Women who consume as few as three to six glasses of alcohol per week may modestly up their risk for breast cancer, a new study suggests.
The research, published in the Journal of the American Medical Association, may make some women pause as they reach for the wine glass -- and given that several recent studies have linked moderate alcohol use with various health benefits, it could confuse other casual drinkers as well.
Researchers studied 105,986 women through the famous Nurses' Health Study and collected data on their alcohol consumption from 1980 to 2008. They found that women who consumed three to six drinks of alcohol per week had a 15 percent increased risk of breast cancer, while women who consumed two drinks per day had a more than 50 percent greater risk than women who did not drink. There was no difference among women who drank wine, beer or liquor.
"There aren't many modifiable risk factors for breast cancer, so it's important to think about this," study author Dr. Wendy Chen said. "We looked at breast cancer exposure risk with cumulative exposure to alcohol and didn't just focus on what someone was doing for one or two months. That's the most important message."
Previous studies have found an increased risk of breast cancer associated with alcohol intake. But Dr. Mary Beth Terry, an epidemiologist at Columbia University in New York, said, "The size of the study also meant that patterns of use could be investigated with greater precision than many studies, and overall, the study supports [the idea that] cumulative intake is important. As alcohol intake may likely be underreported generally, this means that the association with breast cancer is likely larger."
But what about previous research that has found that moderate alcohol intake can benefit heart health? Dr. Chip Lavie, at the John Ochsner Heart and Vascular Institute in New Orleans, hesitated to tell women to abstain from alcohol.
"[Even] small amounts of alcohol have larger protective effects against heart attack and stroke," Lavie said. "Since only one in 25 women die of breast cancer, and nearly one in two or at least one in three die of cardiovascular disease, such as heart attack and stroke, the net benefits of small alcohol intake likely well outweigh the risks for most women."
Nevertheless, Dr. Robert Bonow, a cardiologist at Northwestern University in Chicago, said in an email that he believed there was "strong evidence for less-hazardous approaches to [cardiovascular] risk reduction -- weight control, diet, exercise, not smoking and controlling cholesterol and blood pressure," and that no amount of alcohol would compensate for an unhealthy lifestyle.
So what should women do? Both Chen and other experts agree that all women should be educated about the risks and benefits of alcohol use, and consider their individual risk factors for breast cancer and heart disease before going for those drinks.
"We're not telling women not to drink at all," said Chen. "This is just an average, and lifetime consumption and other factors will need to be accounted for."
Current American Heart Association Guidelines recommend that women have no more than one drink per day. Most experts echo the sentiments of what Dr. Deborah Axelrod, breast cancer surgeon at New York University, tells all of her patients, "If you don't drink, then don't start."