Relationship between vitamin D deficiency, polycystic ovary syndrome, and serum dehydroepiandrosterone levels

Polycystic ovary syndrome (PCOS) is a multifaceted endocrine disorder characterized by heterogeneous clinical and metabolic features. Although previous research has frequently reported an association between vitamin D deficiency and PCOS, the clinical implications of this relationship remain uncertain. In particular, the potential interaction between vitamin D status, clinical manifestations, and dehydroepiandrosterone sulfate (DHEAS) levels has not been clearly established. In this study, we aimed to explore the relationship between serum vitamin D levels and DHEAS concentrations in women with PCOS, while also assessing their associations with key clinical parameters. A total of 230 women diagnosed according to the Rotterdam 2003 criteria were retrospectively evaluated. Patients were grouped according to vitamin D status as severe deficiency, deficiency, insufficiency, and sufficiency, and they were also classified according to normal or elevated DHEAS levels. Demographic characteristics, clinical findings, hormonal profiles, and biochemical parameters were obtained from electronic medical records, reflecting routine clinical practice. Statistical analyses were performed using appropriate parametric and non-parametric methods. Vitamin D deficiency was highly prevalent in the study population: severe deficiency was observed in 108 patients (47.0%), deficiency in 100 patients (43.5%), insufficiency in 13 patients (5.9%), and sufficiency in only 9 patients (4.1%). No statistically significant association was found between vitamin D categories and DHEAS levels (p = 0.73), infertility status (p = 0.85), hirsutism severity (p = 0.68), or menstrual interval (p = 0.27). Although reduced vitamin D levels were commonly observed, this did not translate into measurable differences in clinical outcomes. One possible explanation is the high baseline prevalence of vitamin D deficiency in the general population, which may obscure disease-specific effects. In addition, the deficiency lack of association between vitamin D status and DHEAS suggests that androgen excess in PCOS may be regulated by mechanisms independent of vitamin D.