A doctor examines a breast x-ray in an undated photo. Tools used to predict whether a woman's breast cancer is inherited do not account for smaller families and may leave some women in the dark about their risk for future cancers, U.S. researchers said on Tuesday. [Reuters]

The study, which followed 59,000 African-American women for six years, found that those who reported more incidents of racial discrimination had a higher risk of breast cancer.

The relationship was stronger among women younger than 50, researchers found. This finding is particularly interesting, they note, in light of the fact that, unlike the case with older women, breast cancer is more common among young black women than young white women.

It's possible that racial discrimination plays some role, according to the researchers, led by Dr. Teletia R. Taylor of Howard University in Washington, D.C.

They report their findings in the American Journal of Epidemiology.

Past studies have suggested that over time, perceived racial discrimination can take a toll on a person's health. A possible explanation is that unjust treatment serves as a source of chronic stress, which itself has been linked to poorer physical health.

In the current study, women were asked how often they faced "everyday" discrimination, like receiving poorer service than other people at stores, or feeling that people are "afraid" of them or act superior to them.

They were also asked whether they'd ever been treated unjustly on the job, in trying to get housing, or by the police -- all considered examples of "major" discrimination.

Overall, Taylor's team found, women who said they frequently ran up against everyday types of discrimination had a higher risk of developing breast cancer. The same pattern was seen with major discrimination; women who reported on-the-job discrimination, for example, had a 32 percent higher risk of breast cancer than women who reported no such prejudice.

Women who said they'd faced discrimination on the job, in housing and from the police were 48 percent more likely to develop the disease than those who reported no incidents of major discrimination.

More studies, according to Taylor's team, are needed to confirm these findings, and to uncover the reasons for the connection between racism and breast cancer.