Low vitamin D shown to raise death risk: U.S. study
Reported August 11, 2008
CHICAGO (Reuters) – Adults with a vitamin D deficiency are more likely to die than those with high levels, another indication of the nutrient’s vital role in guarding against ailments from heart disease to cancer, U.S. researchers said on Monday.
The report follows several recent studies that have shown vitamin D may protect against ailments including heart disease, cancers of the colon and breast, diabetes and tuberculosis.
Those with the lowest levels of the “sunshine vitamin” had a 26 percent increased risk of death over eight years compared to those with the highest levels, the researchers reported in the Archives of Internal Medicine.
Dr. Erin Michos of Johns Hopkins University in Baltimore and colleagues including Dr. Michal Melamed, who is now at the Albert Einstein College of Medicine in New York, studied 13,331 adults for an average of 8.7 years.
Of the 1,806 people who died, 777 died of heart disease. Vitamin D deficiency was also linked to a higher risk of death from cancer, diabetes and other diseases.
“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 in a statement.
Scientists have evidence that Vitamin D helps lower blood pressure, reduce inflammation and boost the immune system.
“The fact that all the deaths went up, but we could not find the specific cause, may be because vitamin D plays a role in both cancer and heart disease and potentially other things” like diabetes, Melamed said in a telephone interview.
Vitamin D deficiency is common: about one-quarter of U.S. adults have less than the 18 nanograms per milliliter of blood Melamed recommended as minimal. About two in five American men and half of women have less than the 28 nanograms per milliliter considered healthy.
The body makes vitamin D when skin is exposed to sunlight, and it is also found in fatty fish like salmon. But many people get too little, especially in winter. The vitamin is added to milk and other foods in many countries.
But too-high levels were also found to be harmful, Melamed said, although not as harmful as deficiency.
How vitamin D works on the molecular level is unclear, but it can improve bone health by helping absorb calcium. Receptors for the vitamin have been found on the pancreatic cells that produce insulin.
“It’s amazing the things that vitamin D has been associated with. I think part of that may be that it’s used as a messenger system, it’s a hormone in the body, and once the body finds a good messenger system, it uses it for a lot of different things,” Melamed said.