Many epidemiological studies have indicated a positive relation between alcohol consumption and incidence of breast cancer [68;70-72]. The risk exists even at a moderate level of alcohol drinking [73] and increases monotonically with the level of alcohol consumption [68;71]. Based on several epidemiological studies, each additional 10g (less than one standard drink in most countries) of alcohol per day is associated with an increase of 7% in the RR of breast cancer [71] or higher (an increase of 10% was estimated [72]). Hamajima and colleagues [71] estimated that about 4% of the female breast cancer cases in developed countries may be attributable to alcohol drinking.
