Meta-analysis of 16 studies of the association of alcohol with colorectal cancer

Alcohol consumption is an established risk factor for colorectal cancer (CRC). However, while studies have consistently reported elevated risk of CRC among heavy drinkers, associations at moderate levels of alcohol consumption are less clear.
Researchers performed a combined analysis of 16 studies of CRC to examine the shape of the alcohol-CRC association, investigate potential effect modifiers of the association, and examine differential effects of alcohol consumption by cancer anatomic site and stage. Information on alcohol consumption was collected for 14,276 CRC cases and 15,802 controls from five case-control and 11 nested case-control studies of CRC.
Study-specific results were pooled using fixed- effects meta-analysis. Compared to non-/ occasional drinking (≤1 g/day), light/moderate drinking (up to 2 drinks/day) was associated with a decreased risk of CRC (OR: 0.92, 95% CI: 0.88- 0.98), heavy drinking (2-3 drinks/day) was not significantly associated with CRC risk (OR: 1.11, 95% CI: 0.99-1.24) and very heavy drinking (more than 3 drinks/day) was associated with a significant increased risk (OR: 1.25, 95% CI: 1.11-1.40). The researchers observed no evidence of interactions with lifestyle risk factors or of differences by cancer site or stage.
These results provide further evidence that there is a J-shaped association between alcohol consumption and CRC risk. This overall pattern was not significantly modified by other CRC risk factors and there was no effect heterogeneity by tumor site or stage.
Source: Meta-analysis of 16 studies of the association of alcohol with colorectal cancer. McNabb S, Harrison TA, Albanes D, Berndt SI, Brenner H, et al. Int J Cancer. 2019 Apr 29.