Cohort studies on cancer mortality of Digestive system among workers exposed to Asbestos: a meta-analysis

摘要

Objective To determine whether excessive risk of digestive system cancer exits among workers exposed to asbestos by applying a meta-analysis technique. Methods All data meeting the criteria of cohort studies on cancer mortality of digestive system among workers exposed to asbestos would incorporate into the meta-analysis. The pooled standardized mortality ratios (SMRs) and their corresponding 95% confidence intervals (CIs) for main cancer sites of digestive system were calculated using two approaches of unweighted ratio and random effects model. The heterogeneity and its sources of the results were examined with a Q-statistic and Z-score test. Results 69 asbestos-exposed cohorts were summarized. The significantly elevated meta-SMRs for all deaths (1.16), all cancers (1.42), cancer of digestive system (1.15) and cancer of stomach (1.20) among workers exposed to chrysotile alone or both chrysotile and amphibole mixed asbestos were observed. Meta-SMR for cancer of stomach was signiificant elevantion among asbestos cement workers (1.27), miners and millers (1.21) and insulators (2.13). The pooled analysis results for other cancers at other sites of digestive system including cancer of oesophagus, cancer of intestine, cancer of colon, cancer of rectum and cancer of liver were all not significantly elevated (P＞0.05). The sensitivity analysis showed that the results from this meta-analysis were robust. Conclusions There were excessive risks of stomach cancer among workers exposed to asbestos, and likely no convincing indication of an etiological association between asbestos exposure and cancers at other sites of digestive system.