A pilot trial of vitamin D for the reduction of chronic disease and mortality in older adults.

Observational studies, mostly from Europe and North America, suggest that people with low vitamin D status may have increased risks of some chronic diseases and death. Given that sunlight is essential for vitamin D synthesis this has prompted calls from some to relax sun protection messages or so increased population-wide vitamin D supplementation through expanded mandatory food fortification. However there is no strong evidence from clinical trials to support these measures and the International Agency for Research on Cancer has specifically called for randomised trials of high dose vitamin D supplementation for prevention of cancer and lowering of total mortality. We propose here to assess the feasibility of such a trial in the four eastern states of Australia. Participants randomly selected from the electoral roll will be invited to participate, and randomly assigned to a monthly intake of one of two vitamin D doses (60,000 IU/month or 30,000 IU/month) or placebo for 12 months. Baseline and post-intervention serum vitamin D levels will be measured. Outcomes will be recruitment rate, representativeness of the general population, change in vitamin D levels according to population subgroup and economics.