Abstract
BACKGROUND: Previous studies have reported inconsistent associations between serum vitamin D levels and bacterial vaginosis (BV). Therefore, this study aimed to comprehensively investigate the relationship between serum vitamin D concentrations and BV risk among adult women in the United States. METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) 2001-2004 were analyzed. Multivariate logistic regression was used to assess the association between serum vitamin D levels and BV. Additionally, smoothing curve fitting and subgroup analyses were performed to explore potential non-linear relationships and effect modifications. RESULTS: A total of 1,397 adult women were included. After adjusting for multiple covariates, serum vitamin D levels showed a significant non-linear negative association with BV risk. Subgroup analyses revealed that this association was not statistically significant among certain ethnic groups and women with lower body mass index (BMI). CONCLUSION: Serum vitamin D levels were non-linearly and negatively associated with the risk of bacterial vaginosis in adult women in the United States. Notably, the association was no longer present at serum vitamin D concentrations ≥63.1 nmol/L, which may inform future research.