Analysis was the occurrence of myocardial infarction, stroke, and coronary revascularisation, determined through linkage with administrative datasets, and each event was analyzed separately as secondary outcome, with survival models being used to estimate hazard ratios and 95% confidence intervals.
The study involved 21, 315 participants between the age of 60-84 years old who were given either 60 000 IU/month of vitamin D3 (n=10 662) or a placebo (n=10 653) which were taken orally for up to five years. 16 882 participants completed the intervention period: placebo 8270 (77.6%); vitamin D 8552 (80.2%).
21,302 participants were included in the analysis with a median intervention period of 5 years. Results revealed that 1,336 participants experienced major cardiovascular events, 699 from the placebo group, and 637 from the vitamin D group. The rate of major cardiovascular events was lower in the intervention group, especially among those taking cardiovascular drugs, and overall the difference in standardized cause-specific cumulative incidence at five years was -5.8 events per 1000 participants. While there was a lower rate of myocardial infarction and coronary revascularization in the treatment group, there was no difference in the rate of stroke between the two groups.
The researchers concluded that vitamin D supplementation might reduce the risk of major cardiovascular events in older people, and the findings suggest further evaluation of the role of vitamin D supplementation among those taking drugs for the prevention/treatment of cardiovascular diseases.
“This protective effect could be more marked in those taking statins or other cardiovascular drugs at baseline,” the researchers wrote, noting that further evaluation is needed to help to clarify this issue. “In the meantime, these findings suggest that conclusions that vitamin D supplementation does not alter risk of cardiovascular disease are premature,” they concluded.
