Does the relationship between 25-hydroxyvitamin D status and bone mass vary according to skin color in adults? Results of a Brazilian population-based study.

Skin color has been indicated as an important factor in determining serum concentrations of 25-hydroxyvitamin D [25(OH)D], and consequently bone health. However, studies are controversial and scarce for mixed populations. PURPOSE/INTRODUCTION To analyze the association of 25(OH)D with bone mineral content (BMC) and bone mineral density (BMD); and to investigate the presence of interaction with skin color in Brazilian adults. METHODS This is a cross-sectional, population-based study conducted with adult individuals (20-59 years) of both genders. Bone health was assessed by dual energy radiological absortometry. Vitamin D status was measured using serum 25(OH)D. Skin color and other variables in the adjusted model were collected using a questionnaire and anthropometric assessment. Associations and interactions were evaluated using linear regression models stratified according to gender. RESULTS Non-white men with vitamin D deficiency ( 0.05 for all tests) in either gender and for all bone sites evaluated. CONCLUSION Deficient vitamin D status is associated with lower bone mass in adults with differences observed according to gender, but not according to skin color.