Endocrine Abstracts

Background: Polycystic ovary syndrome (PCOS) could be associated with increased risk of thyroid disorders. Possible associations between TSH and cardio-metabolic risk in PCOS are debated.

Methods: National Register-based study on women with PCOS in Denmark. 18,476 women had a diagnosis of PCOS in the Danish National Patient Register. PCOS Odense University Hospital (OUH, N=1,146) was an embedded cohort including premenopausal women with PCOS and clinical and biochemical examination. Three age-matched controls were included per patient in PCOS Denmark (N=54,757). The main study outcome was thyroid disease (myxedema, struma, Graves disease, thyroiditis) defined according to nationwide in- and outpatient hospital contact diagnosis codes and/or inferred from filled medicine prescriptions. A possible link between baseline TSH and development of cardio-metabolic disease (ICD10 codes and/or medical treatment for diabetes and cardiovascular disease including hypertension) was examined in PCOS OUH.

Results: The age at inclusion was median (quartiles) 29 (23–35) years and follow up was 11.1 (6.9–16.0) years. The Hazard ratio (95% CI) for development of thyroid disease was 2.5 (2.3; 2.7) (P<0.001) and the total event rate of thyroid disease was 6.0 per 1,000 patient years in PCOS Denmark vs. 2.4 per 1,000 patient years in controls (P<0.001). Women in PCOS OUH with TSH ≥2.5 mU/L (n=133) had higher BMI (median 29 vs. 27 kg/m²), higher waist, higher triglycerides, and higher free testosterone by the time of PCOS diagnosis compared to women in PCOS OUH with TSH <2.5 mU/L (n=588). Baseline TSH did not predict later development of cardio-metabolic diseases in PCOS OUH.

Conclusion: The event rate of thyroid disease was higher in women with PCOS compared to controls. Baseline TSH was associated with PCOS metabolic phenotype, but did not predict development of cardio-metabolic disease.