Vitamin D supplementation reduces risk of major cardiovascular

Vitamin D supplementation reduces the risk of major cardiovascular events in older adults

The two leading causes of death worldwide are coronary heart disease and stroke, with aging raising the risk of both of these conditions. According to earlier research, vitamin D affects cardiovascular disease.

The findings of a recent randomized control trial (RCT) to assess the dose-dependent effect of vitamin D supplementation on the frequency of major cardiovascular events in older persons are discussed in the British Medical Journal.

Background

Most cells that exhibit the vitamin D receptor in the circulatory system also express the enzyme 1 hydroxylase, which can change 25-hydroxyvitamin D (25(OH)D) into calcitriol, the active form of vitamin D. Inhibiting the growth of vascular smooth muscle, reducing inflammation, and controlling the renin-angiotensin-aldosterone system are only a few of the significant biological effects of calcitriol.

Vitamin D supplementation was found unsuccessful in avoiding cardiovascular events, according to one meta-analysis of RCTs. The Women’s Health Initiative Trial, which comprised women participants with a modest dose of Vitamin D, however, refuted this finding.

The D-Health Trial was started to determine whether monthly vitamin D supplementation enhances older persons’ health outcomes. The incidence of significant cardiovascular events was not studied, despite the fact that prior research utilizing the D-Health cohort found that vitamin D treatment did not lower death from cardiovascular disease or all causes.

About the study

The current investigation examined whether vitamin D supplementation in Australian individuals over 60 years of age affected the risk of major cardiovascular events using data from the D-Health Trial.

The D-Health Trial is a parallel-arm, double-blind, placebo-controlled RCT. Adults aged 60 to 84 from all Australian states and territories, excluding the Northern Territory, were included in the D-Health Trial cohort. Excluded from the study were participants who had a history of hyperparathyroidism, hypercalcemia, kidney stones, sarcoidosis, or osteomalacia, or who were taking more than 500 IU of supplemental vitamin D.

Participants were randomized and divided into two groups in a 1:1 ratio using computer-generated permuted block randomization. 60,000 IU of vitamin D3 (cholecalciferol) was given to one group, while placebo tablets were given to the others. The placebo and vitamin D3 tablets had the same design.

Twelve tablets were sent to the study subjects each year, and they were instructed to take one at the start of each month. The duration of this intervention for each participant was five years, from February 2015 to February 2020.

Participants filled out a questionnaire on their baseline food habits, sociodemographic and lifestyle characteristics, and pre-existing medical issues. The participants’ cardiovascular events, such as myocardial infarction, strokes, or coronary revascularization, were also reported.

 

Study Findings

For the D-Health Trial, a total of 21,315 participants were qualified. Some trial subjects quit for private reasons, while others were dropped due to insufficient data.

Finally, 21,302 subjects were considered, with 10,658 receiving vitamin D and 10,644 receiving a placebo. 866 applicants in total passed away before the study was finished.

A little more than 80% of individuals said they had taken at least 80% of the study pills. The placebo group’s mean serum 25(OH)D concentration was 77 nmol/L, while the vitamin D group’s mean concentration was 115 nmol/L. Both groups reported experiencing comparable negative outcomes.

1,336 significant cardiovascular events were reported over the follow-up period, with the vitamin D and placebo groups experiencing 6% and 6.6% of these events, respectively. This finding suggests that the vitamin D group had a reduced incidence of cardiovascular events than the placebo group, notably myocardial infarction, and coronary revascularization.

Although those with higher vitamin D status or those treated with statins or other cardiovascular medicines at baseline had better outcomes, these effects were not clinically significant. The effect of vitamin D on cardiovascular events was independent of sex, age, or body mass index.

Conclusions

The main advantage of this experiment is the sizable research cohort, which includes more than 21,000 people. Other benefits of this study include high retention and adherence to the intervention.

The current study used extensive data connected to population-based administrative data sources to identify cardiovascular events and mortality outcomes. However, a little underestimating of cardiovascular events is conceivable due to a paucity of private hospital data, particularly from Tasmania and South Australia.

Despite this drawback, the results of the study suggest that older persons who use vitamin D supplements may see a reduction in the frequency of serious cardiovascular events, including coronary revascularization and myocardial infarction.

Journal reference:
  • Thompson, B., Waterhouse, M., English, D. R., et al. (2023) Vitamin D supplementation and major cardiovascular events: D-Health randomized controlled trial. BMJ, 381. doi:10.1136/bmj-2023-075230

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