[Meta analysis for relationship between exposure of free silicon dioxide and lung tumor].

Objective: Meta-analysis is applied to process a systematic, comprehensive evaluation on the relationship between silica exposure and lung cancer in order to provide scientific evidences for controlling measures and offer a case for EBOM.
Methods: According to established entrance standards, the collected original articles on silica exposure and lung cancer were classified and put in order, then fixed effects model and random effects model were used which suited to analyze occupational epidemiology and occupational tumor materials, and their correlation intensity were analyzed. First, combined SMR and 95% CI values for case-control study and cohort study were calculated respectively. Then all case-control studies and cohort studies were combined according to different study designs, mixed factors adjusted and stratification analysis processed, and their SMR and 95% CI calculated respectively. In order to lessen bias or errors, fail safe number was calculated.
Results: When combining all the cohort study and all the case-control study respectively, corresponding combination SMR(cohort) = 1.93, 95% CI is 0.55 - 6.92; SMR case = 1.73, 95% CI is 1.01 - 2.99; SMR(sum) = 2.19, 95% CI is 1.45 - 3.31. Statistical test showed a statistically significant relationship lied between silica exposure and lung cancer, with P < 0.05.
Conclusion: Middle intensity relation is drawn between silica exposure and lung cancer incidence at worksite. This result is consistent with a lot of public reports.