African-American women who give birth to four or more children appear to be at an increased risk of breast cancer before the age of 45, according to a new study published in the Journal of the National Cancer Institute.

However, the same study found that African-American women who give birth to four or more children have a decreased risk of developing breast cancer at age 45 or older.

"These results may shed light on the puzzling differences in breast cancer incidence rates for African-American and white U.S. women," notes lead author Julie R. Palmer, Sc.D., of Boston University, and her colleagues. They point out that, in the United States, breast cancer incidence is higher among African-American women than among white women before age 45 but lower at older ages.

The study involved 56,725 women who were participating in the Black Women's Health Study.

SOURCE:
Journal of the National Cancer Institute, March 19, 2003