Prevalence and correlates of vitamin D status in African American men

Abstract

Background: Few studies have examined vitamin D insufficiency in African American men although they are at very high risk. We examined the prevalence and correlates of vitamin D insufficiency among African American men in Philadelphia. Methods: Participants in this cross-sectional analysis were 194 African American men in the Philadelphia region who were enrolled in a risk assessment program for prostate cancer from 10/96–10/07. All participants completed diet and health history questionnaires and provided plasma samples, which were assessed for 25-hydroxyvitamin D (25(OH)D) concentrations. We used linear regression models to examine associations with 25(OH)D concentrations and logistic regression to estimate odds ratios (OR) for having 25(OH)D ≥ 15 ng/mL. Results: Mean 25(OH)D was 13.7 ng/mL, and 61% of men were classified as having vitamin D insufficiency (25(OH)D <15 ng/mL). Even among men with vitamin D intake ≥ 400 IU/day, 55% had 25(OH)D concentrations <15 ng/mL. In multivariate models, 25(OH)D concentrations were significantly associated with supplemental vitamin D intake (OR 4.3, 95% confidence interval (CI) 1.5, 12.4) for >400 vs. 0 IU/day), milk consumption (OR 5.9, 95% CI 2.2, 16.0 for ≥ 3.5 vs. <1 time per week), and blood collection in the summer. Additionally, 25(OH)D concentrations increased with more recreational physical activity (OR 1.3, 95% CI 1.1, 1.6 per hour). A significant inverse association of body mass index with 25(OH)D concentrations in bivariate analyses was attenuated with adjustment for season of blood collection. Conclusion: The problem of low vitamin D status in African American men may be more severe than previously reported. Future efforts to increase vitamin D recommendations and intake, such as through supplementation, are warranted to improve vitamin D status in this particularly vulnerable population.