Sunlight generates vitamin D, but there are scant human data from randomised trials on which to base health policy advice about how much sun exposure is necessary to change 25(OH)D concentrations. The purpose of the study was to evaluate the feasibility of using solar ultraviolet (UV) radiation exposure to generate a change in 25(OH)D concentration in a randomised controlled trial (RCT). The intervention tested in this RCT was supervised exposure to one standard erythemal dose (SED; 100 J m-2) of solar UV radiation three days per week for three weeks with approximately 35% of the body surface area not covered by clothing. Thirty-six fair-skinned (skin type II and III) indoor workers from Brisbane, Australia were randomised into either the intervention group (n = 16) or the control group (n = 20); the latter did not receive any supervised sun exposure. We asked both groups to use sunscreen and to minimise time outdoors during the study period. We collected blood samples at baseline, once per week during the three week intervention period, and four weeks after the intervention finished. The cumulative UV radiation exposure over the intervention period measured using polysulphone badges was higher in the intervention group than in the control group (median 8 vs. 4 SEDs, p = 0.14). After three weeks, the mean serum 25(OH)D concentration increased from 60 to 65 nmol l-1 in the intervention group and from 55 to 57 nmol l-1 in the control group. After adjustment for baseline 25(OH)D, the mean change per week during the intervention phase was non-significantly higher in the intervention than in the control group (0.7 vs. 0.3; p = 0.35). This difference was not sustained during the follow-up period. Large field trials are needed to inform policy about how much natural sun exposure is required to raise 25(OH)D concentrations. This pilot identified key issues that need to be considered in the design of such a trial.
This research output has an Altmetric Attention Score of 2. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 16 April 2018.
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#21,972,100
of 32,950,213 outputs
Outputs from Photochemical & Photobiological Sciences
#1,009
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Outputs of similar age
#278,180
of 462,240 outputs
Outputs of similar age from Photochemical & Photobiological Sciences
#279
of 687 outputs
Altmetric has tracked 32,950,213 research outputs across all sources so far. This one is in the 31st percentile – i.e., 31% of other outputs scored the same or lower than it.
So far Altmetric has tracked 1,510 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 6.6. This one is in the 31st percentile – i.e., 31% of its peers scored the same or lower than it.
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We're also able to compare this research output to 687 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 54% of its contemporaries.
