[Meta-analysis study on occupational wood dust exposure association with chronic obstructive pulmonary disease]

Objective: To clarify the association between occupational exposure to wood dust and chronic obstructive pulmonary disease risk by a meta-analysis. Methods: A systematic search of the studies was conducted using 3 English databases (Pubmed, Embase, and Cochrane library) and 3 Chinese databases (CNKI, WanFang, and VIP) before March 2019. The following key words was used: 1) wood, 2) hardwood, 3) softwood, 4) saw, 5) dust, 6) chronic obstructive pulmonary disease, 7) chronic obstructive airway disease, 8) lung function. A quality score was evaluated by Newcastle-Ottawa Scale, NOS (Wells, 2012). Pooled effect value with 95% confidence interval (CI) was calculated using fixed-effect model (Heterogeneity test I(2)<25%) or random-effect model (Heterogeneity test I(2)≥25%). Meta-regression was used to explore heterogeneous source. Sensitivity analysis was used to verify the stability of the results. Publication bias was assessed by Egger＇s test. Fill and trim method was used to correct the pool effect value with 95%CI for studies which wit publication bias. The TSA threshold was calculated by the O＇Brien-Fleming loss function in the TSA data. The studies were evaluated based on the accrued information size (AIS) . Results: A total of 9 studies were included in the analysis. The occupational exposure to wood dust was not significantly associated with increased chronic obstructive pulmonary disease risk (ES=1.01, 95%CI: 0.856-1.194). TSA showed that the cumulative Z-value curve neither gone beyond the traditional (Z=1.96) threshold line, nor exceed the TSA threshold, but has reached the expected amount of information. This result was consistent with the meta-analysis. Conclusion: This study does not yet consider that COPD is associated with occupational wood dust exposure.