You want to know it exactly? Every additional drink (ten grams of alcohol) a day makes the breast cancer risk of a woman rise by three percent. This figure has been calculated in a European study, based upon a huge database from more than a quarter million of women.
The bigger the number, the more precise statistics, they say. But for a single woman, even a most precise statistic has not much to tell. In general, the risk of breast cancer is low, and three percent of a low level is very, very little. But projected up to all European women, we speak of 129 additional women with breast cancer if they all would consume one more drink daily.
However, most interestingly, this effect does not last. If lifetime alcohol intake is considered, there is no link to breast cancer at all. Therefore, alcohol increases breast cancer risk only if a woman begins to drink more than she did before. The reason could be that she has a problem, and this problem may help to promote cancer. - (Picture by johnnyalive @ Flickr)