The experience of racial discrimination may be a key factor in explaining why African Americans have higher rates of obesity and suffer at higher rates from such diseases as diabetes and cardiovascular disorders, according to UCLA researchers.
Repeated responses to such discrimination — which include elevated blood pressure and heart rate — can cause enormous stress on a person's mental and physical health, according to research scheduled to be published in Volume 58 of the Annual Review of Psychology.
Race-based discrimination may help explain why African Americans, despite gains in civil rights and targeted health programs, continue to have the highest rates of diabetes, cardiovascular heart disease, hypertension and stroke as compared to all other racial or ethnic groups in the United States.
"This is not to say that every African American has poor health," said Vickie Mays, the report's lead author, a UCLA professor of psychology and health services and director of the Center for Research, Education, Training and Strategic Communication on Minority Health Disparities. "However, African Americans — as a group of people — have not been able to gain as much ground as other ethnic groups. That's when you need to worry and look at missing factors that can explain these health disparities."
When a person experiences discrimination, the body develops a cognitive response in which it recognizes the discrimination as something that is bad and should be defended against, Mays said. She said this response occurs for the most part even if the person merely perceives that discrimination is a possibility.
Starting with the brain's recognition of discrimination, the body sets into motion a series of physiological responses to protect itself from these stressful negative experiences, Mays said. These physiological responses include biochemical reactions, hyper-vigilance and elevated blood pressure and heart rate. With many African Americans, these responses may occur so frequently that they eventually result in the physiological system not working correctly.
According to Mays, the experience of race-based discrimination for some African Americans is akin to the response a person's body mounts when it experiences significant life-threatening danger, such as fear for a person's life or of a possible attack. She said that if the body mounts a response to protect itself against a "life-threatening" experience on a regular basis, after awhile it is strained and overworked. Many of the chemicals that come to its rescue can damage systems in the body that are associated with disease and obesity.
According to the report's authors, there has been much focus on the emotional impact of discrimination. But other critical factors — such as identifying how the brain recognizes and determines what racial discrimination is and how the body responds biochemically — may help researchers understand why African Americans are not benefiting from protections against negative health outcomes in the same manner as whites.
Health disparities in African Americans may even be passed down from one generation to the next. For example, even middle- and upper-class African American women are at a higher risk of delivering pre-term babies as compared to other ethnic minority and white women of the same social class.
"What may be occurring is that despite having a great education and prenatal care, your body may be programmed to deliver early because of the stresses experienced by your mother during her pregnancy," Mays said. Research suggests that African American women produce a hormone activated in response to stress that is often associated as a time-clock for birth.
"This results in the placenta separating itself a little bit early and, that may be one of the reasons for a preterm delivery," Mays said.
Another key factor is that African Americans faced with constant discrimination may experience high levels of stress that cause an "allostatic load." The term refers to the cumulative wear and tear of stress as the body responds to an overload of challenges and demands.
When the stress challenge to the cardiovascular system is prolonged and excessive to the point of allostasis, the immune system is suppressed, blood pressure increases and, over time, atherosclerosis can develop, resulting in coronary vascular disease.
