TUESDAY, June 16, 2009 (HealthDay News) --Being born with genes that predispose you to high blood pressure doesn't mean you're doomed to have it, a long-term study shows.
"It's been known for many years that blood pressure is affected by genes," said Dr. Nora Franceschini, an assistant professor of epidemiology at the University of North Carolina and lead author of a report on the study. "It's also known that lifestyle affects blood pressure. Now we are showing that they interact, and that the effect of those genes varies among individuals who have different behaviors."
It's an important finding because high blood pressure is a major risk factor for heart attack, stroke and other cardiovascular diseases. The study, reported online Tuesday in Circulation: Cardiovascular Genetics, "reinforces the message that lifestyle changes can alter the effect of genetics," Franceschini said.
That message comes from the Strong Heart Family Study, which has been looking at diabetes and high blood pressure among American Indians in Arizona, North and South Dakota and Oklahoma, an ethnic group in which the incidence of both is high. The study now includes more than 3,600 people aged 14 to 93.
The new report shows that different lifestyles and socioeconomic status influence the effect of inherited genetic patterns.
About 15 percent of the variation in diastolic blood pressure, the lower of the two numbers in a blood pressure reading, is because of genes, Franceschini said. The study linked the effects of three behavioral traits -- drinking, smoking and exercise -- with that of the genes. It also looked at education level, a socioeconomic factor.
The study found that genes for high blood pressure have a greater effect in smokers than nonsmokers, Franceschini said. It also found a similar effect for physical exercise. And it found that blood pressure among drinkers is affected by different genes than in people who quit drinking or never drank.
"Our study shows a comprehensive effect across multiple behaviors," she said.
The findings help answer whether genes alone determine high blood pressure, said Dr. Richard A. Stein, a professor of medicine and director of the urban community cardiology program at New York University and a spokesman for the American Heart Association.
"The answer is, not by a long shot," Stein said. "The actual effect is explained only by adding behavioral and socioeconomic factors into the equation. It is actually more how you live than what you are born with."
The next step in the study is an effort to identify the specific genes that interact with each of the behavioral traits to increase blood pressure, Franceschini said. Analysis of the entire genome "may allow us to identify the particular genes that account for the interaction," she said.
Another study reported in the same issue of the journal showed that small changes in measures aimed at controlling high blood pressure can produce significant results.
One such measure was distribution of wallet cards to track clinic visits, document blood pressure, update drug data and provide contact information, according to a report from the VA-Tennessee Valley Healthcare System.
More than 30,000 such cards were given to veterans in the system, and the result was a 4.2 percent improvement in blood pressure control, which translates into a significant reduction of cardiovascular risk, the report said.
The U.S. National Heart, Lung and Blood Institute has more on high blood pressure.