Alcohol drinking and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.
BACKGROUND
It remains unclear whether alcohol drinking is causally associated with colorectal cancer. On the basis of a systematic review of epidemiological evidence, we evaluated this association among the Japanese population, who may be more susceptible to alcohol-related diseases than Western populations.


METHODS
Original data were obtained from searches of MEDLINE using PubMed, complemented with manual searches. The evaluation of associations was based on the strength of evidence and the magnitude of association, together with biological plausibility as previously evaluated by the International Agency for Research on Cancer.


RESULTS
We identified 5 cohort studies and 13 case-control studies. A moderate or strong positive association was observed between alcohol drinking and colon cancer risk in all large-scale cohort studies, with some showing a dose-response relation, and among several case-control studies. The risk of colon or colorectal cancer was increased even among moderate drinkers consuming <46 g of alcohol per day, levels at which no material increase in the risk was observed in a pooled analysis of Western studies. A positive association with rectal cancer was also reported, but it was less consistent, and the magnitude of the association was generally weaker compared with colon cancer.


CONCLUSIONS
We conclude that alcohol drinking probably increases the risk of colorectal cancer among the Japanese population. More specifically, the association for the colon is probable, whereas that for the rectum is possible.
Mizoue
Tetsuya
T
Department of Preventive Medicine, Kyushu University, Fukuoka, Japan. mizoue@ri.imcj.go.jp
Tanaka
Keitaro
K
Tsuji
Ichiro
I
Wakai
Kenji
K
Nagata
Chisato
C
Otani
Tetsuya
T
Inoue
Manami
M
Tsugane
Shoichiro
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects; D016022:Case-Control Studies; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000453:epidemiology; D012307:Risk Factors