Association of low vitamin D levels with risk of CHD events differs by race, ethnicity

EurekAlert! ^ | July 9, 2013 | NA

[neverdem]

In a multiethnic group of adults, low serum 25-hydroxyvitamin D concentration was associated with increased risk of coronary heart disease events among white or Chinese participants but not among black or Hispanic participants, results that suggest that the risks and benefits of vitamin D supplementation should be evaluated carefully across race and ethnicity, according to a study in the July 10 issue of JAMA.

"Low circulating concentrations of 25-hydroxyvitamin D (25[OH]D) have been consistently associated with increased risk of clinical and subclinical coronary heart disease (CHD). Whether this relationship is causal and modifiable with vitamin D supplementation has not yet been determined in well-powered clinical trials, which are ongoing," according to background information in the article. "Most studies of 25(OH)D and risk of CHD have examined populations that are composed largely or entirely of white participants. Results from these studies are frequently extrapolated to multiracial populations. This may not be appropriate because vitamin D metabolism and circulating 25 (OH)D concentrations vary substantially by race/ethnicity."

Cassianne Robinson-Cohen, Ph.D., of the University of Washington, Seattle, and colleagues examined the association of serum 25(OH)D concentration with incident CHD events in a large, community-based, multiethnic population of adults. The analysis included 6,436 participants in the Multi-Ethnic Study of Atherosclerosis (MESA), recruited from July 2000 through September 2002, who were free of known cardiovascular disease at the beginning of the study. Serum 25(OH)D concentrations were measured at baseline and associations of 25(OH)D with adjudicated CHD events were assessed through May 2012. Adjudicated CHD event was defined as myocardial infarction (heart attack), angina, cardiac arrest, or CHD death.

At the beginning of the study, the average age was 62 years and 53 percent of participants were women. Average serum 25(OH)D concentrations varied substantially by race/ethnicity. During a median (midpoint) follow-up of 8.5 years, 361 participants had a CHD event.

The researchers found significant heterogeneity in the association of 25(OH)D with CHD risk by race/ethnicity. Lower serum 25(OH)D concentration was associated with significantly higher risks of CHD among white participants (26 percent higher risk) per 10 ng/mL decrement in 25(OH)D concentration and Chinese participants (67 percent higher risk). "However, there was no evidence of association among black participants or Hispanic participants."

"Differences in associations across race/ethnicity groups were consistent for both a broad and restricted definition of CHD and persisted after adjustment for known CHD risk factors," the authors write.

"Well-powered clinical trials are needed to determine whether vitamin D supplements have causal and clinically relevant effects on the risk of CHD. Currently, at least 5 such trials are under way. One of these trials, the Vitamin D and Omega-3 Trial (VITAL), is targeting enrollment of a large multiracial study population, although power may be insufficient to determine whether effects vary by race even in this trial. Our study suggests that the risks and benefits of vitamin D supplementation should be evaluated carefully across race and ethnicity, and that the results of ongoing vitamin D clinical trials should be applied cautiously to individuals who are not white."

(JAMA. 2013;310(2):179-188; Available pre-embargo to the media at http://media.jamanetwork.com)

Editor's Note: This study was supported by grants from the National Heart, Lung, and Blood Institute. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, etc.

Editorial: Race/Ethnicity, Serum 25-Hydroxyvitamin D, and Heart Disease

In an accompanying editorial, Keith C. Norris, M.D., of the University of California, Los Angeles, and Sandra F. Williams, D.M.D., M.D., of the Cleveland Clinic, Weston, Fla., write that "… this large, well-designed, multiethnic study adds important insights to the complex relationships among race/ethnicity, 25(OH)D concentrations, and CHD risk."

"The heterogeneity of the findings underscores the importance of exploring racial differences in clinical research and of not immediately generalizing results from ethnically homogeneous populations to other groups that may differ by race/ethnicity, sex, or age. Although the pooled data demonstrated a significant association between 25(OH)D and CHD, the subgroup analyses revealed marked differences underscoring the importance of examining such cohorts by race/ethnicity and thereby potentially discovering sociocultural or biological mediators that may affect cardiovascular health."

(JAMA. 2013;310(2):153-154; Available pre-embargo to the media at http://media.jamanetwork.com)

Editor's Note: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr. Norris reports receiving grant support from the National Institutes of Health; and payment for lectures and consulting from Abbott, Amgen, Davita, and Takeda. Dr. Williams reported no disclosures.

###

[neverdem]

Vitamin D is racist. Who knew?

Racial Differences in the Association of Serum 25-Hydroxyvitamin D Concentration With Coronary Heart Disease Events

I could only find the first page of the editorial.

Here are some references from the second page:

Relationship of Vitamin D and Parathyroid Hormone to Obesity and Body Composition in African Americans FReebie

Vitamin D and Hypertension - Current Evidence and Future Directions FReebie

Back to the future: a new look at ‘old’ vitamin D FReebie

Could gaia be racist? African Americans have the highest levels of parathyroid hormone acccording to the first FReebie, and white devils usually have a different vitamin D binding protein according to the last FReebie, so sayeth the second page of the accompanying editorial.

There was also that story in Family Practice News which stated that blacks getting vitamin D supplements were more likely to get calcified arteries.

