Inverse relationship between moderate alcohol intake and rectal cancer: Analysis of the North Carolina colon cancer study

Background: The relationship between alcohol intake and rectal cancer is uncertain. Objective: We sought to evaluate whether alcohol consumption is associated with distal colorectal cancer and rectal cancer specifically. Design: Data on alcohol intake were examined from the North Carolina Colon Cancer Study, a population-based case-control study of distal colorectal cancer. Setting: This study encompassed 33 counties in the central and eastern part of North Carolina. Patients: Cases had adenocarcinoma of the rectum, rectosigmoid, and sigmoid colon. Controls were frequency-matched on age, race, and sex. Interventions: Demographic and dietary intake data were collected with use of a validated questionnaire. Main outcome measures: Logistic regression was used to estimate odds ratios for the relationship between alcohol consumption and distal colorectal cancer. Results: Included in the study were 1033 cases and 1011 controls. The odds ratio for rectal cancer comparing any vs no alcohol intake was 0.73 (95% CI 0.60, 0.90),adjusted for age, sex, race, smoking status, obesity, education, red meat intake, use of nonsteroidal anti-inflammatory medications, and family history of colorectal cancer. The odds ratio for moderate alcohol (≥14 g/day) was 0.66 (95% CI 0.53, 0.82), whereas the odds ratio for heavy alcohol (≤14 g/day) was 0.93 (95% CI 0.70, 1.23). Moderate beer and wine intakes were also inversely associated with distal colorectal cancer: odds ratios 0.76 (95% CI 0.60, 0.96) and 0.69 (95% CI 0.56, 0.86). Limitations: This was a retrospective, observational study. Residual confounding is possible. Conclusions: In this study, moderate alcohol intake (especially wine) was inversely associated with distal colorectal cancer.