Association of vitamin D deficiency and endometriosis - Study of fertile women

Abstract

Background:The pathophysiology of endometriosis remains inadequately understood, leading to ongoing debate regarding the roles of various factors, including vitamin D, in its etiology and severity. Low vitamin D levels have been implicated in the pathophysiology of endometriosis, potentially contributing to proliferative and inflammatory processes. Recent studies have reported conflicting associations between serum vitamin D levels and endometriosis; while some suggest a protective role of vitamin D in mitigating the risk and severity of the disease, others report no significant correlation.

Aim: To find the relationship between vitamin D status and endometriosis in fertile women.

Materialsand Methods:An observational retrospectivecase-controlstudy of reproductive age women. 360womenwere included and divided into 2 groups. In Group I-138(38.3%), fertile patients with surgically and morphologically proven diagnosesofendometriosis,and in Group II-222 (61.7%), fertile, generally healthy women of reproductive age (18-50). The association between endometriosis status and blood concentration of 25-hydroxyvitamin D (25OHD/calcifediol) was studied. Confounding factors such as age, Body Mass Index (BMI), and season were considered. The connection of vitamin 25OHD levels with the phenotype and stage of endometriosis, according to the American Society for Reproductive Medicine (ASRM) classification, was analyzed. The severity of chronic pelvic pain, menstrual cycle regularity, parity status, Antral follicle count (AFC) in connection with endometriosis, and vitamin D levels were studied. Dataanalyseswere madeusingIBMSPSS27.

Results: Extreme vitamin D deficiency (<10ng/ml) was more common in women with endometriosis than in healthy controls - 31.2% vs 7.2% (p-0.001). The mean 25OHD level in Group I (n=138) - 17.1 ng/ml was significantly (p<0.001) lower than in Group II (n=222) -20.9 ng/ml. The seasonal variations did not influence this result in vitamin D levels. In cases of deep endometriosis combined with the ovarian endometrioma or bilateral ovarian endometrioma levels of 25OHD were observed to be significantly lower compared to other - milder phenotypes. Size of endometrioma significantly negatively correlated with 25OHD levels (p<0.001 r=-0.5). The lowest mean 25OHD was identified in stage IV endometriosis according to ASRM classification and the difference in vitamin D levels between the stages was significant (p<0.001). The severity of dysmenorrhea was in negative association with 25OHD concentration independently from endometriosis status (r=-0.42 p<0.001).

Conclusion:Women with endometriosis have significantly lower 25OHD levels in the bloodstream compared to the control group, and women with advanced stages or complex forms of endometriosis are even more vitamin D deficient. This study adds weight to the hypothesis, that low vitamin D levels are associated with the severity and phenotype of the disease. More research is needed to establish causality and the potential role of vitamin D in the treatment of endometriosis.