THURSDAY, Jan. 23, 2020 (HealthDay News) -- The racism black Americans face may age them prematurely, a new study suggests.

This aging is occurring at the cellular level -- specifically, the shortening of telomeres, researchers say.

Telomeres are the repetitive sequences of DNA that sit at the tips of your chromosomes -- like the plastic caps at the ends of a shoelace -- and help keep the chromosomes from fraying.

Telomeres shorten with age -- and with stress. Shorter telomeres are linked to an increased risk of developing heart disease, stroke, diabetes and dementia.

"One of the factors that can lead to more rapid telomere shortening is high levels of stress," said researcher Dr. David Chae, an associate professor at Auburn University in Alabama.

"Racial discrimination is a particular type of stress experienced by African Americans that contributes to well-documented health disparities. We investigated one particular mechanism through which this occurs, namely, its impact on the telomere maintenance system," Chae said in a university news release.

For the study, the investigators collected data on nearly 400 black Americans who took part in the Coronary Artery Risk Development in Young Adults, Telomere Ancillary Study. Data were collected in 2000 when participants had an average age of 40, and the follow-up took place 10 years later. At both points, participants were asked about the discrimination they experienced in various situations.

"We found that greater accumulating experiences of racial discrimination during this midlife period was associated with a faster rate of telomere shortening," Chae said.

Racial discrimination was most commonly reported "on the street or in a public setting," "at work" and in "getting a job."

"Our results point to how racial discrimination, a particular type of social toxin that disproportionately impacts African Americans, becomes embedded at the cellular level," Chae explained. "Racism continues to be a pressing social and moral dilemma, as well as a public health issue."

While the study couldn't prove cause and effect, Chae noted that the findings pointed to the need for long-term research to study the biological consequences of racial discrimination and their implications for health.

The report was published online recently in the journal Health Psychology.

More information

For more on aging, visit the U.S. National Institute on Aging.