Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Vitamin D levels have different effects on atherosclerosis in blacks and whites

15.03.2010
Vitamin D is quickly becoming the "go-to" remedy for treating a wide range of illnesses, from osteoporosis to atherosclerosis. However, new evidence from a Wake Forest University School of Medicine study suggests that supplementing vitamin D in those with low levels may have different effects based on patient race and, in black individuals, the supplement could actually do harm.

The study is the first to show a positive relationship between calcified plaque in large arteries, a measure of atherosclerosis or "hardening of the arteries," and circulating vitamin D levels in black patients. It appears in the March issue of the Journal of Clinical Endocrinology and Metabolism.

"In black patients, lower levels of vitamin D may not signify deficiency to the same extent as in whites," said the study's lead investigator, Barry I. Freedman, M.D., John H. Felts III Professor and chief of the section on nephrology at the School of Medicine "We should use caution when supplementing vitamin D in black patients while we investigate if we are actually worsening calcium deposition in the arteries with treatment."

Vitamin D is widely used to treat patients with osteoporosis and/or low vitamin D levels based on a medically accepted normal range. This "normal" range is typically applied to all race groups, although it was established predominantly in whites. It is thought that as low vitamin D levels rise to the normal range with supplementation, protection from bone and heart disease (atherosclerosis) may increase, as well.

Blacks generally have lower vitamin D levels than whites, partly because their darker skin pigmentation limits the amount of the vitamin produced by sunlight. Blacks also consume fewer dairy products and ingest less dietary calcium than whites, said Freedman, an affiliate of the Maya Angelou Center for Health Equity, part of the School of Medicine. Despite these lower vitamin D levels and dietary calcium ingestion, blacks naturally experience lower rates of osteoporosis and have far less calcium in their arteries. Studies further reveal that black patients with diabetes have half the rate of heart attack as whites, when provided equal access to health care. This shows that lower levels of calcified atherosclerotic plaque in blacks are associated with a lower risk of heart disease. However, blacks in the general community have higher rates of heart attack than whites, potentially due to unequal access to medical care, Freedman said.

The research team determined the relationship between circulating vitamin D levels and arterial calcium in 340 black men and women with type 2 diabetes. Calcium can deposit in blood vessel walls forming a bone-like material called "calcified atherosclerotic plaque" and this plaque can be detected by computed tomography (CT) scans. Calcified atherosclerotic plaque is a reliable predictor of risk for heart attack and stroke. The investigators measured vitamin D levels in all study participants and then performed a CT scan to detect calcium in the heart and major arteries.

"We found that higher circulating levels of vitamin D in blacks were associated with more calcium in the artery walls," Freedman said. "This is the opposite effect of what is felt to occur in white patients and shows that the accepted "normal" range of vitamin D may be different between blacks and whites.

"Many of these study patients would be placed on supplemental vitamin D by their physicians simply because their levels were felt to be in the low range." Freedman added that physicians should use caution in supplementing vitamin D levels in blacks – especially if they do not have weak bones or other reasons to take this vitamin – until the effects of supplementing vitamin D on blood vessels and heart disease are better understood.

"Doctors frequently prescribe supplemental vitamin D," Freedman said. "However, we do not know all of its effects and how they may differ between the races. The bottom line is that racial differences in calcium handling are seen and black and white patients have differing risk for bone and heart disease. We should more clearly determine the effects of supplementing vitamin D in black patients with low levels based on existing criteria and should not assume that the effects of supplementation will be the same between the races."

Co-authors of the study, which was funded by the National Institutes of Health, were Lynne E. Wagenknecht, Dr.P.H., Kristen G. Hairston, M.D., Donald W. Bowden, Ph.D., J. Jeffrey Carr, M.D., R. Caresse Hightower, Ethel J. Gordon, Jianzhao Xu, Carl D. Langefeld, Ph.D., and Jasmin Divers, Ph.D., all of the School of Medicine.

Media Relations Contacts: Jessica Guenzel, jguenzel@wfubmc.edu, (336) 716-3487; or Bonnie Davis, bdavis@wfubmc.edu, (336) 716-4977.

Wake Forest University Baptist Medical Center (www.wfubmc.edu) is an academic health system comprised of North Carolina Baptist Hospital, Brenner Children's Hospital, Wake Forest University Physicians, and Wake Forest University Health Sciences, which operates the university's School of Medicine and Piedmont Triad Research Park. The system comprises 1,056 acute care, rehabilitation and long-term care beds and has been ranked as one of "America's Best Hospitals" by U.S. News & World Report since 1993. Wake Forest Baptist is ranked 32nd in the nation by America's Top Doctors for the number of its doctors considered best by their peers. The institution ranks in the top third in funding by the National Institutes of Health and fourth in the Southeast in revenues from its licensed intellectual property.

Jessica Guenzel | EurekAlert!
Further information:
http://www.wfubmc.edu

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>