Crystalline silica is a widely used industrial material that is readily available worldwide, and is one of the most common types of particulate mineral pollutants. It has been classified as a group 1 human carcinogen of the respiratory system; however, whether it is linked to gastric cancer remains uncertain. We conducted a systemic review and meta-analyses to search for evidence of the relationship between gastric cancer and occupational exposure to crystalline silica. We searched for articles on occupations involving silica exposure and gastric cancer studies up to December 2014. Pooled-risk estimates of the association between occupational crystalline silica exposure and risk of gastric cancer were calculated by a random effects model. Metaregression analyses of industry type and histological confirmation status, study design and industrial subgroup analyses were performed. 29 articles, including 9 case–control and 20 cohort studies, were analysed. The overall summary effects size was 1.25 (95% CI 1.18 to 1.34) for the association of occupational silica exposure with gastric cancer. Both heterogeneity and publication bias were partially attenuated after subgroup analyses. Heterogeneity of studies was attenuated after metaregression by industry. Higher overall effects were observed in the mining and foundry industries. We found a significant relationship between occupational crystalline silica exposure and gastric cancer. Our results were strengthened by various subgroup analyses and, considering the biological plausibility of our premise, further studies are required to better understand this association.
- crystalline silica
- gastric cancer
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Contributors WL searched the articles, analysed the data and drafted the manuscript. Y-SA designed the study, interpreted the data and revised the manuscript. SL and BMS searched the articles and drafted the manuscript. SH searched the articles and revised the manuscript. J-HY is the corresponding author of this article. He suggested the study design, interpreted the data and revised the manuscript.
Disclaimer All aspects of the study design, data analysis and manuscript writing were independent of the funders.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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