American Journal of Epidemiology Advance Access originally published online on April 11, 2008
American Journal of Epidemiology 2008 167(12):1397-1406; doi:10.1093/aje/kwn073
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Alcohol Drinking and Colorectal Cancer in Japanese: A Pooled Analysis of Results from Five Cohort Studies
1 Department of Epidemiology and International Health, Research Institute, International Medical Center of Japan, Tokyo, Japan
2 Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan
3 Department of Preventive Medicine/Biostatistics and Medical Decision Making, Graduate School of Medicine, Nagoya University, Nagoya, Japan
4 Department of Epidemiology and Preventive Medicine, Graduate School of Medicine, Gifu University, Gifu, Japan
5 Division of Epidemiology, Department of Public Health and Forensic Medicine, Graduate School of Medicine, Tohoku University, Sendai, Japan
6 Department of Public Health, Graduate School of Medicine, Gunma University, Maebashi, Japan
7 Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga, Japan
8 Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan
9 Division of Clinical Trials, National Center for Geriatrics and Gerontology, Aichi, Japan
Correspondence to Dr. Tetsuya Mizoue, Department of Epidemiology and International Health, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan (e-mail: mizoue{at}ri.imcj.go.jp).
Received for publication November 5, 2007. Accepted for publication February 28, 2008.
Colorectal cancer is an alcohol-related malignancy; however, the association appears to be stronger among Asian populations with a relatively high prevalence of the slow-metabolizing aldehyde dehydrogenase variant. To examine the association between alcohol consumption and colorectal cancer in Japanese, the authors analyzed original data from five cohort studies that measured alcohol intake using validated questionnaires at baseline. Hazard ratios were calculated in the individual studies, with adjustment for a common set of variables, and then combined using a random-effects model. During 2,231,010 person-years of follow-up (ranging variously from 1988 to 2004), 2,802 colorectal cancer cases were identified. In men, multivariate-adjusted pooled hazard ratios for alcohol intakes of 23–45.9 g/day, 46–68.9 g/day, 69–91.9 g/day, and 
92 g/day, compared with nondrinking, were 1.42 (95% confidence interval (CI): 1.21, 1.66), 1.95 (95% CI: 1.53, 2.49), 2.15 (95% CI: 1.74, 2.64), and 2.96 (95% CI: 2.27, 3.86), respectively (p for trend < 0.001). The association was evident for both the colon and the rectum. A significant positive association was also observed in women. One fourth of colorectal cancer cases in men were attributable to an alcohol intake of 23 g/day. An alcohol-colorectal cancer association seems to be more apparent in Japanese than in Western populations. Whether this difference can be ascribed to genetic or environmental factors needs to be clarified.
alcohol drinking; colonic neoplasms; colorectal neoplasms; rectal neoplasms
Abbreviations: CI, confidence interval; HR, hazard ratio; JACC, Japan Collaborative Cohort Study; JPHC, Japan Public Health Center-based Prospective Study