Heart Disease Risk May Increase With Lack Of Vitamin D

Article Date: 08 Jan 2008 - 6:00 PST

The same vitamin D deficiency that can result in weak bones now has
been associated with an increased risk of cardiovascular disease,
Framingham Heart Study researchers report in Circulation: Journal of
the American Heart Association.

"Vitamin D deficiency is associated with increased cardiovascular
risk, above and beyond established cardiovascular risk factors," said
Thomas J. Wang, M.D., assistant professor of medicine at Harvard
Medical School in Boston, Mass. "The higher risk associated with
vitamin D deficiency was particularly evident among individuals with
high blood pressure."

In a study of 1,739 offspring from Framingham Heart Study participants
(average age 59, all Caucasian), researchers found that those with
blood levels of vitamin D below15 nanograms per milliliter (ng/mL) had
twice the risk of a cardiovascular event such as a heart attack, heart
failure or stroke in the next five years compared to those with higher
levels of vitamin D.

When researchers adjusted for traditional cardiovascular risk factors
such as high cholesterol, diabetes and high blood pressure, the risk
remained significant with a 62 percent higher risk of a cardiovascular
event in participants with low levels of vitamin D compared to those
with higher levels.

Researchers observed the highest rate of cardiovascular disease events
in subset analyses dividing 688 participants according to high blood
pressure status. After researchers adjusted for conventional
cardiovascular risk factors, participants with hypertension and a
vitamin D deficiency had about 2 times the risk of having a
cardiovascular disease event in five years.

Researchers also found an increase in cardiovascular risk with each
level of vitamin D deficiency.

"We found that people with low vitamin D levels had a higher rate of
cardiovascular events over the five-year follow-up period," Wang said.
"These results are intriguing and suggestive but need to be followed
up with further study."

Study participants had no prior cardiovascular disease and were tested
for vitamin D status and then followed for an average of 5.4 years.

The participants attended the offspring examinations between 1996 and
2001. Researchers obtained medical history, physical examinations and
laboratory assessments of vascular risk factors. They also obtained
medical records related to cardiovascular disease.

Overall, 28 percent of individuals had levels of vitamin D below15 ng/
mL and 9 percent had levels below10 ng/mL. Although levels above 30 ng/
mL are considered optimal for bone metabolism, only 10 percent of the
study sample had levels in this range, researchers said.

During follow-up:

* 120 participants developed a first cardiovascular event including
fatal and nonfatal coronary heart disease;

* 28 participants had fatal or nonfatal cerebrovascular events such as
nonhemorrhagic stroke;

* 19 participants were diagnosed with heart failure; and

* 8 had occurrences of claudication, fatigue in the legs during
activity.

"Low levels of vitamin D are highly prevalent in the United States,
especially in areas without much sunshine," Wang said. "Twenty to 30
percent of the population in many areas has moderate to severe vitamin
D deficiency."

Most of this is attributed to lack of sun exposure, pigmented skin
that prevents penetration of the sun's rays and inadequate dietary
intake of vitamin D enriched foods, researchers said.

"A growing body of evidence suggests that low levels of vitamin D may
adversely affect the cardiovascular system," Wang said. "Vitamin D
receptors have a broad tissue distribution that includes vascular
smooth muscle and endothelium, the inner lining of the body's vessels.
Our data raise the possibility that treating vitamin D deficiency, via
supplementation or lifestyle measures, could reduce cardiovascular
risk.

"What hasn't been proven yet is that vitamin D deficiency actually
causes increased risk of cardiovascular disease. This would require a
large randomized trial to show whether correcting the vitamin D
deficiency would result in a reduction in cardiovascular risk."

Therfore, Wang doesn't recommend physicians check for vitamin D
deficiency or that those with a known vitamin D deficiency be treated
to prevent heart disease at this time.

During the past decade, researchers have studied several other
vitamins that initially showed promise in reducing heart disease. But
the vitamins didn't reduce heart disease in subsequent large
randomized trials.

"On the flip side, just because other vitamins haven't succeeded
doesn't preclude the possibility of finding vitamins that might
prevent cardiovascular disease," Wang said. "This is always an area of
great interest. Vitamins are easy to administer and in general have
few toxic effects."

The American Heart Association recommends that healthy people get
adequate nutrients by eating a variety of foods in moderation, rather
than by taking supplements. Food sources of vitamin D include milk,
salmon, mackerel, sardines, cod liver oil and some fortified cereals.
Vitamin or mineral supplements aren't a substitute for a balanced,
nutritious diet that limits excess calories, saturated fat, trans fat,
sodium and dietary cholesterol. This dietary approach has been shown
to reduce coronary heart disease risk in healthy people and those with
coronary disease.

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Article adapted by Medical News Today from original press release.
----------------------------

Co-authors are: Michael J. Pencina, Ph.D.; Sarah L. Booth, Ph.D.; Paul
F. Jacques, D.Sc.; Erik Ingelsson, M.D., Ph.D.; Katherine Lanier,
B.S.; Emelia J. Benjamin, M.D.; Ralph B. D'Agostino, Ph.D.; Myles
Wolf, M.D.; and Ramachandran S. Vasan, M.D. The National Institute of
Health, U.S. Department of Agriculture and American Heart Association
funded the study.

Source: Karen Astle
American Heart Association

*  *  *
That last paragraph makes no sense.  The AHA does not recommend
supplements, but they do recommend fortified cereals and cod liver
oil?  Cod liver oil seems like a supplement to me.  There is no
difference between eating a fortified cereal and taking a pill.

Marilyn