People from the lowest rungs of the socioeconomic strata are the most vulnerable to have heart diseases, says a new study conducted by researchers in the United States.

Researchers at David Geffen School of Medicine, University of California, Los Angeles, analyzed data from 12,154 participants in the National Health and Nutrition Examination Survey (2001-2006) and found that the poorest people had the highest risk of cardiovascular disease.

Even though the poorest has the highest risk, the incidence rates varied between racial and ethnic groups, found the new study which involved whites, blacks, U.S.-born Mexican Americans and foreign-born Mexican Americans.

But the common denominator was their lower socioeconomic status. The lower the person's socioeconomic status, the greater was her risk of cardiovascular disease, regardless of all racial and ethnic groups.

"Most ethnic differences in cardiovascular risk are really due to socioeconomic differences between the races in the U.S. – barring one outstanding exception. Foreign-born Mexican Americans, as opposed to Mexican Americans born here, are healthier than everyone else, and this may have less to do with ethnicity or genes than with migration patterns," lead researcher Dr. Arun Karlamangla, an associate professor of medicine in the division of geriatrics at David Geffen School of Medicine, University of California, Los Angeles, says.

"Only the healthy are able to migrate here, and the unhealthy go back for their care," he suggests in the study is published in the August issue of the journal Annals of Epidemiology.

The authors noted that lifestyle differences contributed much to the increased risk of heart diseases. Poor people, for example, tend to exercise less and are more likely to be obese and to smoke.

Socioeconomically disadvantaged individuals need to be specifically targeted for early risk detection and management, and health behaviour counselling if we are to improve the cardiovascular health of the nation, the researchers said.