In the newest in a line of studies showing the potential value of vitamin D, new research from Johns Hopkins University shows that not getting enough of the so-called "sunshine vitamin" may increase the risk of early death by more than a quarter.
Researchers used data from the Third National Health and Nutrition Examination Survey and looked at people's vitamin D levels and then death from various causes. While the risk of death for people with low vitamin D from any single cause was only slightly elevated, the broader picture showed a 26 percent increase in death rates.
"[Low] vitamin D levels seem to confer an increased risk of dying from any cause," said Dr. Erin Michos, a cardiologist at Johns Hopkins, and one of the lead investigators of the study.
She said that the study showed an association between low vitamin D and death from heart disease, and said further study may reveal vitamin D to be a sign of impending heart disease.
"We think we have additional evidence to consider adding vitamin D deficiency as a distinct and separate risk factor for death from cardiovascular disease, putting it alongside much better known and understood risk factors, such as age, gender, family history, smoking, high blood cholesterol levels, high blood pressure, lack of exercise, obesity and diabetes," Michos said.
The study was published in this week's issue of the Archives of Internal Medicine.
But the study's researchers and others were quick to say that the study provides absolutely no evidence for now that taking vitamin D can reduce the risk of heart disease.
"Before we tell all Americans out there that this will definitely prevent heart attack, we need some clinical trials," Michos said.
Some took it a step further and questioned whether low vitamin D levels can even be considered a risk factor at all at this point.
"A relative increase in risk of death of 26 percent is not trivial, but not huge, either," said Dr. David Katz, director of the prevention research center at Yale University School of Medicine.
"Consider that being physically active, not smoking, and eating well could reduce the risk of premature death by as much as 80 percent," said Katz. "We would not want people to get the impression that a vitamin D supplement is a panacea. The findings are by no means that significant."
Others strongly agreed.
"It can't be considered a risk factor with the strength of cholesterol and hypertension until further studies are done," said Dr. Melvyn Rubenfire, the director of preventive cardiology at the University of Michigan.
But Rubenfire did not dismiss the importance of adequate vitamin D intake.
"I do encourage patients with CAD and other risk factors to be sure they have both adequate calcium and vitamin D, particularly those that use sun block," he said.
In fact, use of sunscreen in response to concerns about melanoma was cited by a number of physicians as a reason why many Americans are below advisable levels of vitamin D.
"I have been checking vitamin D studies in my patients for the last year and a half, and I have been astounded by the number of patients [with healthy lifestyles] that are 'D'- deficient," said Dr. Sandra Fryhofer, a clinical associate professor of medicine at Emory University School of Medicine.