Randomised controlled trial of daily versus stoss vitamin D therapy in Aboriginal children

The prevalence of vitamin D deficiency has risen in countries with a high ultraviolet index and sunny environment such as Australia. There is lack of information on vitamin D status and best possible therapy in Australian Aboriginal children. We aim to (i) describe the vitamin D status in an opportunistic sample of Aboriginal children in Western Australia and (ii) compare the efficacy of oral daily vitamin D with oral stoss vitamin D therapy in this sample.

Participants were recruited from a metropolitan area (31' S) and a rural area (17' S). Those with a 25(OH)D level less than 78 nmol/L were randomised to receive daily or stoss vitamin D therapy with follow-up at 4-6 months and 9-12 months. Biochemical and clinical parameters such as 25(OH)D, alkaline phosphatase, calcium and sun exposure were collected.

Seventy-three participants were enrolled (61 from a metropolitan and 12 from a rural area). 25(OH)D levels were greater than 78 nmol/L in 9/12 (75%) participants in the rural group and 21/61 (34%) in the metropolitan group. 25(OH)D levels were less than 78 nmol/L in 43/73 (59%) participants. Of these, 34/43 (79%) were insufficient (50-78 nmol/L), 8/43 (19%) mildly deficient (27.5-50 nmol/L) and 1/43 (2%) deficient (<27.5 nmol/L). Daily vitamin D therapy had a higher average increase in 25(OH)D levels from baseline than stoss therapy; however, this was not significant.

Vitamin D insufficiency is common in Aboriginal children of Western Australia and stoss therapy is a safe alternative to daily vitamin D therapy but requires further evaluation of timing and doses.