Light alcohol drinking and cancer: a meta-analysis

There is convincing evidence that alcohol consumption increases the risk of cancer of the colorectum, breast, larynx, liver, esophagus, oral cavity and pharynx. Most of the data derive from studies that focused on the effect of moderate/high alcohol intakes, while little is known about light alcohol drinking (up to 1 drink/day). We evaluated the association between light drinking and cancer of the colorectum, breast, larynx, liver, esophagus, oral cavity and pharynx, through a meta-analytic approach. We searched epidemiological studies using PubMed, ISI Web of Science and EMBASE, published before December 2010. We included 222 articles comprising similar to 92 000 light drinkers and 60 000 non-drinkers with cancer. Light drinking was associated with the risk of oropharyngeal cancer [relative risk, RR = 1.17; 95% confidence interval (CI) 1.06-1.29], esophageal squamous cell carcinoma (SCC) (RR = 1.30; 95% CI 1.09-1.56) and female breast cancer (RR = 1.05; 95% CI 1.02-1.08). We estimated that similar to 5000 deaths from oropharyngeal cancer, 24 000 from esophageal SCC and 5000 from breast cancer were attributable to light drinking in 2004 worldwide. No association was found for colorectum, liver and larynx tumors. Light drinking increases the risk of cancer of oral cavity and pharynx, esophagus and female breast.