The effect of body mass index on optimal vitamin D status in U.S. adults: the National Health and Nutrition Examination Survey 2001-2006.

OBJECTIVES: To investigate the relationship between body mass index (BMI) and optimal vitamin D status in U.S. adults.
METHODS: Data on 12,927 adults 18 years and older participating in National Health and Nutrition Examination Surveys 2001-2006 were used. Serum levels of 25-hydroxy vitamin D 30 ng/mL or greater was used as a measure of vitamin D sufficiency. Log-binomial regression was used to estimate the strength of the association between BMI categories and the prevalence of vitamin D sufficiency before and after adjusting for selected characteristics.
RESULTS: After adjustment, overweight and obese individuals were 24% and 55%, respectively, less likely to have a 25-hydroxy vitamin D level of 30 ng/mL or greater compared with their normal-weight counterparts.
CONCLUSIONS: Our findings call attention to the importance of identifying individuals at risk for vitamin D insufficiency and its potential adverse health outcomes because the latter may increase health disparities in the U.S. population. If vitamin D insufficiency is implicated for chronic diseases such as cardiovascular diseases and diabetes, a vitamin D supplementation regimen would need to be readdressed, especially for segments of the U.S. population with greater BMIs.