[presently no screen name]

Interesting. It sure seems ‘racist’ and could be a bummer for those children of mixed white and black race the most, I would think.

What number are they using as a baseline for Vit D? I have heard ‘30’ is good and I heard ‘50’ is ideal.

[jespasinthru]

Why was this study even necessary? The human body absorbs vitamin D from the sun. The more pigment in the skin, the more vitamin D can be absorbed. You learn that in high school biology class.

[meatloaf]

Low vitamin D levels are prevalent today especially in the winter. Why do think people catch the flu in the winter “flu season.”

[Mamzelle]

How about a simple summary when a densely composed article like this us posted?

[Wilum]

The Mohawk Valley in upstate NY is considered a “low Vitamin D area” because of cloud cover 75% of the year according to my Dr. I am on 2000IU a day as my level was in the very low 20’s. I spend allot of time outdoors and apparently she was right.

[windcliff]

ping

[onedoug]

“Right. Doctor....” —George Costanza

[Black Agnes]

BP/health outcomes ping.

[neverdem]

How about a simple summary when a densely composed article like this us posted?

The serum 25-hydroxyvitamin D concentration is how vitamin D is measured in blood. There was an inverse relation between serum 25-hydroxyvitamin D concentration and the "risk of coronary heart disease events among white or Chinese participants but not among black or Hispanic participants,..."

Coronary heart disease, CHD, is also called coronary artery disease, CAD. Coronary arteries have a few main underlying pathologies, but they usually become evident with "myocardial infarction (heart attack), angina, cardiac arrest, or CHD death."

The latter two are best diagnosed by autopsy, also known as a post mortem.

A myocardial infarction can be diagnosed by specific electrocardiogram changes, i.e. what are called Q waves for prior myocardial infarctions or S-T segment elevations for a myocardial infarction in progress. An ongoing or recent myocardial infarction is also evident by specific cardiac enzymes in the blood which are not normal.

Angina is a clinical diagnosis made by history. Stable angina is diagnosed when the patient reports that a specific amount of exercise, e.g. walking so many blocks, causes reproducible chest pain or shortness of breath or both. Unstable angina is when the patient reports a sudden decrease in the exercise that they can tolerate.

[Wonder Warthog]

"Why was this study even necessary? The human body absorbs vitamin D from the sun. The more pigment in the skin, the more vitamin D can be absorbed. You learn that in high school biology class."

Modern humans rarely get enough sunlight. Our evolutionary ancestors were in the sun virtually all day, and most of that was in "high sunlight" areas (equatorial Africa, Middle East, etc.).

Current RDA's are a joke. My levels were in the low 20's, and I was plagued by cold after cold after cold, many of which developed into sinus infections requiring antibiotics.. I kept increasing dosage up to 5000IU/day and barely got it into the high 20's-very low 30's.

Then my wife changed the caplets she had been getting to ones 2X strength and neglected to inform me of the difference....so I was now taking 10,000IU/day. Haven't had a cold since. Next blood test showed levels in the low 50's. Needless to say I did NOT decrease dosage.

[neverdem]

What number are they using as a baseline for Vit D? I have heard ‘30’ is good and I heard ‘50’ is ideal.

You hav to look at the lab report, or get the doc to specify the units. Here's an excerpt:

How is Vitamin D Measured in the Body?

Serum 25-hydroxyvitamin D levels can be reported either as nanograms per milliliter (ng/ml) or as n[ano]moles per liter (nmol/L).

Don’t be confused if you see the value either way.

The current definitions of levels of vitamin D are:

Deficient: Less than or equal to 10 ng/ml (25 nmol/L)

Insufficient: Between 10 ng/ml and 20 ng/ml (25 to 50 nmol/L)

Sufficient: More than 20 ng/ml (50 nmol/L)

N.B. Vitamin D For Dummies Alan L. Rubin, MD ISBN: 978-0-470-89175-9 Paperback 288 pages June 2011

[presently no screen name]

THANK YOU!!

[presently no screen name]

Current RDA's are a joke.

I agree.

So it wasn't a prescription for D - the 2x was over the counter?

[AppyPappy]

I’m doing 1000mg now, down from 5000 mg. But I have started on Niacin.

[neverdem]

I’m doing 1000mg now, down from 5000 mg. But I have started on Niacin.

Look at the label for your vitamin D supplements. It's probably IU for international units. not milligrams, mg.

[1010RD]

The current definitions of levels of vitamin D are:

Deficient: Less than or equal to 10 ng/ml (25 nmol/L)

Insufficient: Between 10 ng/ml and 20 ng/ml (25 to 50 nmol/L)

Sufficient: More than 20 ng/ml (50 nmol/L)
+++++++++++++++++++++++++++++++++++++++++++++++

Ping for brilliance, diligence and hard work. Thanks for all you do.

[Wonder Warthog]

"So it wasn't a prescription for D - the 2x was over the counter?

Yes. NOW brand. But I was working with an MD and from blood tests during the initial "ramp up".

[goodnesswins]

Have you been re-tested yet? Doubt 2000iu will get you up much if you’ve been low .... (from the reading I’ve done.)

[Wilum]

Test is coming up. She initially put me on a substantially higher dose (50K?) for 2 weeks, then the 2k daily.