Meat consumption and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.
OBJECTIVE
The association between meat consumption and colorectal cancer remains inconsistent among Asians. The present study systematically evaluated and meta-analyzed epidemiologic studies on the association between consumption of total and specific meats and colorectal cancer risk among Japanese.


METHODS
Original data were obtained from MEDLINE searched using PubMed or from searches of the Ichushi database, complemented with manual searches. The associations were evaluated based on the strength of evidence, the magnitude of association and biologic plausibility. A meta-analysis was performed according to total meat, red and processed meat as well as poultry and site-specific cancers.


RESULTS
Six cohort studies and 13 case-control studies were identified. In cohort studies, most investigations found no association between total meat consumption and colon/rectal cancer, and several studies showed a weak-to-moderate positive association of red meat and processed meat consumption with colon/rectal cancer. The majority of case-control studies showed no association between total meat consumption and colon and rectal cancer; however, several ones reported a weak-to-strong positive association of red and processed consumption with colon and rectal cancer. In meta-analysis, the summary relative risks (95% confidence interval) for the highest versus lowest categories of red meat consumption were 1.16 (1.001-1.34) and 1.21 (1.03-1.43) for colorectal and colon cancer, respectively, and those for processed meat consumption were 1.17 (1.02-1.35) and 1.23 (1.03-1.47) for colorectal and colon cancer, respectively. Poultry consumption was associated with lower risk of rectal cancer; summary relative risk (95% confidence interval) was 0.80 (0.67-0.96).


CONCLUSIONS
High consumption of red meat and processed meat possibly increases risk of colorectal cancer or colon cancer among the Japanese population.
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo.
Ngoc Minh
NM
Pham
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo mizoue@ri.ncgm.go.jp.
Tetsuya
T
Mizoue
Department of Preventive Medicine, Saga University Faculty of Medicine, Saga.
Keitaro
K
Tanaka
Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai.
Ichiro
I
Tsuji
Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo.
Akiko
A
Tamakoshi
Department of Preventive Medicine, Kyushu University Faculty of Medical Sciences, Fukuoka.
Keitaro
K
Matsuo
Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya.
Kenji
K
Wakai
Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu.
Chisato
C
Nagata
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo AXA Department of Health and Human Security, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Manami
M
Inoue
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo.
Shoichiro
S
Tsugane
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo.
Shizuka
S
Sasazuki
D000818:Animals; D044466:Asian People / Q000706:statistics & numerical data*; D016022:Case-Control Studies; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000209:etiology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D005247:Feeding Behavior; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008460:Meat / Q000009:adverse effects / Q000706:statistics & numerical data; D008461:Meat Products / Q000009:adverse effects / Q000706:statistics & numerical data; D011200:Poultry; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000209:etiology; D012306:Risk
Japanese; colorectal cancer; epidemiology; meat; systematic review