Objective: Several epidemiologic and mechanistic studies suggest that 25(OH) D3 levels should be maintained above 70 nmol/L for a positive effect on the health of adults. Prior studies have noted low 25(OH) D3 levels in subsets of minority populations. The objective of this study is to examine the prevalence of adequate 25(OH) D3 levels among US adults.
Method: Using data from the third National Health and Nutrition Examination Survey (NHANES III), we evaluated serum levels of 25(OH) D3 (nmol/L) among 15,390 adult participants > or = 18 years of age. Racial/ethnic grouping was by self-identification as White, Black or African American, and Hispanic.
Results: The mean levels of 25(OH) D3 were lower among the female than male participants (71.1 vs 78.7; P=.003) and among the elderly (> or = 65 years of age vs 40-59 and 18-39) than young participants. White men and women (83.0 and 76.0) had higher mean levels of vitamin D than Hispanic men and women (68.3 and 56.7; P<.0001) and than Black men and women (52.2 and 45.3; P<.0001), respectively. The prevalence of both mild-moderate and severe deficiency of vitamin D is higher among women (P<.0001) and minority populations (P<.0001). However, even among White men, 34% had low vitamin D levels.
Conclusion: Serum levels of 25(OH) D3 are below the recommended levels for a large portion of the general adult population and in most minorities. Need exists for a critical review and probable revision of current recommendations for adult vitamin D intake to maintain adequate 25(OH) D3 levels.