Many adults maintain adequate vitamin D with minimal UVR

(HealthDay)—Many adults maintain adequate serum 25-hydroxyvitamin D [25(OH)D] levels even in periods of minimal ultraviolet radiation (UVR) exposure, according to a study published online Feb. 3 in the British Journal of Dermatology.

Shantini A. Rice, M.D., from the University of Southampton in the United Kingdom, and colleagues conducted a systematic review to determine the requirement for UVR in maintaining adequate (>50 nmol L⁻¹) serum 25(OH)D levels. Data were included from 41 studies with a total of 4,211 healthy adults from 56 data sets.

The researchers found that in 10 of 19 data sets reporting winter levels in areas with limited UVR, over 50 percent of subjects had >50 nmol L⁻¹ 25(OH)D. In four of 12 data sets from polar regions during period of negligible UVR, more than 50 percent of subjects had adequate 25(OH)D levels. Adequate 25(OH)D levels were also reported in one of nine data sets documenting clothing-related minimal UVR and two of eight data sets describing employment-related minimal UVR.

"The data demonstrate that many adults maintain adequate serum vitamin D levels despite negligible UVR exposure for several months," the authors write. "However, we acknowledge that preceding UVR exposure leading to vitamin D storage and delayed release may account for this maintenance of adequate serum vitamin D levels."

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