Subclinical Hypothyroidism in Polycystic Ovary Syndrome: Prevalence and Impact on Metabolic and Cardiovascular risk

Taieb Ach; Rim Dhaffar; Fatma Ben Abdessalem; Wiem Saafi; Imen Halloul; Hamza ElFekih; Ghada Saad; Yosra Hasni

doi:10.1177/11795514251343678

Subclinical Hypothyroidism in Polycystic Ovary Syndrome: Prevalence and Impact on Metabolic and Cardiovascular risk

Clin Med Insights Endocrinol Diabetes. 2025 Jun 3:18:11795514251343678. doi: 10.1177/11795514251343678. eCollection 2025.

Authors

Taieb Ach^{1

2

3}, Rim Dhaffar¹, Fatma Ben Abdessalem^{1

2}, Wiem Saafi^{1

2}, Imen Halloul^{1

2}, Hamza ElFekih^{1

2}, Ghada Saad^{1

2}, Yosra Hasni^{1

2}

Affiliations

¹ Faculty of Medicine of Sousse, University of Sousse, Tunisia.
² Department of Endocrinology, University Hospital of Farhat Hached Sousse, Tunisia.
³ Laboratory of Exercise Physiology and Pathophysiology, University Hospital of Farhat Hached Sousse, Tunisia.

Abstract

Background: Polycystic ovary syndrome (PCOS) is a complex condition linked to long-term health risks such as cardiovascular disease, type 2 diabetes, and metabolic syndrome. Subclinical hypothyroidism (SCH) shares overlapping symptoms with PCOS, but their relationship remains debated. SCH prevalence in PCOS patients and its impact on cardiovascular and metabolic health is debated and thus warrants further research. This research examined the association between SCH and PCOS in a Tunisian clinical-based population.

Methods: We conducted a prospective cross-sectional study of 161 PCOS patients and 75 age-matched controls recruited from 2023 to 2024. All participants underwent thyroid function testing, metabolic profiling, and hormonal assays. Statistical analyses included Mann-Whitney U, Kruskal-Wallis, and chi-square tests, with age/BMI-adjusted linear regression models.

Results: Among 236 participants (161 PCOS, 75 controls), SCH prevalence was higher in PCOS patients (14.9%) compared to controls (5.3%, $p$ = .048). Adjusted for age and BMI, median TSH levels were higher in the PCOS group (2.2 mIU/L vs 1.75 mIU/L, $p$ = .006), while FT4 levels were lower (14.26 pmol/L vs 15.26 pmol/L, $p$ = .007). Positive TPOAb prevalence was higher in PCOS (12.4% vs 2.7%, $p$ = .049). TSH levels varied across PCOS phenotypes ( $p$ = .003), with Phenotypes A and B showing higher levels than Phenotype C (A > C, $p$ = .019; B > C, $p$ < .001). SCH was highest in Phenotype A. SCH in PCOS was associated with impaired glucose tolerance ( $p$ = .011), higher blood fasting glucose ( $p$ = .033), higher total cholesterol ( $p$ = .022), and hypertriglyceridemia ( $p$ = .018).

Conclusion: SCH is more prevalent in PCOS and may worsen insulin resistance and dyslipidemia. Addressing thyroid dysfunction in PCOS patients may be beneficial for more effective management strategies, ultimately improving reproductive, metabolic, and cardiovascular outcomes for affected women.

Keywords: polycystic ovary syndrome; subclinical hypothyroidism; thyroid-metabolic-risk.

Plain language summary

How Common is Mild Thyroid Problems in PCOS, and How Do They Affect Health Risks? Polycystic Ovary Syndrome (PCOS) is a common condition that affects how a woman’s ovaries work. It can cause symptoms like irregular periods, weight gain, and difficulty getting pregnant. Some women with PCOS also have a mild thyroid problem called subclinical hypothyroidism, where the thyroid gland doesn’t work as well as it should, but not enough to cause obvious symptoms. This study looked at how common this mild thyroid problem is in women with PCOS and whether it increases their risk of developing other health issues, like diabetes, high cholesterol, or heart disease. The findings suggest that subclinical hypothyroidism is more common in women with PCOS than in those without it. Additionally, having both PCOS and a mild thyroid problem may increase the risk of metabolic and cardiovascular problems, such as higher blood sugar levels, weight gain, and a greater chance of heart disease. Understanding this link is important because it could help doctors better manage PCOS and reduce the risk of long-term health problems. Women with PCOS might benefit from regular thyroid checks and early treatment if needed. This research highlights the need for more awareness and tailored care for women with PCOS to improve their overall health.