SAN FRANCISCO — Heavy drinking significantly increases the risk of developing breast cancer, and even moderate drinking — just a glass or two of wine with dinner every night — can make women more vulnerable to the disease, according to research by Kaiser Permanente doctors.
The study of more than 70,000 Kaiser patients, results of which were presented Wednesday at the European Cancer Conference in Spain, showed that women who drank three or more alcoholic beverages a day increased their risk of breast cancer by 30 percent. Women who drank one or two a day increased their risk by 10 percent.
Notably, it didn’t matter what kind of alcohol the women drank, researchers said. That’s an important distinction for wine drinkers, as research has shown that red wine might have some benefits, especially for cardiovascular health.
But moderate drinkers shouldn’t necessarily stop having their daily glass of wine, the study’s authors said. The risk of breast cancer is low enough that they’ll want to take into consideration potential health benefits of drinking small amounts of alcohol.
Women who are heavy drinkers, however, or those who are already at high risk of developing breast cancer because of genetic factors, might want to reconsider their drinking habits, said Dr. Yan Li, co-author of the Kaiser study.
“Women should avoid heavy drinking, but in terms of light drinking, that depends on the patient’s circumstances,” Li said.
“A woman who drinks one glass of wine every night, whether she should keep doing that should depend on her own health, her family history,” she said. “If a woman is relatively young and has a strong history of breast cancer or carries the gene for breast cancer, perhaps she should do everything she can in life to avoid factors that increase her risk.”
“This study really conclusively and convincingly tells us that the source of the alcohol does not appear to make a difference,” said Dr. Robert Carlson, an oncologist with the Stanford Cancer Center. “There has been some belief previously that red wine might not confer the same risk, and this shows that it does.
“The important thing is that most risk factors for breast cancer are not modifiable, and alcohol consumption is,” he said.