Study On The Combined Exposure To Harmful Factors And Abnormal Peripheral Blood Counts Of Workers In Benzene-related Enterprises In Guangdong Province

ObjectivesTo understand the occupational exposure to harmful factors in the workplace,the number of workers with occupational exposure to harmful factors and the rate of occupational medical examination in benzene-related enterprises in Guangdong Province.Explore the hazards of noise and combined exposure to benzene and noise on the hematological system.To find the sensitive blood cell indicators of occupational benzene poisoning.MethodsBenzene-related enterprises in Guangdong Province that have declared occupational hazards test and occupational medical examination from 2019 to 2022were selected.The basic situation of enterprises,the detection of harmful factors in enterprises and the occupational health examination of enterprises were investigated.The detection rate of harmful factors,the rate of exposure to harmful factors,the rate of health examination in enterprises and the rate of health examination of occupational workers were calculated and compared.In the cross-sectional study,15,865 workers exposed to benzene and/or noise who underwent occupational health examination in Guangdong Province in 2018were selected as the research objects,including 9,421 workers in the benzene exposure group,4,086 workers in the noise exposure group,and 2,358 workers in the combined exposure group.Theχ²test,nonparametric test,and logistic multi-factor regression analysis were applied to analyze the abnormal peripheral blood cell count of workers and the influence of age,gender,length of service,enterprise scale and economic type on the abnormal rate of peripheral blood cell count of workers.A retrospective cohort study was conducted on two typical enterprises selected from the population of the second part of the cross-sectional study.The workers who underwent occupational health examination in a company in Shaoguan City and a company in Heyuan City from 2016-2020 in Guangdong Occupational Disease Prevention and Control Hospital were selected as the research objects.A total of 836people entered the occupational health examination cohort,including 55 in 2016,438in 2017 and 343 in 2018.The shortest follow-up time was 2 years and the longest was4 years.The time trend test method was used to analyze whether there was a fixed trend in the annual change curve of the mean value of peripheral blood cell counts in workers.According to the prior tests strategy,Bonferroni multiple comparisons was used to compare the annual differences in the mean values of peripheral blood cell counts.The relationship between each variable and each peripheral blood count was analyzed by applying univariate generalized estimating equations（GEE）with whether or not each peripheral blood count abnormality was detected as the dependent variable and the indicators of gender,age,and type of exposure to harmful factors（benzene exposure alone,benzene and other factors combined）as the independent variables,respectively.ResultsThere are benzene operation enterprises in 21 cities of Guangdong Province,most of which are domestic enterprises（81.6%）,and the scale of enterprises is mainly small（53.0%）and micro（31.0%）enterprises.The exposure rate of harmful factors was 22.1%,the occupational health examination of enterprises was 72.2%,and the prevalence of occupational diseases was 1.6%.Many benzene-related enterprises in Guangdong Province are also exposed to occupational disease hazards such as dust,other chemical poisons,noise and radiation,etc.In the survey,it was found that the proportion of exposure to noise in the working environment of benzene-related enterprises was high,and the medical examination rate of workers was only 63.0%.In the cross-sectional study,the abnormal rates of red blood cell count（RBC）and hemoglobin content（Hb）in the noise exposure group were higher than those in the benzene exposure group and the combined exposure group(χ_RBC²=40.29,χ_Hb²=44.66,P<0.05).Compared with the combined exposure of benzene and noise,the OR（95%CI）for abnormal Hb in noise-exposed workers was 1.352（1.120～1.633）.The abnormal rates of Hb and platelet count（PLT）in women were higher than those in men in the three exposure groups,and the differences were statistically significant(benzene exposure group:χ_Hb²=334.835,χ_PLT²=123.600,P<0.05;noise exposure group:χ_Hb²=120.954,χ_PLT²=8.986,P<0.05;combined exposure group:χ_Hb²=(51.605,χ_PLT²=15.450,P<0.05).Compared with men,women had an increased risk of RBC and Hb abnormalities with OR（95%CI）of 1.343（1.214～1.485）and 3.269（2.936～3.639）,respectively.Working age,enterprise scale and economic type were influential factors for Hb abnormalities,and enterprise scale was an influential factor for RBC abnormalities（P<0.05）.In the retrospective cohort study,the mean values of WBC,RBC,Hb,PLT and Neut in benzene-exposed workers from 2016 to 2020 were within the normal reference range,and there was no fixed trend in the annual change curve of the mean values.Compared with the time of enrollment,the WBC and Neut test values of workers increased after 1 year,2 years,3 years and 4 years after enrollment,and the RBC,Hb and PLT test values of workers decreased after 1 year,2 years and 3 years after enrollment,with statistically significant differences（P<0.05）.The results of GEE analysis showed that the risk of RBC abnormality increased by 1.064 times and the risk of Hb abnormality increased by 1.058 times for every 1 year increase in the age of benzene exposed workers.The risk of Hb abnormality in women was 1.758times higher than that in men.Combined exposure of benzene with other factors was not found to increase the risk of hematocrit abnormalities in workers（P>0.05）.ConclusionAt present,the reporting of occupational hazard items and monitoring of occupational hazard factors in the workplace of benzene-related enterprises in Guangdong Province need to be strengthened,and in-depth research on monitoring of combined exposure of multiple hazard factors should be continuously carried out.The departments should increase the supervision of occupational health of key scale enterprises and help enterprises to upgrade,and improve the health examination rate of enterprises and the occupational medical examination rate of workers in employment period.The proportion of noise exposure in the working environment of benzene-related enterprises in Guangdong Province is relatively high.The combined exposure of benzene and noise has significant effects on occupational workers,and noise is also a threat to workers’blood health,so it is recommended to pay attention to the abnormal hemogram of noise-exposed workers.It is recommended to pay attention to the changes of RBC and Hb in occupational benzene exposed workers.Gender,age and enterprise characteristics are the influencing factors of abnormal peripheral blood cell count of benzene-exposed workers,and greater attention and protection should be given to key areas,key industries,and key populations in occupational worker health promotion.