5MinuteConsult Journal Club

Vitamin D Supplementation May Lower MI Risk and All-Cause Mortality

Reference

J of Endocrine Society 2021; 5(10): https://doi.org/10.1210/jendso/bvab124

Study Summary

Retrospective case control study of > 20,000 US Veterans with Vitamin D Deficiency and no prior myocardial infarction history to evaluate the potential benefit of vitamin D replacement on outcomes.  3 groups were considered: those with levels < 20 ng/ml and untreated, those who were treated to a level between 21-29 ng/ml and those treated to >/= 30 ng/ml.  After review from 1999-2018, those who were treated to a 25 OH level > 30 ng/ml had lower rates of MI and All-Cause Mortality. 

Conclusion  

For Vitamin D Deficient patients, supplementation to a 25-OH level of > 30 ng/ml may lower MI and All-Cause Mortality benefit.

Discussion  

This has been studied in randomized trials in the past, and evaluated by meta-analysis, with conclusions of there being no benefit to Vitamin D replacement.  Dr. Barua, the senior author on this paper, states the reason for this difference is this study looked at Vitamin D deficient patients, whereas the previous RCT’s included patients who already had levels > 30 ng/ml at the time of randomization.  He also states most previous trials have been for much shorter time periods, implying the benefits of Vitamin D replacement in those who are deficient may take much longer.

This type of study is open to a variety of potential biases, namely being in the VA system may have had altered how they were treated compared to those outside of that system.  But, as the risks of screening and treating Vitamin D deficiency are only the minimal cost, and the potential benefit a reduction in two very hard endpoints (MI, Death), offering either screening and supplementation OR just supplementation (if testing is not covered) seems extremely reasonable.  Most patients can take 2-4,000 IU of Vitamin D per day without risk of toxicity.

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