The effect of silica exposure on the risk of lung cancer: A meta-analysis

Lung cancer is an incurable disease with an increased mortality rate caused by the inhalation of dust-containing crystalline silica particles. Silica exposure is one of the most important occupational hazards in the world. Whether the association between silica exposure and lung cancer is because of the fibrotic process or to the effect of respirable silica itself is unclear. The International Agency for Research on Cancer (IARC) classified silica as a human lung carcinogen. The opinion of lung cancer is a question that has been addressed in this review. Three electronic databases, including MEDLINE, Scopus, and Web of Science, were used to search for relevant literature from 2000 to 2022. To evaluate the relationship between exposure to silica and developing lung cancer, we performed a meta-analysis using the random-effects model. For each study, the overall odds ratio (OR), relative risk (RR) with 95% confidence intervals (CI), and p values were calculated. An extensive database search resulted in the selection of 20 (case-control and nested case-control studies were selected) out of 527 studies. Among the 20 selected studies, 7 studies showed a significant association between silica exposure and an increased risk of lung cancer. Further analysis showed that among the selected studies, six studies showed a significant correlation between combined exposure to silica and smoking with an increased risk of lung cancer. The data from the present study showed that smoking habits increased the impact of silica exposure on the initiation of lung carcinogenesis in exposed workers.