Are you stressed? Results of a new meta-analysis of six studies involving nearly 120,000 people indicate that the answer to that question may help predict one's risk of incident coronary heart disease (CHD) or death from CHD. The study, led by Columbia University Medical Center researchers, was published in a recent issue of the American Journal of Cardiology.
The six studies included in the analysis were large prospective observational cohort studies in which participants were asked about their perceived stress (e.g., "How stressed do you feel?" or "How often are you stressed?"). Respondents scored either high or low; researchers then followed them for an average of 14 years to compare the number of heart attacks and CHD deaths between the two groups. Results demonstrate that high perceived stress is associated with a 27% increased risk for incident CHD (defined as a new diagnosis or hospitalization) or CHD mortality.
"While it is generally accepted that stress is related to heart disease, this is the first meta-analytic review of the association of perceived stress and incident CHD," said senior author Donald Edmondson, PhD, assistant professor of behavioral medicine at CUMC. "This is the most precise estimate of that relationship, and it gives credence to the widely held belief that general stress is related to heart health. In comparison with traditional cardiovascular risk factors, high stress provides a moderate increase in the risk of CHD - e.g., the equivalent of a 50 mg/dL increase in LDL cholesterol, a 2.7/1.4 mmHg increase in blood pressure or smoking five more cigarettes per day."
"These findings are significant because they are applicable to nearly everyone," said first author Safiya Richardson, MD, who collaborated with Dr. Edmondson on the paper while attending the Columbia University College of Physicians and Surgeons (she graduated in 2012 and is currently a resident at North Shore Long Island Jewish Health System in Manhasset, New York). "The key takeaway is that how people feel is important for their heart health, so anything they can do to reduce stress may improve their heart health in the future."
Coronary heart disease (CHD), also called coronary artery disease, is a narrowing of the small blood vessels that supply blood and oxygen to the heart. It is caused by a buildup of plaque in the arteries, which can lead to hardening of the arteries, or atherosclerosis. CHD is the leading cause of death in the United States for men and women; more than 385,000 people die each year from CHD.
The researchers did further analysis to try to learn what might underlie the association between stress and CHD. They found that while gender was not a significant factor, age was. The people in the studies were between the ages of 43-74; among older people, the relationship between stress and CHD was stronger.
"While we do not know for certain why there appears to be an association between age and the effect of perceived stress on CHD, we think that stress may be compounding over time. For example, someone who reports high perceived stress at age 60 may also have felt high stress at ages 40 and 50, as well." Dr. Edmondson also noted that older individuals tend to have worse CHD risk factors such as hypertension to begin with, and that stress may interact with those risk factors to produce CHD events.
"The next step is to conduct randomized trials to assess whether broad population-based measures to decrease stress are cost-effective. Further research should look at whether the stress that people report is about actual life circumstances (e.g., moving or caregiving), or about stable personality characteristics (e.g., type A vs. B), said Dr. Edmondson.
"We also need to ask why we found this association between stress and CHD, e.g., what biological components or mechanisms are involved, and what is the role of environment or lifestyle (e.g., diet, alcohol and drug use, exercise), and how best to moderate these factors to lower the risk of CHD," said Dr. Richardson.
American Journal of Cardiology