WEDNESDAY, April 16 (HealthDay News) -- New research has
discovered that people with low blood levels of vitamin D were
found to have a higher incidence of peripheral arterial disease
(PAD), potentially dangerous blockages in the leg arteries.
The study of nearly 4,900 American adults found more than double
the incidence of PAD among those with the lowest levels of vitamin
D compared to those with the highest levels.
The finding was presented Wednesday at the American Heart
Association's Arteriosclerosis, Thrombosis and Vascular Biology
annual conference, in Atlanta.
One previous study found an association between low vitamin D
levels and heart disease, said study author Dr. Michal Melamed, an
assistant professor of medicine, epidemiology and population health
at Albert Einstein College of Medicine in New York City.
"But in that study they found only eight cases of PAD," she
said. "In our analysis, we have more than 400 people with PAD."
Vitamin D is made when the body is exposed to sunlight. It is
converted to a hormone that makes bones stronger. A severe
deficiency can cause rickets in children. The link to blood vessel
problems has emerged in recent years.
"The underlying mechanism isn't quite known," Melamed said. "But
the study definitely speaks to the fact that it is an association
that needs to be further explored."
Current guidelines recommend a vitamin D intake of 400
International Units a day for people aged 50 and older. In addition
to sunlight, other sources of the vitamin are salmon, sardines, cod
liver oil, fortified milk and some fortified cereals.
Exposure to sunlight "always calls for a balance," Melamed said,
because overexposure raises the risk of skin cancer. "I would
recommend about 10 to 15 minutes of direct exposure, then putting
on sun block," she said.
Supplements aren't recommended by Dr. Thomas J. Wang, an
assistant professor of medicine at Harvard Medical School and
Massachusetts General Hospital, who led the earlier study.
"There have been a number of very intriguing population
findings, but we still don't know if supplementation will affect
the risk of cardiovascular disease," Wang said. "A clinical trial
would be needed to see if supplementation could avert risk. We know
that the things to prevent vitamin D deficiency include sunlight
and proper diet."
But Dr. Denise Teves, an endocrinologist who is an assistant
professor of medicine at the Medical College of Wisconsin, said a
case could be made for vitamin D supplements for some people.
"I recommend supplements for some patients who come to me with
metabolic bone disease," she said. "Most have insufficient vitamin
D."
Existing guidelines might fall short of what is needed for some
people, Teves said.
"The current guidelines do call for 400 units a day," she said.
"But in the last two or three years, many endocrinologists have
been recommending at least 800 units a day. I have seen many
students in Wisconsin in the wintertime with low vitamin D
levels."
It's best to consult a doctor about taking large amounts of a
vitamin D supplement, Teves said.
More information
A fact sheet on vitamin D is available from the
U.S. Office of Dietary Supplements.
