Relationship between vitamin D levels and age of menopause and reproductive lifespan: Analysis based on the National health and nutrition examination survey (NHANES) 2001–2018

Abstract

ObjectivesTo determine the association between serum vitamin D levels and age at menopause and reproductive lifespan in a group of US postmenopausal women. Study designData from 6,326 postmenopausal US women in the National Health and Nutrition Examination Survey (NHANES) database 2001–2018 were obtained. Weighted multinomial logistic regression models were used to obtain odds ratios (OR) and 95% confidence intervals (CI). Statistical analyzes were performed using SAS (version 9.4; SAS Institute), and complex survey designs were considered. ResultsVitamin D deficiency was associated with a higher likelihood of early menopause (OR = 1.34, 95% CI: 1.15, 1.58; p = 0.008) and lower odds of late menopause (OR = 0.79, 95% CI: 0.52, 0.95) in the unadjusted model but not in the adjusted model. Lower vitamin D levels were associated with a higher risk of a shorter reproductive lifespan. The strongest association was seen in the first tertile of vitamin D deficiency (OR = 1.54; 95% CI: 1:29–1:83). After adjustment, the associations were somewhat weakened but remained statistically significant. ConclusionsThe results of this study suggest that vitamin D deficiency and inadequacy might be associated with earlier age at menopause. It may also reduce the reproductive lifespan in women. Given the cross-sectional nature of the NHANES dataset, these results should be interpreted with caution due to temporality bias. Menopausal age is a multifactorial phenomenon, and the identification of factors and their interactions should be evaluated in future studies.