| Objective:We aimed to 1)explore the relationship between the occupational polycyclic aromatic hydrocarbons(PAHs)exposure and the prevalence of mild cognitive impairment(MCI),2)explore the relationship between urinary polycyclic aromatic hydrocarbon metabolites(OHPAHs)and workers' cognitive function in different field.Methods:A total of 1064 workers were recruited from a coke oven plant and a water treatment plant.Workers in the water treatment plant were controls.With workers' consent,we applied a pre-tested questionnaire to collect the workers' sociodemographic information,applied the profile of mood states(POMS)questionnaire of NCTB test to assess workers' emotional state,applied the Montreal Cognitive Assessment to assess workers' cognitive function and calculated the prevalence of MCI.We collected workers' morning urine and the concentrations of eleven PAHs metabolites were determined by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).Then,the Chi-square analysis was used to compare the MCI prevalence between coke oven workers and controls.Multiple logistic regression model was used to analyze the relationship between PAHs metabolites and prevalence of MCI in coke oven workers.The multiple linear regression model was used to analyze the relationship between PAHs metabolites and POMS,Mo CA scores.A trend test and the Restricted cubic spline(RCS)were used to analysis the dose-response relationship between PAHs metabolites and POMS,Mo CA scores.Results:1.Basic characteristics of the coke oven workers and water treatment plant workers: The average age of the workers were 46.84 ± 7.04 years,and the main members were male(90.3%).Compared with water treatment plant workers,the coke oven workers had more number of men(93.4% vs.86.1%),fewer people with monthly income above 2000 yuan(74.3% vs.84.4%),fewer people often participated in physical exercises(33.6% vs.40.5%),and more people worked night shifts(70.7% vs.63.2%).In addition,there was no statistical difference in the age,education,marital status,smoking status,drinking status,and tea drinking status(P> 0.05).Compared with water treatment plant workers,coke oven workers' emotional states scored higher on five negative emotions,while potent-active positive scores were lower,and the difference was statistically significant.Among the scores of the Mo CA scale,coke oven workers' visual space and executive function(3.69 vs.4.02,P <0.001),language(2.25 vs.2.36,P = 0.014),abstraction(1.44 vs.1.61,P <0.001),the total score(25.72 vs.26.40,P <0.001)is lower than the water treatment plant workers.2.The MCI prevalence of workers: According to two different screening standards,the MCI prevalence of workers in the two factories was calculated.The results showed that according to 26,the MCI prevalence for coke oven workers was 40.5%.The MCI prevalence for water treatment plant workers was 30.2%.According to 22,the MCI prevalence for coke oven workers was 7.7%,and the MCI prevalence for water treatment plant workers was 5.3%.Chi-square test results showed that the MCI prevalence of workers in the coking plant was higher than that in the control plant(P <0.05).3.Workers' PAHs exposure levels: The detection rates of eleven OH-PAHs metabolites of workers in both factories were above 75%.About coke oven workers,urinary 2-hydroxynaphthalene(2-OHNap)levels were the highest(0.551ng/m L).About water treatment plant workers,urinary 9-hydroxyphenanthrene(9-OHPhe)levels were the highest(0.289 ng/m L).Compared with water treatment plant workers,except for 9-OHBap,3-OHChr and 6-OHChr,the levels of coke oven workers' PAHs metabolites were higher.4.Workers urinary PAHs metabolites and cognitive function(1)The relationship between OH-PAHs and MCI prevalence in oke oven workers: The results of multiple logistic regression model analysis showed that the risk of MCI in the 2nd tertile group and the 3rd tertile group was increased by 1.78 times(OR=1.78,95%CI: 1.095-2.904)and 2.24 times(OR=2.24,95%CI: 1.086-4.609)compared with the 1st tertile group after adjusted for covariates.We found that each one-unit increase in lntransformed levels of 2-OHNap and 1-OHPyr,the risk of worker's MCI increases by 1.70 times and 1.72 times(OR=1.70,95%CI: 1.112-2.591;OR=1.72,95%CI: 1.031-2.855)when the OH-PAHs as continuous variables.The trend test showed that urinary 2-OHNap levels were associated with the increased trends for the risk of workers' MCI(P for trend = 0.044).The RCS curve showed that urinary 2-OHNap increases with the increase of the risk of workers' MCI(P =0.0156).The results showed that 2-OHNap was a risk factor for MCI in workers,and there was a dose-response relationship.(2)The relationship between urinary OH-PAHs and coke oven workers' emotional state scores: The results of linear trend test showed that 1-OHNap was negative correlated with Confusion-Bewilderment,Depression-Dejection,Tension-Anxiety scores after adjusting for covariates(All P for trend <0.05).The dose-response relationship was not observed by the RCS curve.The results of multivariate analysis showed that each one-unit increase in ln-transformed levels of 1-OHNap was associated with a 0.98 decrease in Confusion-Bewilderment scores,a 1.27 decrease in TensionAnxiety scores(P <0.05).(3)The relationship between urinary OH-PAHs and coke oven workers' Mo CA test indicators scores: The results of linear trend test showed that 2-OHNap was negative correlated with Mo CA total cores after adjusting for covariates(P for trend=0.018).The dose-response relationship of the 2-OHNap levels with decreased Mo CA total cores was confirmed in the RCS models(P = 0.0016),The results of multiple linear regression model analysis showed that each one-unit increase in ln-transformed levels of 2-OHNap was associated with a 0.67 decrease in Mo CA total cores after adjusting for covariates(P<0.05).The results showed that 2-OHNap was a risk factor for the reduction of Mo CA total cores in workers,and there was a dose-response relationship.(4)There was a negative correlation between urinary 3-OHFlu,2-OHFlu,3-OHChr and the named scores on the Mo CA scale of workers(?=-0.07,P=0.047;?=-0.08,P=0.023;?=-0.03,P=0.046),and a negative correlation between urinary 2-OHNap and attention scores on the Mo CA scale of workers(?=-0.14,P=0.040),and a negative correlation between urinary 1-OHPhe,1-OHPyr and the orientation scores on the Mo CA scale of workers(?=-0.08,P=0.019;?=-0.10,P=0.018).We did not find a dose-response relationship between them by the trend test and RCS analysis.Conclusion:1.We found a dose-response relationship between PAHs exposure and MCI prevalence rates.And needind cohort studies to demonstrate the causal relationship.2.Occupational exposure to PAHs is a risk factor for the decrease of the Mo CA total cores,and there is a negative correlation between OH-PAHs and workers' cognitive function,which is mainly manifested in visual feature analysis,instantaneous memory,visual perception,execution,and attention,calculation functions and directional forces.3.There is a negative correlation between occupational exposure to PAHs and workers' emotional states,which are mainly manifested in the aspects of ConfusionBewilderment,Depression-Dejection and Tension-Anxiety. |
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