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

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.