Sun exposure levels for provision of vitamin D sufficiency in people of skin type V living in the UK
1. What is the effect on vitamin D status in people of skin type V, of the amount of UV exposure recommended for white Caucasian subjects, and how much extra UV exposure do skin type V people require?
A UV course will be given to 60 subjects in January/February, using a whole body cabinet with lamps emitting a UV spectrum similar to sunlight. Blood 25(OH)D levels measured weekly.
2. What levels of vitamin D are attained through natural sunlight exposure in skin type V individuals living in the UK? How do these relate to personal UV exposure doses? Does the relationship differ from that in white Caucasian individuals?
125 subjects will have blood 25(OH)D levels assessed once in each season, UV exposure measured through polysulphone badges and dietary vitamin D assessed through diet diaries.
The results of the experimental work in the intervention study can be related to the findings of the real population in the observation study. Moreover, both studies in skin type V volunteers can be related to the findings of the equivalent studies in the white Caucasian subjects.
North Manchester Research Ethics Committee approved on the 20th May 2008 (ref: 08/H1006/24)
Single centre non-randomised prevention and treatment trial
Primary study design
Secondary study design
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Topic: Skin; Subtopic: Skin (all Subtopics); Disease: Dermatology
1. Intervention study:
1.1. Subjects were given simulated summer's sun exposures from a constant UVR dose via a full body cabinet, 3 times a week for 6 weeks. The subjects were split into 6 groups receiving either 0.65, 1.3 1.95, 2.6, 3.2, 3.9 SED. This was given in Jan/Feb, when there is no confounding ambient UVR
1.2. Vitamin D (25(OH)D) blood samples were taken pre-intervention and then weekly for 6 weeks
1.3. Patients completed diet diaries (1st week and 6th week) to assess dietary vitamin D
2. Observational study:
2.1. Vitamin D (25(OH)D) blood samples were taken in each season of the year (April - Spring, July - Summer, October - Autumn, January - Winter)
2.2. The subjects were also given polysulphone film badges to wear on their clothes for one week in each season to measure ambient UV
2.3. Sun exposure diaries were also used to give additional information about seasonal UV exposure
2.4. A diet diary was completed in each season for dietary vitamin D assessment.
Follow up was for one year.
The interventional follow up was for 7 weeks, the actual intervention (not treatment) was carried out over 6 weeks.
Primary outcome measures
1. Intervention study: % number of people reaching sufficient levels of vitamin D following simulated summer exposure
2. Observational study: the post summer vitamin D level required to maintain sufficiency throughout the winter months
Secondary outcome measures
1. The % numbers reaching optimal levels of vitamin D following simulated summer sun exposure
2. Baseline winter levels of vitamin D deficiency, sufficiency and optimal levels
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Aged 18 - 65 years old
2. South Asian descent
3. Male or female
4. Sun-reactive skin type V
Target number of participants
Planned sample size: 185
Participant exclusion criteria
1. History of skin cancer (intervention study)
2. History of a photosensitivity disorder (both)
3. Regular sunbathing/use of sunbeds (observational study)
4. Sunbathing/use of sunbeds in the past 3 months (intervention study)
5. Taking photoactive medication (interventional)
6. Pregnant or breast-feeding (interventional)
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
University of Manchester (UK)
c/o Mohammed Zubair
FMHS Research Office
3.53 Simon Building
University of Manchester
Cancer Research UK (CRUK) (UK)
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Farrar MD, Kift R, Felton SJ, Berry JL, Durkin MT, Allan D, Vail A, Webb AR, Rhodes LE, Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin., Am. J. Clin. Nutr., 2011, 94, 5, 1219-1224, doi: 10.3945/ajcn.111.019976.
Farrar MD, Webb AR, Kift R, Durkin MT, Allan D, Herbert A, Berry JL, Rhodes LE, Efficacy of a dose range of simulated sunlight exposures in raising vitamin D status in South Asian adults: implications for targeted guidance on sun exposure., Am. J. Clin. Nutr., 2013, 97, 6, 1210-1216, doi: 10.3945/ajcn.112.052639.