Association between butchers and cancer mortality and incidence: A systematic review and meta-analysis

BACKGROUND: In this study, we evaluated whether increased risks of mortality and cancer incidence exist among butchers worldwide. To achieve this goal, we conducted a systematic review and meta-analysis to investigate the correlations of the risks of cancer death and incidence with male and female butchers. METHODS: We obtained data by performing a comprehensive literature search in several databases for eligible studies published before March 2017. Multivariable-adjusted standardized mortality ratios (SMRs) and odds ratio (OR), as well as associated 95% confidence intervals (CIs) and those by subgroups, were extracted and pooled. RESULTS: A total of 17 observational studies comprising 397,726 participants were included in the meta-analysis. The butcher occupation was not associated with all-cancer mortality risk, with pooled overall SMRs of 1.07 (95% CI 0.96-1.20). However, the pooled ORs revealed that butchers hold an elevated risk of total cancer incidence (OR, 1.51; 95% CI, 1.33-1.73). No proof of publication bias was obtained, and the findings were consistent in the subgroup analyses. CONCLUSION: Our results suggest that working as butchers did not significantly influence all-cancer mortality risk but significantly contributed to elevated all-cancer incidence risk. Nevertheless, well-designed observational studies on this topic are necessary to confirm and update our findings.