Background and Aims
Vitamin D has mostly been tested in Western populations. We examined the effect of
high dose vitamin D in a population drawn predominantly from outside of Western countries.
Methods and Results
This randomized trial tested vitamin D 60,000 IU monthly in 5670 participants without
vascular disease but at increased CV risk. The primary outcome was fracture. The secondary
outcome was the composite of CV death, myocardial infarction stroke, cancer, fracture
or fall. Death was a pre-specified outcome.
Mean age was 63·9 years, and 3005 (53·0%) were female. 3034 (53·5%) participants resided
in South Asia, 1904 (33·6%) in South East Asia, 480 (8·5%) in South America, and 252
(4·4%) in other regions. Mean follow-up was 4·6 years. A fracture occurred in 20 participants
(0·2 per 100 person years) assigned to vitamin D, and 19 (0·1 per 100 person years)
assigned to placebo (HR 1·06, 95% CI 0·57-1·99, p-value = 0·86). The secondary outcome
occurred in 222 participants (1·8 per 100 person years) assigned to vitamin D, and
198 (1·6 per 100 person years) assigned to placebo (HR 1·13, 95% CI 0·93-1·37, p=0·22).
172 (1·3 per 100 person years) participants assigned to vitamin D died, compared with
135 (1·0 per 100 person years) assigned to placebo (HR 1·29, 95% CI 1·03-1·61, p=0·03).
In a population predominantly from South Asia, South East Asia and South America,
high-dose vitamin D did not reduce adverse skeletal or non-skeletal outcomes. Higher
mortality was observed in the vitamin D group.