When patients with a vitamin D (Vit-D) deficiency and no prior history of myocardial infarction (MI) are treated to a Vit-D level of >20 ng/mL, it is associated with a significantly lower risk of MI and all-cause mortality.
That lower MI risk, however, is only seen when patients maintain 25-hydroxyvitamin D, or (25-OH)D, levels of ≥30 ng/mL.
These findings, published in the Journal of the Endocrine Society, included data from 20,025 patients receiving treatment from 1999 to 2018. All patients had a Vit-D deficiency and no prior history of MI. All data came from the Veterans Health Administration.
The authors explained that the goal of the study was to examine the association of Vit-D with MI and all-cause mortality among different subpopulations of treated and untreated patients. When reviewing prior research, they noted that some studies did not appear to line up with others.
“There are conflicting data related to low Vit-D level and all-cause mortality," wrote lead author Prakash Acharya, MD, department of cardiovascular medicine at the University of Kansas Medical Center, and colleagues. "Our study appears to unify and provide an explanation for some of the contradictory data related to Vit-D and its association with MI and all-cause mortality.”
Patients in the team's study were separated into three groups:
- Group A remained untreated and had Vit-D levels ≤20 ng/mL
- Group B was treated to Vit-D levels of 21-29 ng/mL
- Group C was treated to Vit-D levels ≥30 ng/mL.
The authors found that risk of MI was significantly lower in Group C than in Group B and Group A. There was no difference in the risk of MI between Group B and Group A, however.
Compared with Group A, both Group B and Group C had a much lower risk of all-cause mortality. There was no difference in the risk of all-cause mortality between Group B and Group C.
“In the future, adequately powered, prospective, well-designed trials with a long-term follow-up will be needed to reach a conclusive agreement regarding the effect of Vit-D supplementation, and post-supplement (25-OH)D target levels on MI risk,” the authors wrote.
The full study can be read here.