Association of covariates and endometriosis risk.

Endometriosis is a multifactorial disease associated with inflammation. Vitamin D has anti-inflammatory, antiproliferative, anti-oxidative, and immunomodulatory effects. Whether vitamin D levels are correlated with endometriosis is a subject of ongoing debate. This study aimed to examine the association between endometriosis and serum vitamin D levels. From the National Health and Nutrition Examination Survey, this study examined the cross-sectional data of American women aged 20–54 years from 2001 to 2006. After adjusting for covariates, multivariable logistic regression analysis was used to assess correlations. A total of 3,232 women were included in this study. The multiple linear regression model demonstrated a negative correlation between the serum 25-hydroxyvitamin D3 (cholecalciferol) concentration and the risk of endometriosis after controlling for all confounding variables. The odds ratio was 0.73 with a 95% confidence interval of 0.54–0.97 in the adequate vitamin D level group compared with the insufficient vitamin D level group. Our results showed that endometriosis was inversely correlated with serum 25-hydroxyvitamin D3 levels. Further research is needed to establish a causal relationship and determine the potential benefits of maintaining sufficient vitamin D levels for endometriosis prevention.