The unpleasant results of study were recently published in the Journal of the National Cancer Institute. Analysis of data on more 91,000 women with no history of cancer collected during the famous Nurses’ Health Study II showed that consuming about 10 grams of alcohol between menarche and the first pregnancy six times a week was associated with an 11% increase in chance to get breast cancer. Such consumption is equivalent a drink six times a week, where one drink was defined as one bottle/can of beer, a 4-ounce glass of wine, or a shot of liquor. The more alcohol was consumed on a daily basis the more risks of developing breast cancer later in life had the woman.
Another factor was the time between the woman’s fist menstruation and her first pregnancy. Compared with nondrinkers with a shorter duration, nondrinkers with duration of 10 or more years between menarche and first pregnancy had 26% increased risk of breast cancer. Pregnancy makes breast tissue less susceptible to carcinogens. Additionally, first pregnancy induces long-term hormonal changes, which provide further protection against breast cancer. Importantly, the researchers found that alcohol drinking between menarche and first pregnancy conferred excess risk of breast cancer among women who had first pregnancy 10 or more years after menarche.
Worldwide, breast cancer is the most common invasive cancer in women. Researchers estimate that 1 in 8 women will be diagnosed with breast cancer at some time in their lives, and the chance that breast cancer will be responsible for a woman’s death is about 1 in 36.
Contrary to popular belief fueled by the recent surgery of Angelina Jolie, most breast cancers are not inherited. Poor heredity is responsible for only 5% to 10% of breast cancers overall.
It makes sense to try to minimize other 90% – 95%.