| Objective: 1.To investigate the effects of different noise exposure levels on the cardiovascular system(hypertension,electrocardiogram abnormality)among the occupational population based on a retrospective cohort.2.To evaluate whether there was an interactive effect between occupational noise exposure and other exposures(ambient temperature or harmful gas exposure),and to explore the relationship between exposure time,work type and cardiovascular system.3.To reveal the high-risk occupational population of cardiovascular disease,and to provide scientific basis for preventing cardiovascular disease and protecting occupational workers effectively.Methods: 1.Research subject.In this study,retrospective cohort study designs were used.The largest chemical enterprise in Anhui province of China was selected as our study site,and all registered employees exposed to occupational noise were selected as our study population.On the basis of occupational health examination,occupational health examination results from 2014 to 2018 were collected,including medical information such as hypertension or abnormal changes in electrocardiogram diagnosed by doctors.2.Environmental monitoring.In this study,occupational harmful factors such as environmental noise and high temperature were monitored according to “occupational exposure limits of hazardous factors in the workplace”(GBZ2.2-2007).According to the noise exposure assessment,selected subjects were divided into high-,intermediate-,and low-exposure groups.The ambient temperature is graded(Grade I-IV)according to the high temperature operation classification standard.3.Health investigation.In thisstudy,personal information of worker were obtained through face-to-face questionnaires and excerpted from occupational health records,including the personal basic situation,living habits and occupational history of workers.4.Statistical analysis.Epi Data 3.1 was used to establish the database,and SPSS 23.0 was used to establish the Cox regression model to analyze exposure-effect relationship.Chi-square test was applied to compare the constitution of cigarette usage,alcohol intake,regular exercise,marriage status,educational level,and family histories among the three exposure groups.Stratified analysis was used to screen the exposed high-risk groups.Results: 1.During the 8587 person-years of follow-up,580 cases were diagnosed with hypertension and 1024 cases were diagnosed with electrocardiogram abnormality by the end of the follow-up period in 2018.2.Compared with the low-exposure group,workers exposed to occupational noise ?80 d B(A)and 70-80 d B(A)were at risk for hypertension,respectively,with HR of 1.85(95%CI: 1.36,2.52)and 1.29(95%CI: 1.03,1.60).Male operators with noise exposure between 15 and 25 years were at high risk for hypertension.3.Compared with the low-exposure group,occupational exposure to noise levels above 80 d B(A)could increase the risk of electrocardiogram abnormality(HR=1.31,95%CI: 1.06,1.63),especially for male operators who have been exposed to noise for 25 to 35 years.4.In addition,workers exposed to both high temperature and occupational noise ?80 d B(A)exhibited a further increased risk of hypertension(HR =8.98,95%CI: 3.25,24.86).Ammonia exposure was a risk factor of hypertension while the interaction analysis with occupational noise were negative.Conclusion: 1.Occupational noise exposure can increase the risk of cardiovascular disease in occupational population.2.There is an interactive effect between occupational noise exposure and high temperature.Exposure to both high temperature and occupational noise increased the risk of hypertension.3.Workers exposed tooccupational noise for more than 15 years may be high-risk groups,which need to be focused on and protected. |
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