Low Vitamin D Linked to Atherosclerosis, Study Finds

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Investigators have identified new evidence from the Northern Manhattan

Study connecting low vitamin D levels to atherosclerosis. They found that

low 25-hydroxyvitamin D levels were associated with increased intima-media

and maximal carotid thickness in those with plaque.

" Our report demonstrates an independent effect of low vitamin D on

subclinical indices of carotid atherosclerosis, " senior investigator Shonni

Silverberg, MD, from the Columbia University College of Physicians and

Surgeons in New York, told *Medscape Medical News*. " It is, however,

important to note that our observations do not provide insight into the

nature of the interaction of low vitamin D with the atherosclerotic

process. "

The work will be published in the August issue of *Stroke* but was released

early online <http://stroke.ahajournals.org/content/42/8/2240>.

The investigators studied 203 adults from the Northern Manhattan Study who

had serum measurements and carotid ultrasonography. They looked at

25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, phosphorus, and

parathyroid hormone.

After adjusting for cardiovascular risk factors, the researchers found that

plaque number was associated with phosphorus levels (beta, 0.39 per 1-mg/dL

increase; *P *= .02) and calcium-phosphorus product (beta, 0.36 per 10-U

increase; *P = *.03).

The majority of those studied — 57% — had plaque, and investigators found

the association of plaque number with phosphorus and calcium-phosphorus

product persisted.

*Vitamin D and Carotid Thickness*

They found that 25-hydroxyvitamin D was inversely associated with both

intima-media thickness (beta, -0.01 per 10-ng/mL increase; *P *= .05) and

maximal carotid plaque thickness (beta, -0.10 per 10-ng/mL increase; *P = *

..03).

In a model containing traditional cardiac risk factors and indices of

mineral metabolism, 25-hydroxyvitamin D accounted for 13% of the variance in

both intima-media thickness and maximal carotid plaque thickness. Calcium,

parathyroid hormone, and 1,25-dihydroxyvitamin D levels were not associated

with carotid measures.

" We confirmed prior data showing a relationship of carotid measures with

calcium-phosphorus product, " Dr. Silverberg said. " More importantly, we

found a robust association of vitamin D levels with subclinical markers of

carotid atherosclerosis. "

Dr. Silverberg pointed out that some of the prior literature in this area

did not adequately control for cardiovascular risk factors and renal

function, and most of the available data did not account for the interaction

of vitamin D with other indices of mineral metabolism.

Asked by *Medscape Medical News* to comment, Michal Melamed, MD, from the

Albert Einstein College of Medicine in New York, said she was glad the

authors looked at multiple bone minerals and not just vitamin D. " The sample

size was small, but it is encouraging they still found an association. "

*Limitations*

Dr. Melamed complimented the study but acknowledged that more work is

needed. " This is a nice study, but it is still cross-sectional. We cannot

establish a causal relationship and many questions remain regarding optimum

vitamin D levels. "

Dr. Melamed says she hopes some of these questions will be answered by

the VITAL

study <http://www.vitalstudy.org/>. Also known as the Vitamin D and Omega-3

Trial, the research study is designed to include 20,000 men and women across

the United States.

Investigators from Brigham and Women's Hospital and Harvard Medical School

in Boston, Massachusetts, are studying whether daily dietary supplements of

vitamin D3 or omega-3 fatty acids reduce the risk for developing heart

disease, stroke, and cancer in people who do not have a history of these

illnesses. Recruitment began in January 2010 and is continuing through 2011.

*This study was funded by the National Institutes of Health. Coauthor Dr.

Tatjana Rundek reports receiving speaking fees from Bristol-Myers Squibb.

The other authors have disclosed no relevant financial relationships.*

*Stroke*. 2011;42:2240-2245.

Abstract<http://stroke.ahajournals.org/content/42/8/2240>

--

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