Limited exposure to ambient ultraviolet radiation and 25‐hydroxyvitamin D levels: a systematic review

What this study found

Overall, many adults were able to maintain adequate serum 25-hydroxyvitamin D levels for several months even in the absence or near absence of UVR, although UVR remained important for many groups. In the reported submariner arms, both vitamin D 400 IU daily plus a fortified diet and a fortified diet alone were associated with adequate mean serum 25(OH)D levels. The authors concluded that prior UVR exposure and vitamin D stores may help maintain status, and that dietary vitamin D or supplementation could be useful public health strategies to reduce insufficiency while avoiding UVR risks.

Study & population

Systematic review of 41 studies and 56 datasets involving 4211 healthy adults living with little or no ambient ultraviolet radiation exposure because of season, location, clothing, or occupation.

Intervention

The active regimen was oral vitamin D supplementation, reported as 400 IU daily, sometimes alongside a vitamin D-fortified diet.

Key limitation

The evidence base was heterogeneous in population, exposure conditions, and intervention reporting, limiting direct comparison across studies.

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