Fish consumption and risk of gastrointestinal cancers: a meta-analysis of cohort studies.
OBJECTIVE
To assess quantitatively the relationship between fish intake and the incidence of gastrointestinal cancers in a meta-analysis of cohort studies.


METHODS
We searched MEDLINE, Embase, Science Citation Index Expanded, and the bibliographies of retrieved articles. Prospective cohort studies were included if they reported relative risks (RRs) and corresponding 95% confidence intervals (CIs) of various cancers with respect to fish intake. When RRs were not available in the published article, they were computed from the exposure distributions. Two investigators extracted the data independently and discrepancies were resolved by discussion with a third investigator. We performed random-effect meta-analyses and meta-regressions of study-specific incremental estimates to determine the risk of cancer associated with a 20-g/d increment of fish consumption.


RESULTS
Forty-two studies, comprising 27 independent cohorts, met our inclusion criteria. The studies included 2325040 participants and 24115 incident cases of gastrointestinal cancer, with an average follow-up of 13.6 years. Compared with individuals who did not eat, or seldom ate, fish, the pooled RR of gastrointestinal cancers was 0.93 (95%CI: 0.88-0.98) for regular fish consumers, 0.94 (0.89-0.99) for low to moderate fish consumers, and 0.91 (0.84-0.97) for high fish consumers. Overall, a 20-g increase in fish consumption per day was associated with a 2% reduced risk of gastrointestinal cancers (RR = 0.98; 95%CI: 0.96-1.01). In subgroup analyses, we noted that fish consumption was associated with reduced risk of colorectal (RR = 0.93; 95%CI: 0.87-0.99; P < 0.01), esophageal (RR = 0.91; 95%CI: 0.83-0.99; P < 0.05) and hepatocellular cancers (RR = 0.71; 95%CI: 0.48-0.95; P < 0.01).


CONCLUSIONS
This meta-analysis suggested that fish consumption may reduce total gastrointestinal cancer incidence. Inverse relationships were also detected between fish consumption and specific types of cancers.
Xiao-Feng Yu, Jian Zou, Jie Dong, Department of Gastroenterology, Huadong Hospital, Fudan University, Shanghai 200040, China.
Xiao-Feng
XF
Yu
Xiao-Feng Yu, Jian Zou, Jie Dong, Department of Gastroenterology, Huadong Hospital, Fudan University, Shanghai 200040, China.
Jian
J
Zou
Xiao-Feng Yu, Jian Zou, Jie Dong, Department of Gastroenterology, Huadong Hospital, Fudan University, Shanghai 200040, China.
Jie
J
Dong
D000818:Animals; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects; D005399:Fishes; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D008113:Liver Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016017:Odds Ratio; D065840:Protective Factors; D018570:Risk Assessment; D012307:Risk Factors; D017747:Seafood
Cancer prevention; Diet; Fish intake; Gastrointestinal cancer