Table 2.

Important Trials of Vitamin D Supplementation on Cardiovascular Outcomes

Study	Population	Intervention vs . control	Baseline 25-OHD level	Duration	Outcome	Comments
Scragg et al. (2017) (ViDA trial) [79]	New Zealand	200,000 IU of vitamin D3 followed a month later by monthly doses of 100,000 IU	25.3±9.5 ng/mL	3.3 years	Incident CVD and death: HR, 1.02; 95% CI, 0.87–1.2	Primary outcome
	n=5,110					High retention rate (87%)
	Mean age 65.9 years					High adherence (84%)
	Female and male	Placebo				Short duration of followup, low event rate
Manson et al. (2019) (VITAL trial) [81]	United States	2,000 IU daily of cholecalciferol	30.8±10 ng/mL	5.3 years	Composite outcome of major cardiovascular events (MI, stroke, and cardiovascular death): HR, 0.97; 95% CI, 0.85–1.12	Primary outcome
	n=25,871					Large sample size
	Female (≥55 years)	Placebo				Multiethnic
	Male (≥50 years)					High rate of adherence
						High rate of follow-up
Neale et al. (2022) (D-health Trial) [82]	Australian	60,000 IU monthly of cholecalciferol	Not measured	5 years	All-cause mortality: HR, 1.04; 95% CI, 0.93–1.18	All-cause mortality was the primary outcome
	n=21,315		Predicted level (ng/mL):
	≥60 years	Placebo	Intervention arm: ≥20 (76%)		Cardiovascular mortality: HR, 0.96; 95% CI, 0.72–1.28	Cause specific mortality was not prespecified in the protocol
	Men and women		Placebo arm: ≥20 (75.2%)

25-OHD, 25-hydroxyvitamin D; ViDA, Vitamin D Assessment Study; IU, international unit; CVD, cardiovascular disease; HR, hazard ratio; CI, confidence interval; VITAL, VITamin D and OmegA-3 TriaL; MI, myocardial infarction.