOAb have been detected in PCOS women with phenotypes A and B, probably in relation to the greater imbalances between estrogen and progesterone levels present in these phenotypes.