Fish consumption and risk of esophageal cancer and its subtypes: a systematic review and meta-analysis of observational studies.

BACKGROUND/OBJECTIVES: Inconsistent results regarding the association between fish intake and risk of subtypes of esophageal cancer (EC), esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC), have been reported. To provide a quantitative assessment of this association, we summarized the evidence from observational studies.

SUBJECTS/METHODS: Relevant studies were identified in MEDLINE and EMBASE until 31 May, 2012. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were pooled with a random-effects model. Between-study heterogeneity was assessed using the Cochran's Q and I(2) statistics.

RESULTS: A total of 24 studies (21 case-control and 3 cohort studies) were included in this systematic review and meta-analysis. The SRRs of ESCC were 0.81 (95% CI: 0.66-0.99) for those in the highest fish consumption category compared with those in the lowest consumption category, with significant heterogeneity among studies (P(heterogeneity)=0.007, I(2)=51.9%). Subgroup analysis suggested that a weak association between fish consumption and ESCC risk was shown in hospital-based case-control studies, but not in population-based case-control or cohort studies. According to high vs low analysis, fish consumption had no relationship with EAC risk (SRR=0.86, 95% CI: 0.61-1.22).

CONCLUSIONS: Our results suggest that fish consumption is not appreciably related to risk of both ESCC and EAC.