Stroke and coronary heart disease are the 2 most typical causes of worldwide death, with aging increasing the danger of each these events. Previous studies have indicated that vitamin D influences heart problems.

A recent BMJ study discusses the outcomes of a randomized control trial (RCT) to guage the dose-dependent effect of vitamin D supplementation on the incidence of major cardiovascular events in older adults.

Study: Vitamin D supplementation and major cardiovascular events: D-Health randomised controlled trial. Image Credit: R_Szatkowski / Shutterstock.com

Background

Inside the vascular system, many of the cells that express the vitamin D receptor also express 1α-hydroxylase and might convert 25-hydroxyvitamin D (25(OH)D) to calcitriol, the energetic type of vitamin D. Calcitriol has several necessary biological functions including inflammation reduction, inhibition of proliferation of vascular smooth muscle, and regulation of the renin-angiotensin-aldosterone system.

One meta-analysis of RCTs indicated that vitamin D supplementation was ineffective in stopping cardiovascular events. Nevertheless, this final result was contradicted by the Women’s Health Initiative Trial, which included women participants and a low dose of Vitamin D.

The D-Health Trial was launched to guage whether monthly vitamin D supplementation improves the health outcomes of older adults. Although a previous evaluation using the D-Health cohort reported that vitamin D supplementation didn’t reduce mortality as a result of heart problems or all-cause mortality, their effect on the incidence of major cardiovascular events was not determined.

In regards to the study

The present study used data from the D-Health Trial to analyze whether vitamin D supplementation in Australian adults over the age of 60 years influenced the incidence of major cardiovascular events.

The D-Health Trial is a double-blind, placebo-controlled RCT with two parallel arms. The D-Health Trial cohort included adults from all Australian states and territories, except the Northern Territory, who were between 60 and 84 years of age.

Participants with a history of hyperparathyroidism, hypercalcemia, kidney stones, sarcoidosis, osteomalacia, or were under supplemental vitamin D of above 500 IU, were excluded.

Computer-generated permuted block randomization was used to assign participants in a 1:1 ratio in two groups randomly. One group received 60,000 IU of vitamin D3 (cholecalciferol), while the others received placebo tablets. Each vitamin D3 and placebo tablets were an identical in appearance.

Yearly, the study participants got 12 tablets and asked to take one initially of every month. Each participant received this intervention for five years, starting February 2015 to February 2020.

At baseline, participants accomplished a questionnaire providing details about pre-existing health conditions, sociodemographic and lifestyle aspects, and dietary patterns. Cardiovascular events, including myocardial infarction, stroke, or coronary revascularisation, of the participants were also reported.

Study findings

A complete of 21,315 participants were eligible for the D-Health Trial. Some participants left the trial for private reasons, whereas others were removed for incomplete data.

Finally, 21,302 participants were considered,10,658 within the Vitamin D group and 10,644 within the placebo group. A complete of 866 candidates died before the completion of the study.

Around 80% of participants reported taking not less than 80% of the study tablets. The mean serum 25(OH)D concentration of the placebo and vitamin D group was 77 nmol/L and 115 nmol/L, respectively. Similar adversarial events were reported in each groups.

In the course of the follow-up period,1,336 major cardiovascular events were noted, including 6% and 6.6% of the vitamin D and placebo groups, respectively. This finding indicates a lower incidence of cardiovascular events, particularly myocardial infarction, and coronary revascularization, within the vitamin D group in comparison with the placebo group. 

Although individuals treated with statins or other cardiovascular drugs at baseline or those with higher vitamin D status had higher outcomes, these effects weren’t clinically significant. The effect of vitamin D on cardiovascular events was found to be independent of sex, age, or body mass index.

Conclusions

The extensive study cohort of over 21,000 participants is the important thing strength of this trial. High retention and adherence to the intervention are other benefits of this study.

The present study identified cardiovascular events and mortality outcomes using comprehensive data linked to population-based administrative data sources. Nevertheless, a marginal underestimation of cardiovascular events is feasible as a result of the shortage of personal hospital data, particularly from Tasmania and South Australia.

Despite this limitation, the study findings indicate that vitamin D supplementation in older adults might reduce the incidence of major cardiovascular events, particularly coronary revascularisation and myocardial infarction.