Original Article
Effect of endotoxin exposure on lung cancer risk in cotton textile mills and agriculture: a meta-analysis
Abstract
Background: To evaluate the relationship between occupational exposure to endotoxin and the risk of lung cancer among workers in cotton textile mills and agriculture where high levels of endotoxin are contained.
Methods: Relevant studies were searched in PubMed, Embase, the Cochrane library and Chinese databases before March, 2015. Sources of the heterogeneity were identified through Galbraith radial plots and subgroup analyses. We utilized random effects model to estimate the overall risk and 95% confidence interval (CI).
Results: Fourteen cotton textile studies and twenty agricultural studies were finally included in this meta-analysis. The pooled relative risk (RR) between endotoxin exposure and lung cancer was 0.94 (0.79–1.11) for textile workers and 0.70 (95% CI, 0.59–0.84) for agricultural workers. Heterogeneity was existent among agriculture studies (I2 97.7%, P=0.000). Significant protective effects were showed in several subgroups of cotton textile studies as follows: case-control study, 0.70 (95% CI, 0.58–0.84); adjusted for smoking, 0.79 (95% CI, 0.66–0.95); USA, 0.62 (95% CI, 0.47–0.83); morbidity as outcome, 0.84 (95% CI, 0.73–0.97); follow up 11–20 years, 0.89 (95% CI, 0.80–0.99). For agriculture studies, two subgroups by case-control design (RR 1.42; 95% CI, 1.06–1.91) and Asian region (RR 1.74; 95% CI, 1.25–2.43) significantly altered the protective effect of endotoxin.
Conclusions: This meta-analysis supported that exposure to high concentrations of endotoxin is associated with decreased lung cancer risk in cotton textile mills and agricultural work.
Methods: Relevant studies were searched in PubMed, Embase, the Cochrane library and Chinese databases before March, 2015. Sources of the heterogeneity were identified through Galbraith radial plots and subgroup analyses. We utilized random effects model to estimate the overall risk and 95% confidence interval (CI).
Results: Fourteen cotton textile studies and twenty agricultural studies were finally included in this meta-analysis. The pooled relative risk (RR) between endotoxin exposure and lung cancer was 0.94 (0.79–1.11) for textile workers and 0.70 (95% CI, 0.59–0.84) for agricultural workers. Heterogeneity was existent among agriculture studies (I2 97.7%, P=0.000). Significant protective effects were showed in several subgroups of cotton textile studies as follows: case-control study, 0.70 (95% CI, 0.58–0.84); adjusted for smoking, 0.79 (95% CI, 0.66–0.95); USA, 0.62 (95% CI, 0.47–0.83); morbidity as outcome, 0.84 (95% CI, 0.73–0.97); follow up 11–20 years, 0.89 (95% CI, 0.80–0.99). For agriculture studies, two subgroups by case-control design (RR 1.42; 95% CI, 1.06–1.91) and Asian region (RR 1.74; 95% CI, 1.25–2.43) significantly altered the protective effect of endotoxin.
Conclusions: This meta-analysis supported that exposure to high concentrations of endotoxin is associated with decreased lung cancer risk in cotton textile mills and agricultural work.
