Vitamin D Deficiency as an Independent Risk Factor for Adenomyosis: a Cross-Sectional Study

Background: The relationship between adenomyosis and vitamin D remains largely unexplored. However, emerging evidence suggests that vitamin D deficiency may increase the risk of developing adenomyosis. Methods: A cross-sectional study was conducted involving 190 patients diagnosed with adenomyosis and 185 healthy controls. Propensity score matching (PSM) was utilized to generate 91 matched pairs. Multivariate logistic regression analysis was employed to examine the relationship between vitamin D levels and the risk of adenomyosis. Additionally, receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic performance of vitamin D levels. Results: In both unmatched (44.0 nmol/L vs. 61.4 nmol/L, p < 0.001) and matched (42.3 nmol/L vs. 60.7 nmol/L, p < 0.001) groups, patients with adenomyosis exhibited significantly lower serum vitamin D levels compared to healthy controls. Multivariate logistic regression analysis demonstrated a negative association between vitamin D levels and the risk of adenomyosis in both groups. ROC analysis identified an optimal diagnostic threshold of 44.75 nmol/L for vitamin D in predicting adenomyosis. Conclusions: Reduced serum vitamin D levels represent an independent risk factor for adenomyosis, with levels below 44.75 nmol/L associated with an increased risk. These findings suggest that vitamin D supplementation may serve as a potential preventive strategy against adenomyosis.