Adequate vitamin D levels appeared to be protective against the risk of death during a 67.5-month average follow-up period among men and women with congestive heart failure. Conversely, high magnesium depletion scores (indicating a high risk of having low magnesium levels) increased mortality risk. Individuals with both low vitamin D plus high magnesium depletion scores had more than double the risk of mortality from all causes compared with those who had adequate vitamin D and low magnesium depletion scores.

The study included 1,022 individuals with congestive heart failure who participated in the National Health and Nutrition Examination Survey (NHANES) 2007-2018. Blood samples were analyzed for serum vitamin D levels that were categorized as adequate at 20 ng/mL or more, or deficient at less than 20 ng/mL. Magnesium depletion was scored according to the presence of treatment with diuretic drugs, proton pump inhibitor use (which inhibits stomach acid), low estimated glomerular filtration rate (eGFR, a marker of kidney function) and heavy drinking. The men and women were followed for an average of 67.53 months, during which 418 deaths occurred.

Adequate serum vitamin D levels were associated with a 22% lower adjusted risk of dying from all causes during follow-up in comparison with lower levels. For men and women with high magnesium depletion scores, the adjusted mortality risk was 72% greater than low scores. Similar variations in risk were revealed when mortality caused by cardiovascular disease was evaluated. When the effect of having both low vitamin D and high magnesium depletion scores was examined, the adjusted risk of mortality during follow-up was more than twice as great as that of individuals with adequate vitamin D and low magnesium depletion scores. Again, results were similar when cardiovascular disease mortality risk was analyzed.

The findings were reported in the November 2024 issue of the journal Magnesium Research.¹