The Effects Of Occupational Exposure To Dimethylformamide On Workers' Liver Function And Heart

Background N,N-dimethylformamide(DMF) is a universal solvent of ready miscibility with water and various organic compounts.It is commonly used in the manufactures of synthetic fiber, synthetic leather, medicine, pesticides, elctronics,polymer such as polyurethane and polyacrylonitrile and so on. DMF is rapidly absorbed by inhalation or dermal contact and its target organ of metabolism is liver. Exposure to DMF would cause damages of reproductive system, respiratory system, digestive system and nerves system. Most of clinic reports and mechanism researches on DMF are about hepatotoxicity, while researches on cardiac toxicity caused by long-term exposure to DMF are fewer.Objectives The objectives of this study were to know about workers'general situation in the polyurethane leather factory and study the correlation between workers'body health, such as liver or heart, and the concentration of DMF,working time and factors, then provide theory to clinic diagnosis and prevention.Methods One of the largest synthetic leather factories in Hefei was chosen to take on this investigation. The DMF concentrations in the air at the workplace were monitored according to national standards and the relative data were collected; face-to-face interview was given to workers across the predesigned questionnaire; physical examination was executed and then the results of workers'lever function of different exposure levers were analyzed; 79 workers were selected by stratified sampling according to their exposure concentration to DMF and myocardial enzymes tests were given to them to measurement their CKMB, LDH, AST levers, and then the correlations between myocardial enzymes and exposure concentration were come out.Results①Workplace air measurements: The monitoring data of toxic substances in the workplace air showed that concentrations of DMF at many points exceeded national standards.And of these points,concentrations of dry and wet processes were significantly higher than other processes and coating and washing were significantly higher than other points.②General situation for the study population: There was a frequent turnover of post in the high concentration group, and their awareness of protection were better than that of the other two groups.All the workers in the factory were long-sleeved clothes in winter but short- sleeved clothes in summer and autumn.Most of them used no gluves and personal protective equipments. Most workers exposed to DMF were male, and their average age and length of service are lower than the workers without exposure to DMF. Neurological symptoms and respiratory symptoms in low-concentration exposure group were significantly lower than those of the other two groups(P<0.05).There were no statistical significance in other symptoms(P>0.05)。③Laboratory testing showed that there was a statistical significance in levers of ALT and STB of male workers during these three groups, further analysis showed that the high-concentration exposure group were significantly higher than the control and the low(P<0.05). There was no significant difference in direct bilirubin(DB) and indirect bilirubin(P>0.05). The abnormality rates of ALT, STB and indirect bilirubin in the high group were higher than the control and the low. The abnormality rate of DB in the low-concentration group was higher than the high. There was a statistical correlation between ECG abnormality rates and exposure concentrations (P<0.05).Classifying these cardiogram results in to three groups, the normal, abnormal, and sinus arrhythmia , we found that there were no significant difference in age and working duration during these groups(P>0.05). The average lever of CKMB of the abnormal group was significantly higher than the other two groups(P<0.05). As to workers with a cardiogram abnormality, their risks of CKMB abnormality rose.There were no stastistical correlation between lever of CKMB, ages, working durations and exposure concentrations of DMF.Conclusions The DMF exposure was highest in the mixing the slurry, coating and washing process. And workers with these jobs were more likely to have diseases on liver or heart than the control and the low, therefore, we suggested that efforts should be concentrated on improving production process and engineering controls in reducing workplace DMF exposure. Liver function abnormality was significantly associated with elevated ALT,AST and STB changes, while, injury of heart is mainly reflected by the test of cardiogram and myocardialenzymes, however, a new research is to be carried out with more sophisticated index and to find outthe exact mechanism of these injuries.