Lifestyle May Counter Genetic Influence on Blood Pressure
< Jun. 17, 2009 > -- Having a genetic makeup that can promote the development of high blood pressure does not necessarily mean that a person will acquire the condition.
"It's been known for many years that blood pressure is affected by genes," says 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."
The study, reported online this week in Circulation: Cardiovascular Genetics, "reinforces the message that lifestyle changes can alter the effect of genetics," Dr. Franceschini says.
It is an important finding because high blood pressure is a major risk factor for heart attack, stroke, and other cardiovascular diseases.
Dr. Franceschini's team looked at data from the Strong Heart Family Study, which is a study of diabetes and high blood pressure among American Indians in Arizona, North and South Dakota, and Oklahoma. The incidence of both conditions is high in this group. 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, says Dr. Franceschini.
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, according to Dr. Franceschini. 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 says.
The findings help answer whether genes alone determine high blood pressure, says 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," Dr. Stein says. "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, Dr. Franceschini says. Analysis of the entire genome "may allow us to identify the particular genes that account for the interaction," she adds.
Always consult your physician for more information.
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Blood pressure, measured with a blood pressure cuff and stethoscope by a healthcare provider, is the force of the blood pushing against the artery walls. Each time the heart beats, it pumps blood into the arteries, resulting in the highest blood pressure as the heart contracts.
One cannot take his or her own blood pressure unless an electronic blood pressure monitoring device is used. Electronic blood pressure monitors may also measure the heart rate, or pulse.
Two numbers are recorded when measuring blood pressure. The top number, or systolic pressure, refers to the pressure inside the artery when the heart contracts and pumps blood through the body. The bottom number, or diastolic pressure, refers to the pressure inside the artery when the heart is at rest and is filling with blood.
Both the systolic and diastolic pressures are recorded as "mm Hg" (millimeters of mercury). This recording represents how high the mercury column is raised by the pressure of the blood.
High blood pressure, or hypertension, directly increases the risk of coronary heart disease (heart attack) and stroke (brain attack). With high blood pressure, the arteries may have an increased resistance against the flow of blood, causing the heart to pump harder to circulate the blood.
Nearly one-third of all Americans have high blood pressure, but it is particularly prevalent in:
- people in their early to middle adult years; men in this age group have higher blood pressure more often than women in this age group
- people in their middle to later adult years; women in this age group have higher blood pressure more often than men in this age group (more women have high blood pressure after menopause than men of the same age)
- middle-aged and elderly people - more than half of all Americans age 60 and older have high blood pressure
- people whose parents or grandparents have/had high blood pressure
- obese people
- heavy drinkers of alcohol
- women who are taking oral contraceptives
Always consult your physician for more information.
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