Light alcohol drinking and cancer: a meta-analysis.
Level 1 - systematic review of randomized trials
Meta-analysis of observational epidemiological studies
PubMed 22910838 · doi:10.1093/annonc/mds337
What was done
Authors searched PubMed, ISI Web of Science, and EMBASE for epidemiological studies published before December 2010 evaluating light alcohol drinking (up to 1 drink/day) and cancer of the oral cavity and pharynx, esophagus, colorectum, larynx, liver, and female breast. They performed a meta-analysis combining 222 articles comprising approximately 92,000 light drinkers and 60,000 non-drinkers with cancer.
What was found
Light alcohol consumption was significantly associated with an increased risk of oropharyngeal cancer (relative risk [RR] = 1.17; 95% 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). The authors estimated that in 2004 worldwide, ~5,000 deaths from oropharyngeal cancer, 24,000 from esophageal SCC, and 5,000 from breast cancer were attributable to light drinking. No association was found for colorectal, liver, or larynx tumors.
Why it matters
This study provides evidence that cancer risk from alcohol is not confined to moderate or heavy intake, demonstrating measurable risk elevations for specific aerodigestive and breast cancers even at low levels of intake.
Limits
The findings rely on observational studies where residual confounding (particularly from smoking in aerodigestive cancers) and misclassification of self-reported alcohol consumption cannot be excluded. The abstract does not specify whether non-drinker reference groups distinguished lifetime abstainers from former drinkers.
Cited by
- supports Very light alcohol drinking (less than half a standard drink per day or under 5 drinks per week) increases the relative risk of breast cancer by around 4%, shifting baseline lifetime risk from 1 in 8 to about 1 in 7.7.
- partial Consuming fewer than 7 drinks per week increases the relative risk for breast cancer by ~4%, colorectal cancer by ~9%, oral and pharyngeal cancer by 13% to 17%, and esophageal cancer and malignant melanoma by 26% to 44%.