Sun Exposure and Vitamin D Supplementation for mild vitamin D insufficiency in Australian Adults

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Vitamin D deficiency is common in Australia. But Australia has high skin cancer incidence. While advice is given on safe sun exposure to avoid the risks of skin cancer, it is not clear how much sun exposure is required, at different locations in Australia, to maintain sufficient vitamin D levels throughout the year. This study thus addresses the following public health questions: 1). Can safe patterns and doses of sunlight exposure achieve and maintain vitamin D adequacy with no vitamin D supplementation? and 2). How does sun exposure advice calibrate against 2 different doses of vitamin D3 supplementation to manage mild vitamin D deficiency? We will recruit 228 Australian adults aged 18-64 years who have been diagnosed with mild vitamin D deficiency on routine testing (25(OH)D of 40-60nmol/L) in each of four regions in Australia - Canberra, Melbourne, Brisbane, Perth. Participants will be randomly allocated to one of four groups receiving different types of sun exposure advice and supplementation. Outcomes will be the proportion of participants who are vitamin D sufficient at 12 months, and at the end of winter, the time when vitamin D levels are usually lowest.