Age- and Sex-Specific Associations Between Hashimoto's Thyroiditis and Metabolic Syndrome: A Retrospective Clinical Analysis

Abstract

Hashimoto's thyroiditis (HT) is the most common autoimmune thyroid disorder and is frequently associated with metabolic alterations. Metabolic syndrome (MetS), a constellation of metabolic abnormalities that increase cardiovascular risk, has been increasingly linked to thyroid dysfunction, especially in ageing populations. This study aims to evaluate the association between HT and MetS,  with emphasis on age- and sex-related differences in a hospital-based cohort.  A retrospective analysis was conducted on 499 patients diagnosed with HT at  “St. George” University Hospital, Plovdiv, Bulgaria, between October 2019  and December 2021. Data included anthropometric measurements, thyroid hormone levels, lipid and glucose profiles, and the presence of MetS based on the Joint Interim Statement criteria. Patients were stratified by sex and by decade-based age groups. MetS was diagnosed in 64 out of 499 patients (12.8%), with highest prevalence in the 51–61 (39.1%) and 62–72 (29.7%) age groups. Females  comprised 71.9% of MetS cases. A significant positive correlation between TSH and age (p<0.0001) was observed. No significant sex difference in mean TSH  levels was found. TSH levels tended to rise with advancing age, suggesting age-related hypothalamic-pituitary-thyroid axis modulation. The findings underscore the importance of evaluating MetS risk in patients with Hashimoto's thyroiditis, particularly in postmenopausal women. Age-related endocrine changes and autoimmune activity may synergistically elevate metabolic risk.