Alcohol drinking is also strongly associated with the risk of primary liver cancer; the mechanism, however, might be mainly or solely via the development of liver cirrhosis, implying that light or moderate drinking may have limited influence on liver cancer risk. An increased risk of colorectal cancer has been observed in many cohort and case-control studies, which seems to be linearly correlated with the amount of alcohol consumed and to be independent of the type of beverage.Evidence regarding an associated between alcohol consumption and breast cancer risk has come to the fore during the past 20 years. It therefore seems appropriate to look at some of the key studies and to monitor the evolution of the accumulation of the evidence for association and the public health responses.Throughout the following text, one drink - whether a glass of beer, a standard glass of wine, or a measure of spirits - will be considered to contain 10 g ethanol.The Nurses' Health Study in the United States was initially based on 89,538 US nurses aged between 34 and 59, with no history of cancer . These nurses completed an independently validated dietary questionnaire - which included the use of beer, wine, and spirits - in 1980.During the first 4 years of follow-up, 601 cases of breast cancer were diagnosed among cohort members .Among women who consumed 5 to 14 g alcohol daily (about three to nine drinks per week), the age-adjusted relative risk of breast cancer reported was 1.3 (95% confidence interval (CI), 1.1 to 1.7). Consumption of 15 g alcohol or more per day was associated with a relative risk of 1.6 (95% CI, 1.3 to 2.0) and there was evidence of a highly significant increase in risk with increasing reported alcohol consumption (Mantel extension χ for linear trend = 4.2, P <0.0001). Among women without risk factors for breast cancer who were under 55 years of age, the relative risk associated with consumption of 15 g alcohol or more per day was 2.5 (95% CI, 1.5 to 4.2) .