Featured Research

from universities, journals, and other organizations

Heredity Plays Big Role In Heart Disease Risk Factors

October 20, 2005
Medical College of Georgia
Heredity plays a major role in determining the blood lipid profile and heart rate variability of blacks and whites, two major risk factors for coronary artery disease, researchers say.

Dr. Xiaoling Wang (foreground),postdoctoral fellow; Dr. Catherine L. Davis, clinical health psychologist; and Dr. Harold Snieder, genetic epidemiologist are exploring the role of genetics in risk factors for heart disease.
Credit: Photo by Phil Jones

Related Articles

“There aresome interesting ethnic differences in cardiovascular risk factors,including the fact that blacks tend to have higher HDL (high-densitylipoprotein) and lower triglycerides, which is an advantage, and wesuspect it is due to genetic influences,” says Dr. Catherine L. Davis,clinical health psychologist at the Medical College of Georgia.

Coronary artery disease rates in the United States are similar or lower in blacks yet blacks have higher mortality rates.

Dr.Davis and her colleagues at MCG’s Georgia Prevention Institute examinedheritability – the percentage of a variable attributable to genes – tobetter understand the influence of genetics and environment on hearthealth.

Heritability studies were enabled by data MCG iscollecting on 500 pairs of twins – blacks and whites, identical andfraternal – to determine whether environmental stress is a risk factorfor cardiovascular disease. Identical twins have identical genes andfraternal twins share about 50 percent of their genes, much like normalsiblings.

“Any differences between identical twins must be due tothe environment,” says Dr. Harold Snieder, genetic epidemiologist. “Soyou can quantify the part that is due to genetics,” he says, notingthat heritability provides an aggregate look at the effect of genes,many of which may still be unknown.

Across both races they foundthat lipid levels, which include so-called good cholesterol, HDL, andbad cholesterol, LDL, as well as triglycerides, are 60 percent to 80percent determined by genetics.

A separate study found heart ratevariability – the heart’s ability to respond to changing demands – washeritable and equally so, about 70 percent, among young blacks andwhites, Dr. Snieder says.

“We also were able to confirm thatblacks indeed showed a more favorable pattern of heart ratevariability,” he says. “If you have a lot of variability, it means yourheart is able to cope well with changing demands. The heart needs toadapt all the time in real life,” says Dr. Snieder.

“It’s a paradox,” Dr. Davis says. “It’s the opposite direction you would expect given the disparities in health outcomes.”

“We would have expected environmental influences to be more important in blacks,” adds Dr. Snieder. “We did not find that.”

Whatthey did find they hope will provide new insight and possibly new, moretargeted treatment strategies for a cross section of people with heartdisease.

“What we are very interested in is how these riskfactors for cardiovascular disease develop over time and to what extentthe development is influenced by genes and environment,” says Dr.Snieder, who plans on gathering longitudinal data on an even largerpercentage of the twins he’s following.

“Even having these genesdoesn’t make blacks into long-lived healthy people necessarily,” saysDr. Davis. “But maybe that link could help scientists develop medicinesthat target the protein that gene encodes, to help people who have hightriglycerides try to correct them or try to help them raise their HDL.”

Thelipid study, published in the October issue of Twin Research and HumanGenetics, included 106 black twins and 106 white twins. The heart ratevariability study, published in the October issue of the AmericanJournal of Cardiology, looked at 166 adolescents, 104 pairs of twinsand 11 individual twins.

A related candidate gene study,published in the October issue of Ethnicity and Disease, looked at ahandful of genes linked to obesity and implicated in lipid metabolismin mostly unrelated individuals: 413 health adolescents and youngadults who were 44 percent black and 53 percent male. Researcherswanted to explore the relationship between these genes and lipid levels– in general, lipid levels worsen when weight increases – as well asany racial differences, Dr. Davis says.

They found whites weremuch more likely to have a variation of the LDL receptor gene thatraises triglycerides. A mutation in a second candidate gene, ApoB,seemed to predict total cholesterol but the total varied with body massindex: heavier people were more affected by the gene. Those under age18 with the same ApoB variant had a higher total cholesterol. Theeffect of that variant wasn’t seen in adults, making researcherssuspect its activity might be tied to puberty. Also, a variant of TNFagene was linked to a lower HDL in men. “Women are known to have higherHDL levels than men,” Dr. Davis says. “This gene might be interactingwith sex hormones to influence men’s HDL levels and make them a bitlower.”

Co-authors on the studies include Dr. Xiaoling Wang, Dr.Snieder’s postdoctoral fellow; Dr. Frank A. Treiber, MCG vice presidentfor research and vice chair of basic research for the Department ofPediatrics; Dr. Julian F. Thayer, Emotions and QuantitativePsychophysiology Section, National Institute on Aging, GerontologyResearch Center, Baltimore; and Dr. Anastasia Illiadou, ClinicalEpidemiology Unit, Department of Medicine, Karolinska Institute,Karolinska University Hospital, Stockholm.

Story Source:

The above story is based on materials provided by Medical College of Georgia. Note: Materials may be edited for content and length.

Cite This Page:

Medical College of Georgia. "Heredity Plays Big Role In Heart Disease Risk Factors." ScienceDaily. ScienceDaily, 20 October 2005. <www.sciencedaily.com/releases/2005/10/051015092407.htm>.
Medical College of Georgia. (2005, October 20). Heredity Plays Big Role In Heart Disease Risk Factors. ScienceDaily. Retrieved March 27, 2015 from www.sciencedaily.com/releases/2005/10/051015092407.htm
Medical College of Georgia. "Heredity Plays Big Role In Heart Disease Risk Factors." ScienceDaily. www.sciencedaily.com/releases/2005/10/051015092407.htm (accessed March 27, 2015).

Share This

More From ScienceDaily

More Health & Medicine News

Friday, March 27, 2015

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

These Popular Antibiotics Can Cause Permanent Nerve Damage

These Popular Antibiotics Can Cause Permanent Nerve Damage

Newsy (Mar. 27, 2015) — A popular class of antibiotic can leave patients in severe pain and even result in permanent nerve damage. Video provided by Newsy
Powered by NewsLook.com
House Ready to Pass Medicare Doc Bill

House Ready to Pass Medicare Doc Bill

AP (Mar. 26, 2015) — In rare bipartisan harmony, congressional leaders pushed a $214 billion bill permanently blocking physician Medicare cuts toward House passage Thursday, moving lawmakers closer to resolving a problem that has plagued them for years. (March 26) Video provided by AP
Powered by NewsLook.com
What's Different About This Latest Ebola Vaccine

What's Different About This Latest Ebola Vaccine

Newsy (Mar. 26, 2015) — A whole virus Ebola vaccine has been shown to protect monkeys exposed to the virus. Here&apos;s what&apos;s different about this vaccine. Video provided by Newsy
Powered by NewsLook.com
HIV Outbreak Prompts Public Health Emergency In Indiana

HIV Outbreak Prompts Public Health Emergency In Indiana

Newsy (Mar. 26, 2015) — Indiana Gov. Mike Pence says he will bring additional state resources to help stop the epidemic. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins