Researchers at Washington University in St. Louis have published findings that indicate women who drink alcohol regularly while young may increase their lifetime risk for breast cancer. The authors argue that young women should drink less than a glass a day, but also say they have not studied wine specifically.
Several past scientific studies have addressed the relationship between alcohol consumption and cancer, but this work focused on the effect of the timing of alcohol exposure. Published in the Journal of the National Cancer Institute, the study considered 91,005 mothers who participated in the Nurses’ Health Study II from 1989 through 2009. None had a history of breast cancer at the outset, and all were polled on their alcohol consumption in early life. The 20-year investigation tracked subjects’ alcohol consumption and followed the development of breast cancer and proliferative benign breast disease (BBD), a known predictor of breast cancer.
According to Ying Liu, instructor at Washington University School of Medicine and lead author, her team found that a woman’s drinking habits between menarche (the time of her first menstrual period) and her first full-term pregnancy have a linear relationship to her breast cancer risk. For every 10 grams per day of alcohol consumed on average during this time period, a woman’s likelihood of developing breast cancer increases by 11 percent, and her likelihood of developing BBD increases by 16 percent. (A typical 5-ounce glass of wine contains about 14 grams of alcohol.)
Put simply, Liu told Wine Spectator, “The more you drink before [your] first pregnancy, the higher the risk of breast cancer.”
Why does the time period between menarche and the first pregnancy matter so much? “Breast tissue undergoes rapid cellular proliferation during this time,” said Liu, making the body more susceptible to carcinogens. Pregnancy “induces the full differentiation of the breast tissue,” which lessens the impact of carcinogenic exposure. Subsequent pregnancies strengthen this effect. Irrespective of alcohol consumption, there is considerable evidence that a woman increases her breast cancer risk when the interval between menarche and first pregnancy is longer.
Thus Liu was not surprised that alcohol, which previous studies have pegged as a carcinogen, should affect breast cancer risk when consumed regularly during this critical period in a woman’s life. “I think young women should consider [reducing] their alcohol intake to less than one drink a day, based on our study,” Liu said.
The Washington University study did not consider whether various types of alcohol could have different effects. Liu noted that future research would do well to distinguish wine, beer and liquor consumption when polling its subjects. It’s possible that red wine may affect cancer development differently from other types of alcohol because of the presence of antioxidants, whose ability to fight cancer has been a subject of debate in recent years. And those worried about cancer must weigh the potential cost of not drinking against the proven benefits of red wine in fighting heart disease.
Liu and her team will next focus on potentially protective agents that could counter the adverse effects they have found in alcohol. She hypothesizes that exercise and a high-fiber diet during the window between menarche and first pregnancy could protect women from lifetime breast cancer risk.