Risk of thyroid disorders after diagnosis of endometriosis: A 20-year retrospective cohort study

BACKGROUND: Emerging evidence suggests a potential link between endometriosis and thyroid disorders; however, long-term risks remain understudied. METHODS: We conducted a retrospective cohort study using data from the TriNetX global Collaborative Network. Women aged 21-60 with endometriosis who received surgical or pharmacologic treatment were included in the endometriosis cohort. The comparison cohort comprised women without endometriosis who had undergone pelvic ultrasonography. Patients with pre-existing metabolic, cardiovascular, autoimmune, or thyroid conditions were excluded. Propensity score matching was performed based on demographic characteristics and clinical factors. RESULTS: After 1:1 matching, 118,360 patients were included. Over a 20-year follow-up, the endometriosis group had significantly higher risks of several thyroid conditions, including hypothyroidism (HR 1.19; 95% CI 1.13-1.25), hyperthyroidism (HR 1.21; 95% CI 1.09-1.35), Graves' disease (HR 1.27; 95% CI 1.04-1.56), non-toxic goiter (HR 1.31; 95% CI 1.23-1.39), thyroiditis (HR 1.32; 95% CI 1.18-1.48), and both malignant (HR 1.55; 95% CI 1.21-1.97) and benign (HR 2.47; 95% CI 1.73-3.52) thyroid neoplasms. The risk of thyroid disease did not differ significantly between women who received medical management and those who received surgical management, suggesting that the association may be intrinsic to endometriosis rather than treatment-related. Additionally, a history of delivery was associated with an increased risk of hypothyroidism (HR 1.39; 95% CI 1.17-1.66). CONCLUSION: Endometriosis is associated with an elevated long-term risk of diverse thyroid diseases. These findings highlight the need for proactive thyroid monitoring in patients with endometriosis.