"It's likely that more than one-third of older adults now have vitamin D levels associated with higher risks of death and few have levels associated with optimum survival," said Adit Ginde, MD, MPH, an assistant professor at the University of Colorado Denver School of Medicine's Division of Emergency Medicine and lead author on the study. "Given the aging population and the simplicity of increasing a person's level of vitamin D, a small improvement in death rates could have a substantial impact on public health."

Older adults are at high risk for vitamin D deficiency because their skin has less exposure to the sun due to more limited outdoor activities as well as reduced ability to make vitamin D.

The study analyzed data from the Third National Health and Nutrition Examination Survey conducted by the National Center for Health Statistics. The research team analyzed vitamin D in blood samples of more than 3,400 participants that were selected to be representative of the 24 million older adults in the United States. Compared to those with optimal vitamin D status, those with low vitamin D levels were 3 times more likely to die from heart disease and 2.5 times more likely to die from any cause.

Dr. Ginde says the findings suggest that current daily recommendations of vitamin D may not be enough for older adults to maintain optimal health. The research team has applied for research funding from the National Institutes of Health to perform a large, population-based clinical trial of vitamin D supplementation in older adults to see if it can improve survival and reduce the incidence of heart disease.

"Confirmation of these results in large randomized trials is critically important for advancing public health," says Carlos Camargo, MD, DrPH, of the MGH Department of Emergency Medicine, the senior author of the study and an associate professor of medicine at Harvard Medical School.

The study looking at elderly death rates is the second of two studies by the same team of researchers on vitamin D and general health. The first study, published in Archives of Internal Medicine earlier this year, identified vitamin D as playing a significant role in boosting the immune system and warding off colds and flu.

"Vitamin D has health effects that go beyond strong bones," says Ginde. "It's likely that it makes a vital contribution to good health."

Note: If no author is given, the source is cited instead.

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