Meta-Analysis on Association Between PM_2.5 Concentrations and Hospital Outpatient Visits for Respiratory Diseases in China

Objective  To assess the association between fine particulate matter (PM_2.5) concentrations and the hospital outpatient visits for respiratory diseases in China.

Method  Based on the online search for publication on the association between PM_2.5 concentrations and hospital outpatient visits for respiratory diseases, Stata 12.0 was used to perform meta-analysis.

Result  Eventually 12 literatures and 13 sets of data were included, covering 8 areas in China. An increase of 10 μg/m³ of PM_2.5 corresponded to a relative risk (RR) of 1.005 (95%CI:1.003-1.007) for respiratory outpatient visits. After excluding heterogeneous data, the RR of respiratory outpatient visits was 1.005 (95%CI:1.003-1.008). Specifically, that for adults and children was 1.004 (95%CI:1.000-1.007) and 1.008 (95%CI:1.003-1.013), respectively; that for Northern China and Southern China was 1.006 (95%CI:1.002-1.009) and 1.004 (95%CI:1.000-1.009), respectively. The RRs of respiratory diseases, asthma, and respiratory infection were 1.005 (95%CI:1.001-1.008), 1.008 (95%CI:1.003-1.013), and 1.001 (95%CI:0.997-1.004), respectively. There was no significant publication bias according to the results of funnel plot and Egger test.

Conclusion  A positive association exists between PM_2.5 concentrations and hospital outpatient visits for respiratory diseases in China.