Can vitamin D levels affect mortality rates in heart attack survivors?

This study looked at the effect of vitamin D levels on mortality rates in patients who have survived a heart attack. The authors concluded that overly low or high levels of vitamin D significantly increased the risk of mortality in patients who have survived a heart attack.

When a coronary artery (the blood vessels that supply blood to the heart) suddenly becomes blocked this can lead to acute myocardial infarction, commonly known as a heart attack. Studies have shown that vitamin D levels in the blood are lower in patients who have survived a heart attack. This may be associated with an increased risk of mortality. While supplementing patients with vitamin D may help to lower this risk, it is not clear if excessively high levels of vitamin D would be helpful or harmful for these patients. 

This study included 477 patients who have experienced an acute myocardial infarction. Patients were assigned to different groups based on the vitamin D levels in their blood. 162 patients had very low levels of vitamin D (less than 10 ng/ml). 162 patients had low levels (between 10 and 20 ng/ml). 106 patients had normal levels (between 20 and 30 ng/ml). 47 patients had high levels of vitamin D (over 30 ng/ml). Mortality rates were recorded over an average period of 57 months.

20% of patients died during the study follow-up. Extreme values of vitamin D (less than 10 or higher than 30 ng/ml) were found to be independent predictors of mortality. Overall, the mortality risk was increased 3.02-fold for patients with very low or high vitamin D levels in their blood. Older age, severity of heart failure, and previous treatment with ACE inhibitors or statins also increased the risk of mortality.

The authors concluded that excessively low or high levels of vitamin D can increase the risk of mortality in patients with acute myocardial infarction.

Vitamin D levels in patients were only measured at the beginning of the study and may have changed over time.