Serial ultraviolet b exposure and serum 25 hydroxy vitamin d response in young adult american blacks and whites: No racial differences

William F. Brazerol, Andrew McPhee, Francis Mimouni, Bonny L. Specker, Reginald C. Tsang

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We tested the hypothesis that repeated whole body suberythemal ultraviolet B (UVB) exposure would result in less increase of serum 25-hydroxyvitamin D (250HD) concentrations in black compared with white young adults with no significant change or racial differences in serum calciotropic hormones concentrations. Thirteen white and 7 black adults ranging from 22 to 35 years of age were submitted to sequential total body suberythemal doses of UVB (280—315 nm) biweekly for 6 weeks. Initial UVB dose was 5% below the minimal erythemal dose for the most sensitive skin, followed by 10% increase per exposure for 4 weeks. Blood samples were drawn weekly. Baseline 250HD concentrations were significantly lower in blacks compared to whites, but the increases in serum 250HD concentrations were similar in both groups; there were no significant differences by sex or age. Serum 24,25-dihydroxyvitamin D [24,25-(OH)2D] concentrations paralleled the serum 250HD response. Mean serum calcium (total and ionized), magnesium, phosphate, alkaline phosphatase, vitamin D binding protein, C-terminal parathyroid hormone, calcitonin, 1,25-dihydroxy vitamin D [l,25-(OH)2D], and osteocalcin concentrations did not differ between blacks and whites at any time. The ratio of the concentration of l,25-(OH)2D to 250HD in their serum was initially higher in blacks compared to whites (p<0.0001); the ratios decreased to levels similar to whites by the third UVB exposure. We conclude that, in blacks and whites, sequential suberythemal UVB exposure produces similar elevations of serum 250HD concentrations and unchanged calciotropic hormones concentrations. From the lack of racial difference in serum 250HD response, we suggest that sequential suberythemal ultraviolet exposure in this study resulted in maximal cutaneous previtamin D3 production, and that blacks and whites are equally capable of producing vitamin D3 at these doses.

Original languageEnglish
Pages (from-to)111-118
Number of pages8
JournalJournal of the American College of Nutrition
Issue number2
Publication statusPublished - 1 Apr 1988
Externally publishedYes

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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