More and more evidence is mounting that links depression and other psychological disorders to cardiovascular events. Now researchers have found that psychological distress also is associated with an increased risk of death due to stroke. The results were published online June 18 in the Canadian Medical Association Journal.
In recent years, research has shown that depression is a risk factor for coronary artery disease, while a study published this month found that post-traumatic stress disorder was relatively common in patients with acute coronary syndrome and doubled their risk of death and recurrent cardiac events. But there has been little research focusing on cerebrovascular disease and psychological distress, and the few completed studies were hampered by small sample sizes, wrote Mark Hamer, PhD, of the epidemiology and public health department at University College London, and colleagues.
The researchers devised their study to overcome those limitations by tapping into the annual Heart Survey of England, a representative, general population-based sampling of people living in the U.K. The survey is based on visits to households where interviewers collect data using a 12-item version of the General Health Questionnaire (GHQ-12). The items address issues such as depression, anxiety, social dysfunction and loss of confidence that can be used to measure psychological distress.
The primary outcome was death due to cerebrovascular disease, which was determined through death certificates and information from certifying physicians.
After excluding people who declined to give consent and those who had clinician-diagnosed cardiovascular disease at baseline, they had a sampling stratified by geography of 68,652 adults from the 1994 through 2004 surveys. The mean age was 54.9 years and 45 percent were men and 96.1 percent were white. They recorded 2,367 deaths due to cardiovascular disease; 562 deaths due to cerebrovascular disease and 795 other cardiovascular-related deaths at an average of 8.1 years of follow-up.
They calculated that 14.7 percent of participants reported psychological distress. Younger age, being female, lower and working class status, smoking and using hypertensive medications was associated with distress. Participants with symptoms of distress had an increased risk of death from cerebrovascular disease and an increased risk of death from ischemic heart disease compared with participants with no symptoms of distress.
“Previous studies have been limited by the rarity of cerebrovascular events, limited range of covariables, the unknown influence of existing comorbidity on psychological distress (reverse causality) and few data from women,” Hamer and colleagues wrote. “Our study adds substantially to the extant literature, because it overcomes some of these weaknesses by employing a large, well-characterized cohort with a sufficient number of cardiovascular disease events.”
Nonetheless, they wrote that many of the patients excluded from their sample were older, which could bias the results, and they could not discount the possibility of reverse causation.
They noted that the effect estimates of psychological distress were similar for cerebrovascular and ischemic heart disease, but suggested the mechanisms may be different due to differences in pathogenesis of atherosclerotic lesions in coronary and cerebral arteries. Blood pressure, they wrote, may be a plausible mechanism for the link between psychological distress and stroke.
“Our data suggest that questionnaires such as the GHQ-12 could be of value in systematic screening aimed at improving the recognition of common mental disorders for reducing the risk of cardiovascular disease,” Hamer and colleagues concluded, recommending a controlled clinical trial be conducted to study the effects of reducing distress on outcomes.