Vitamin D Deficiency Increases Risk Of Death From Heart Failure

Low levels of Vitamin D may substantially increase the risk of death due to heart failure according to the results of a study conducted by Israeli researchers and published in the European Journal of Heart Failure in February. The study also found that regular vitamin D supplementation lowered the risk of heart failure by a third.

The researchers, based at the Heart Institute, Hadassah University Hospital, Israel, looked at data from 3,009 heart failure patients and 46 825 controls who were free of heart failure. The average follow-up period was 518 days. The researchers found that heart failure patients had a lower median level of serum 25(OH)D (a measure of vitamin D status) than the control group. 25(OH)D levels were 36.9 nmol/L in the heart failure group compared to 40.7 nmol/L in the control group. The percentage of patients who were deficient in vitamin D, defined as a level of 25(OH)D < 25nmol/L, was also higher in the heart failure group compared to the control group – 28% vs 22%.

The researchers found that vitamin D deficiency was a strong risk factor for death in the heart failure group with those deficient in the vitamin 52% more likely to die during the study. Heart failure patients who regularly took a Vitamin D supplement had a 32% reduced risk of death.

Factors associated with vitamin D deficiency in the study included high BMI, low exposure to sunlight, diabetes, female gender, and decreased calcium and haemoglobin levels.

The results suggest that increasing vitamin D levels, either through greater sunlight exposure or supplementation, may be an effective way to lower the risk of death in patients who are suffering from heart failure.

Previous studies have found increased death rates from heart failure in the winter months. While this pattern is though to be the result of very cold temperatures, even countries with warm winters tend to have higher rates of heart failure in winter months suggesting a possible role for vitamin D status, which tends to be lowest in winter, in the progression of heart failure. A 2008 study of Australian citizens for example found that mortality rates from heart failure were 23.5% higher in winter despite the relatively mild winters experienced in most parts of Australia.

Low vitamin D levels have also been linked to a poorer prognosis for some forms of cancer. Adequate levels of Vitamin D are important for women at risk for osteoporosis because calcitriol, the hormonally active form of vitamin D increases calcium absorption.

Optimal serum 25(OH)D levels for cardiovascular health are thought to be in the range of 100 nmol/L (40ng/mL). Around 10% of Americans are estimated to be deficient in vitamin D however the figure is much higher in countries at extreme latitudes. In New Zealand for example, an estimated 1 in 4 adults are deficient in vitamin D. The elderly, those with dark skin, obese people, and office workers are generally at the highest risk of vitamin D deficiency.