Childhood Experience, Genes Govern How Stress Affects Heart
People who live in poor households during childhood and carry a common variation in a gene are at greater risk of experiencing an increased heart rate and high blood pressure when under stress as adults, according to research from the Duke University Medical Center.
The genetic variant that the researchers examined is responsible for controlling levels of serotonin, which is a neurotransmitter that has multiple functions within the body, including regulation of emotions.
"This study is the first to look at how blood pressure reacts to stress among people with both low socioeconomic status and a common genetic make-up," said Redford Williams, M.D., lead study author and director of the Behavioral Medicine Research Center at Duke University Medical Center. "It shows how our genes can interact with our environment to influence susceptibility to disease."
Researchers conducted stress testing on 165 healthy volunteers, measuring their heart rate and blood pressure as they were asked to describe a stressful life event.
They found an association between study participants' father's education level, which was used to infer childhood socioeconomic status, and blood pressure. Study participants whose father had fewer years of formal education, correlating with a lower socioeconomic status, had a 25 percent higher blood pressure response to stress than those with a higher socioeconomic status, or a more educated father.
Childhood socioeconomic status also turned out to be a stronger predictor of how the heart responded to stress than one's current socioeconomic status as an adult.
Participants' genes were then analyzed and it was determined that people with one variant of the serotonin transporter gene had larger heart rate and blood pressure increases during the psychological stress test.
"We know that larger blood pressure responses to mental stress predict higher rates of cardiovascular disease later in life, so better understanding who is at risk is an area of priority for research," Williams said.
For example, the gene variation analyzed in this study has been found to be more common among the African American community, which may help explain higher rates of cardiovascular disease among this group of people.
The Duke team is conducting further research on the serotonin transporter gene to determine whether the effects of stress ultimately translate into increased rates of cardiovascular disease.
"This study suggests that people with a low socioeconomic status during childhood and a specific genetic make-up may benefit from behavioral interventions or medication," Williams said. "Beta-blockers, selective serotonin reuptake inhibitors and training in stress-coping skills are all potential options warranting further investigation," Williams said.