Vitamin D and methicillin-resistant Staphylococcus aureus nasal carriage.

Studies have found that vitamin D plays an important role in mediating immune function via a number of pathways, including enhancing the release of antimicrobial peptides in the skin. Given these findings, we hypothesize that low serum vitamin D levels may increase the risk of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). A secondary data analysis of the National Health and Nutrition Examination Survey 2001-2004 was performed to investigate the association between serum vitamin D levels and MRSA nasal carriage for the non-institutionalized population of the USA. An estimated 2.7 million persons (1.2% of the population) are MRSA nasal carriers. An estimated 63.3 million persons (28.4% of the population) are vitamin D deficient (serum vitamin D <20 ng/ml). In an adjusted logistic regression analysis controlling for age, race, gender, poverty income ratio, current health status, hospitalization in the past 12 months, and antibiotic use in the past month, individuals with vitamin D deficiency had a statistically significant increased risk of MRSA carriage of 2.04 (95% CI 1.09-3.84). Vitamin D deficiency is associated with an increased risk of MRSA nasal carriage. Further trials may be warranted to determine whether vitamin D supplementation decreases the risk of MRSA colonization.