Changes in serum 25-hydroxyvitamin D and cholecalciferol after one whole-body exposure in a commercial tanning bed: a randomized study.
Level 2 - randomized trial
Individual randomized controlled trial with a placebo comparator
PubMed 22391940 · doi:10.1007/s12020-012-9641-z
What was done
Twenty healthy volunteers were randomized to receive a single whole-body exposure in either a commercial tanning bed emitting UVB radiation (UVB/UVA ratio 1.8–2.0%, output 450 µW/cm²; n = 11) or an identical placebo tanning bed without UVB emission (n = 9). Blood samples were collected at baseline and monitored over 7 days to measure serum 25-hydroxyvitamin D (25OHD) and cholecalciferol.
What was found
During the first 6 hours, 25OHD showed no significant difference between groups, while cholecalciferol showed a near-significant increase of 1 pmol/l per hour in the UVB group versus placebo (p = 0.052). At day 7, raw mean 25OHD increased by 4.5 nmol/l (SD 7 nmol/l) with UVB versus a decline of -1.2 nmol/l (SD 7 nmol/l) with placebo (p = 0.1). A linear mixed model indicated a significant increase of 1.0 nmol/l per 24 hours in the UVB group (p < 0.01).
Why it matters
This study provides controlled kinetic data on vitamin D synthesis from commercial tanning equipment, demonstrating that a single whole-body session produces only a modest rise in circulating 25OHD over one week.
Limits
The study is limited by a very small sample size (n = 20), resulting in low statistical power for crude group comparisons. The abstract omits participant skin phototypes, baseline vitamin D status, exact exposure duration, and adverse effects.
Cited by
- supports UVA radiation tans the skin but does not produce vitamin D.