None listed
Conditions
Brief summary
The study hypothesis is that UVB, which increases body levels of vitamin D, when given to vitamin D deficient people in winter when the sun is weak, will lower blood pressure and insulin resistance, and improve cardiac function, compared with UVA which has no effect on vitamin D synthesis. All participants, both interviewers and myself will be blind to intervention. The UV is given by a nurse at a private dermatology clinic. She, the dermatologist at the clinic and the 3 members of an independent data monitoring committee, are the only people who know the allocation of the UV; plus a data entry person working for the data entry committee who keeps the baseline and follow-up bood results and who has no contact with participants.
Interventions
A randomised double-blind clinical trial comparing ultraviolet B radiation (treatment) with ultraviolet A radiation (control), given twice weekly for 12 weeks. UVB will start at 400mJ/cm2 (with 20% increments) in the Pacific participants, and start at 200 mJ/cm2 (with 5% increments) in the European participants. UVA treatments will start with 1 J/cm2 the first week (with 1 J/cm2 weekly increases to 6 J/cm2 and maintained) in Pacific p
A randomised double-blind clinical trial comparing ultraviolet B radiation (treatment) with ultraviolet A radiation (control), given twice weekly for 12 weeks. UVB will start at 400mJ/cm2 (with 20% increments) in the Pacific participants, and start at 200 mJ/cm2 (with 5% increments) in the European participants. UVA treatments will start with 1 J/cm2 the first week (with 1 J/cm2 weekly increases to 6 J/cm2 and maintained) in Pacific participants, and start at 0.5 J/cm2 (with 0.5 J/cm2 weekly increases up to 3 J/cm2 and maintained) in European participants. UVB increases vitamin D (in contrast with UVA which is the control).
Sponsors
Health Research Council of New Zealand
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
50 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Age - Pacific Island and Maori >50years, European >65years; 25OHD levels < 50 nmol/L.
Exclusion criteria
Hypertension treated with thiazide diuretics, diabetes treated with insulin or oral hypoglycaemics, taking vitamin D supplements (including cod liver oil), planned travel to areas with high sun exposure during the study period.
Outcome results
None listed