Racial Differences in Breast Cancer Rates may Relate to Age-Parity Differences

Researchers from Boston University have found that the higher breast cancer rate among young African American women compared to young Caucasian women may be explained by their differing patterns of childbearing.

In the US, in older age groups, breast cancer is more common among Caucasian women than black-African women. Black-African women generally have their children at a younger age and have more children. Pregnancy may transiently raise the risk for younger-age breast cancer.

The study involved 56,725 women over a 4-year follow-up wherein 349 women developed breast cancer. Among women younger than 45 years, having 4 or more births gave a 2.4-fold increased risk of breast cancer compared with priparity. Delaying the first pregnancy until at least 30 years of age was linked to a 2.5-fold increased risk of breast cancer compared with the first birth at younger than 20 years.

(Source: Journal of the National Cancer Institute 2003; 95: 478-483)