Follow-up Of Manganese-exposed Workers Healthy Cohort And Effects Of Occupational Manganese Exposure On Blood Immunological Indicators

ObjectiveBased on the follow-up activity for the manganese-exposed workers healthy cohort study（MEWHC）,the epidemiological data,the results of occupational health examination,air concentration of Mn in workplaces and the detection results of blood immunological indicators were obtained.All the data were used to describe the epidemiological characteristics of the manganese-exposed workers and to explore the effects of occupational manganese exposure on blood immunological indicators.Methods1.The participants recruited in the cohort were followed up,and the new research objects that meet the inclusion criteria were continued recruited in2017.We used the data of epidemiological questionnaires,included the demographic information,the life habits,the history of medication,disease and occupation,the result of occupational health examination,included pulmonary function,liver function and ECG,and the bio-samples,included serum,plasma,bloodcell,urine,faeces,hairandnails,todescribethe epidemiological characteristics of the manganese-exposed workers by using the method of the cross-sectional study.2.The turbidimetric inhibition immuno assay was adopted to detect the immunological indicators in serum collected from the manganese-exposed workers,included IgG,IgA,IgM,Ig E,C3,C4,CRP.And the inflammatory markers in blood,included WBC,LYMPH,MONO,NEUT,EO,BASO were obtained from the epidemiological database of MEWHC.According to PC-TWA（0.15mg/m³）,the occupational exposure limits for Manganese in Workplaces stipulated by GBZ2.1-2007,total of 496 workers were divided into internal control group and exposure group.Thus,the effects of occupational manganese exposure onbloodimmunological indicators wasanalyzed using idependent-samples t test,Wilcoxon rank sum test,analysis of covariance（ANOVA）and multivariable linear regression model.Results1.A total of 828 manganese-exposed workers were investigated in 2017.700 workers were previously recruited before 2017 and 128 workers were new recruits in 2017.The follow-up rate was 73.92%.The 828 manganese-exposed workers were comprised 559 male（67.51%）and 269 female（32.49%）.The average age was 44.03±7.08 and the average seniority was 19.69±8.86.In addition,the proportion of smelters was 25.36%in all types of work,with the Mn-TWA was 0.2043 mg/m³,while the Human crushing worker still have the highest Mn-TWA（0.3085 mg/m³）.2.The results of occupational examination were analyzed stratified by sex.In the male workers,compared with the internal control group,the level of MVV%pred in pulmonary function test was significantly increased in exposure group（P<0.05）,the level of ALT in liver function test was significantly increased in exposure group（P<0.05）,the level of CK in myo-cardial enzymonram examination was also significantly increased in exposure group（P<0.05）,and the QRS duration,QTC interval and RV5 in ECG examination were also significantly increased in exposure group（P<0.05）.In the female workers,the pulmonary function test were not significant differences between the internal control group and exposure group（P>0.05）.And compared with the internal control group,the level of AST in liver function test was significantly increased in exposure group（P<0.05）,the levels of CK-MB,LD and?-HBD in myo-cardial enzymonram examination were also significantly increased in exposure group（P<0.05）,the QRS duration and RV5 in ECG examination were also significantly increased in exposure group（P<0.05）.The abnormality rate of the pulmonary function,liver function,myo-cardial enzymonram,GLU,BP,ECG and urine routine were 10.51%,14.86%,30.31%,17.27%,29.47%,17.15%,37.20%,respectively.Besides,the abnormality rate of myo-cardial enzymonram in exposure group was higher than the abnormality rate of internal control group（P<0.05）,while there were not significant differences for abnormality rate of other physical examination items between the internal control group and exposure group.3.Comparing the concentrations of immunological indicators between the internal control group and the exposed group,the results showed that the concentrations of IgG,IgM,C3 were significantly decreased and the concentration of EO was significantly increased in the exposed group（P<0.05）.After stratification by gender,there were significant differences for the concentrations of C3 and EO between the internal control group and the exposed group in male workers（P<0.05）.After stratification by smoking status,there was significant difference for the concentrations of C3 between the internal control group and the exposed group in smoker（P<0.05）,and there was significant difference for the concentrations of EO between the internal control group and the exposed group in non-smoker（P<0.05）.Besides,there was significant interaction between manganese exposure and smoking in both the levels of C3 and EO(P_interaction<0.05).After stratification by BMI,the results showed that there were significant differences for the concentrations of C3 and EO between the internal control group and the exposed group in the normal group of BMI（P<0.05）.The results of multiple linear regression analysis between Mn-TWA and IgG,IgM,C3,EO showed that there were negative correlation between the concentration of C3 and Mn-TWA（Beta=-0.102,P=0.018）and positive correlation between the level of EO and Mn-TWA（Beta=0.096,P=0.033）,while there were not correlation between Mn-TWA with IgG,IgM（P>0.05）.Conclusions1.The pulmonary function test,liver function test,myo-cardial enzymonram examination and ECG were conducted on manganese-exposed workers in follow-up activities,and the changes of systemic function would be monitored and the health damage effect of human body can be explored.2.Manganese exposure can lead to the decrease of C3 level and the increase of EO level.Mn-TWA was negatively correlated with the level of C3and positively correlated with the level of EO,suggesting that occupational manganese exposure may affect the levels of body immunological indicators.