Narrator: This is Science Today. In studying breast cancer rates, epidemiologists discovered women living in urban areas have the highest rate of breast cancer. But Virginia Ernster, a professor of epidemiology at the University of California, San Francisco says geography is not solely to blame for the high rates of breast cancer.
Ernster: The reason we see the high rates in those areas is because of the kind of women who live in say, San Francisco. We tend to be, compared to the rest of the U.S. population, more well educated, to have the kinds of careers that mean that we're postponing child bearing or choosing not to have children. And those are two of the risk factors for breast cancer.
Narrator: Ernster says breast cancer is one of the few diseases that is positively associated with higher socioeconomic status.
Ernster: So unfortunately it's women who are of higher education, who have more childbearing choice and longer life expectancy that are at higher risk to breast cancer.
Narrator: For Science Today, I'm Larissa Branin.