Women who drink 30 grams of alcohol or more daily have a 43-percent greater risk of developing breast cancer than nondrinkers, according to researchers affiliated with the Women's Health Study.

Harvard researcher Shumin Zhang and colleagues studied data on about 39,000 women and also concluded that breast-cancer risk rises 11 percent for every 10-gram increase in daily alcohol consumption. The increased risk applied to estrogen- and progesterone-positive breast cancers.

The research was published in the March 15, 2007 issue of the American Journal of Epidemiology.