Researchers Spot Link Between Heart Disease, Income

By Ed Edelson
HealthDay Reporter
Tuesday, November 20, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

MONDAY, Nov. 19 (HealthDay News) -- A new study shows that lowered income actually has an inflammatory effect on the body, which may explain why people of lower socioeconomic status are at higher risk of heart disease, researchers report.

The link between higher levels of inflammatory molecules in the blood and lower income is weight gain, spurred by poor diet and lack of exercise, the study suggests.

"Lack of physical activity could be a factor, but it is less likely than diet," said study author Nalini Ranjit, an investigator at the University of Michigan School of Public Health.

The findings are published in the Nov. 20 issue of Circulation.

Ranjit and her colleagues studied data on more than 6,800 U.S. adults in the Multi-Ethnic Study of Atherosclerosis. With an average income of $51,000, 38 percent of the participants were white, 28 percent black, 22 percent Hispanic and 12 percent Chinese-American.

The researchers measured levels of two molecules found in the blood that are associated with inflammation -- interleukin-6 and C-reactive protein.

They found a direct relationship between levels of these inflammatory biomarkers and income.

Some people in the study made as much as $140,000 a year, Ranjit said, and people whose income was $41,300 below that figure had levels of IL-6 and CRP that climbed 6 percent to 9 percent higher compared to the top earners. The strongest association between income levels and inflammatory markers was seen among whites, she added.

Inflammation has long been linked to cardiovascular disease. It causes damage to blood vessels that can lead to blockage that results in heart attack, stroke or other cardiovascular problems.

While overweight was the singlemost important explanation for the link between lower socioeconomic status and a greater inflammatory burden, other factors did play a role, Ranjit said. "In an earlier paper, we showed that a general attitude of cynical distrust was associated with higher inflammatory molecule levels", she said. In addition, among blacks, smoking was associated with higher inflammatory molecule levels and lower levels of education, she added.