Although the overall risk difference was small, additional assessment is justified, especially in individuals taking statins or other medications for cardiovascular disease.
Cardiovascular disease is a general term for diseases that affect the blood vessels or heart and is one of the primary causes of death worldwide. Cardiovascular disease events which include strokes and heart attacks are going to increase as populations carry on aging and chronic disease becomes more common.
Studies of an observational nature have routinely shown a connection between levels of vitamin D and the risk of cardiovascular disease, but randomized controlled studies haven’t found any evidence that vitamin D supplementation prevents cardiovascular events, possibly as a result of differences in study design that can impact results.
Researchers therefore set out to take a look at whether supplementing older individuals with monthly vitamin D doses changes the major cardiovascular event rate.
The D-Health Trial involved 21,315 individuals between the ages of 60 and 84 who were randomly given 1 capsule of either placebo or 60,000 IU vitamin D orally taken at the start of every month for about 5 years.
Individuals with a history of kidney stones, high levels of calcium known as hypocalcemia, soft bones known as osteomalacia, overactive thyroid known as hyperparathyroidism, an inflammatory disease known as sarcoidosis, or individuals already taking over 500 IU of vitamin D every day were excluded from the study.
Hospital admission and death data were then made use of for identifying major cardiovascular events, such as strokes, heart attacks, and treatment for restoring normal heart blood flow known as coronary revascularization.
The average duration of treatment was 5 years and over 80% of individuals reported taking a minimum of 80% of the tablets used in the study.
Throughout the study, 1,336 individuals suffered a major cardiovascular event, 6% of the individuals in the vitamin D group and 6.6% of the individuals in the placebo group.
The major cardiovascular event rate was 9% lower in the vitamin D group in comparison to the placebo group (equal to 5.8 fewer major cardiovascular events per 1,000 individuals).
The coronary revascularization rate was 11% lower and the heart attack rate was 19% lower in the individuals in the vitamin D group with no difference seen in the stroke rate between the 2 groups.
Some indication of a more pronounced effect was seen in individuals who were making use of statins or other medications for cardiovascular disease at the beginning of the study, but these results weren’t statistically significant.
It was calculated overall that 172 individuals would need to take vitamin D supplements every month to prevent 1 major cardiovascular event.
It was acknowledged by the researchers that there might be a small cardiovascular event underestimate and the results might not apply to other population groups, especially groups where a higher proportion of individuals are deficient in vitamin D.
The researchers conclude that the results indicate that supplementing vitamin D could help reduce major cardiovascular event risk.
This protective effect may be more noticeable in individuals using statins or other cardiovascular medications at baseline.
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