The Average Treatment Effect For The Treated Of Nickel Smelting Workers' Exposure Effect:A Propensity Score Matching Study

OBJECTIVEThe aim of this study was to balance the different background distribution of nickel smelting workers and office workers group using propentsitiy score matching,and obtain the average treatment effect for the treated of nickel smelting environment exposure,to see the effect of oxidative damage,DNA damage and repair,epigenetics and embryo lung development related biomarker induced by nickel smelting environment,and provide a possible mechanism of nickel compound carcinogenesis.MethodUsing average treatment effect model and propensity score matching,the average treatment effect for the nickel smelting worker group(ATT)were calculated.Then the correlationship between nickel smelting exposure years and ATT of embryo lung development biomarkers and the rest biomarkers were analysed.RESULTS1.Exposure to nickel smelting environment may lead to the expression change of oxidative damage biomarkers.The exposure time was significantly corelated with the ATT of SOD.And the ATT of MDA in the 6 employment-year groups showed no statistical difference.2.Nickel smelting environment exposure may lead to the expression change of DNA damage and repair biomarkers.The ATT of 8-OHDG in 6 employment years groups showed a statistical difference.While the analysis on the ATT of PARP and hOGG1 showed no statistical difference.3.Exposure to nickel smelting environment may modify the expression of epigenetics biomarkers.The exposure time was linked to the ATT of HDAC and H3K27me3.And the ATT of HP1,HP1,DNMT1 and H3K4me3 in the 6 employment-year groups showed no statistical difference.4.Nickel smelting environment exposure may result in the exposure change of embryo lung development biomarkers.The exposure time was linked to the ATT of pSmad2 and Nkx2.1.The ATT of STAT5,HHIP showed a statistical difference in the 6 employment years groups,while the ATT of PI3K,SHH and Cited2 did not.CONCLUSIONS1.Propensity score matching based on covariates can be used for weakening the selection bias existed in observational experiments.2.Exposed to the nickel smelting environment would lead to the expression change of oxidative damage,DNA damage and repair,epigenetics and embryo lung development related biomarkers.3 TGF-? signal pathway biomarkers pSmad2 and Nkx2.1 would participate the carcinogenic mechanism induced by nickel exposure.4.Embryo lung development biomarker Cited2,Hedgehog signal pathway biomarkers HHIP,PI3K and Shh would not involve in the nickel induced lung cancer.5.Nickel smelting environment exposure mould regulate other gene's expression through epigenetics way,such as embryo lung development genes.