New Clues in a Breast Cancer Mystery

Few medical mysteries have been more vexing than the one facing residents of Marin County, California, where the breast cancer rate is among the highest in the country. Many residents suspect an environmental connection, though research thus far hasn’t confirmed such a link. Now there’s at least a clue. A recent study from the University of California, San Francisco fingers alcohol as a crucial factor. The study, cosponsored by members of Marin Breast Cancer Watch, looked at the lifestyle and medical history of 285 Marin County women with breast cancer and 286 women without the disease. By far, the most telling variable proved to be the women’s drinking habits. Women who had two alcoholic beverages a day were diagnosed with breast cancer at slightly more than twice the rate of women who drank less. Those who drank three or more a day faced nearly four times the risk. Not everyone thinks this solves the mystery, however. Even if the alcohol link is real, it doesn’t rule out the possible effect of chemical pollutants, which the study didn’t measure, says Jeanne Rizzo, executive director of the Breast Cancer Fund, a national advocacy group based in San Francisco. “Clearly, far more research is needed.”