WASHINGTON, D.C., April 30 -- The more discrimination African-American women report, the more likely they are to have coronary artery calcification, a buildup of calcium in the vessels that is associated with atherosclerosis, according to a study presented at the American Heart Association's 45th Annual Conference on Cardiovascular Disease Epidemiology and Prevention.
These results indicate that chronic exposure to discrimination might increase the risk of cardiovascular disease in African-American women, the researchers reported.
"We know from other studies in this area that stressful life experiences can have an effect on cardiovascular outcomes," said Tené Lewis, Ph.D., a health psychologist in preventive medicine at Rush University Medical Center, Chicago. "Discrimination appears to be a stressor that has particular relevance for the health of African-American women."
Previous research has suggested that social status stressors in the form of discrimination and unfair treatment may have a negative impact on a variety of risk factors for heart disease, she said. "Most of these studies have focused on clinically manifest disease, which may actually underestimate the impact of discrimination on cardiovascular outcomes."
This research, which used a subset of the Study of Women's Health Across the Nation (SWAN) Heart study, examined the relationship between chronic exposure to discrimination and subclinical outcomes such as coronary artery calcification. Such calcification is believed to be a measure of overall atherosclerotic plaque burden, with some studies finding that arterial calcification is predictive of clinical events such as heart attack.
The study included 181 African-American women, ages 45 to 58, from the Chicago, and Pittsburgh, Pa., areas. The women answered a nine-item Everyday Discrimination Questionnaire regarding their experience of discrimination and the results were averaged over a four-year period. Coronary artery calcification was measured on the fourth year through electron beam computed tomography.
The questionnaire measured subtle rather than overt discrimination on a scale of one to four, with four points being the highest.
Discrimination was measured by things such as feeling ignored or treated with a lack of courtesy or respect, she said. "The women reported discrimination in the form of having poorer service in stores or restaurants, being treated as if they were less smart or being treated as if they were dishonest."
The discrimination that people face today is more subtle, Lewis said. "It's rare that someone would use blatantly racist language in public, but that doesn't mean that discrimination is no longer a problem."
Coronary artery calcification was present in 59.6 percent of the women. The more discrimination they reported, the more likely they were to have any calcification, she said.
Discrimination scores ranged from 1 to 3.2 for individual women, with an average score of 1.86 on the four-point scale. "Some reported low amounts of discrimination, others reported high, but the bulk of women were in the middle," she said.
After adjustments for age, study site and education, for every one unit increase in perceived discrimination on the four-point scale the odds of having any coronary calcification increased 2.8 fold. "There is a dose-response relationship," said Lewis. "The more discrimination African-American women experience, the more calcium buildup they have."
The odds of having any coronary calcification remained at 2.6-fold after researchers adjusted for Framingham risk scores based on high blood pressure, high cholesterol, smoking and age. After further adjustment for body mass index (BMI) there still was a nearly 2.5 times higher risk for each unit increase up the four-point scale.
"These findings suggest that chronic exposure to discrimination may be an important risk factor for cardiovascular disease in African-American women," Lewis said. It is important to identify coping strategies that might reduce the negative effects of discrimination on health outcomes for African-American women, she said.
"This is an unavoidable stressor for African-American women," she said. "Because we can't change society, we need to focus on helping African-American women cope more effectively with these encounters. We really need to come up with some specific strategies in dealing with discrimination."
Further studies are needed to find out if other minority women experience discrimination and health outcomes in the same way, and whether the stress of discrimination might spark inflammation that could contribute to the onset of atherosclerosis. "Other studies have found that inflammatory markers might be prevalent in people who feel socially rejected," she said.
Co-authors are Susan Everson-Rose, Ph.D.; Lynda H. Powell, Ph.D.; Karen Matthews, Ph.D.; Kelly Karavolos, M.A.; Charlotte Brown, Ph.D.; Kim Sutton-Tyrell, Ph.D.; and Elizabeth Jacobs, M.D.
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