Cross-sectional Study On Adverse Effects Among Foundry Workers

ObjectiveThe purpose of the study was to describe the distribution features of health status of foundry workers and to evaluate the correlation between hypertension, liver function damage, respiratory ventilation function damage and the DNA damage of peripheral blood lymphocytes and working years, jobs and individual cumulative exposure to silica dust among foundry workers.MethodsA large-scale foundry factory in Shiyan city, Hubei province was chosen as study site, and the foundry workers who had worked for more than1year and took part in the occupational physical examination during April16th～27th2012were investigated by a cross-sectional survey. Data of work environmental monitoring for varied occupational hazards that workers had been exposed to in the foundry during the past34years was collected; levels of cumulative dust exposure for foundry workers were estimated. Data of the basic condition, working history, history of past illness, family history, and the results of physical examination of the foundry workers were collected by a questionnaire. Blood samples of the foundry workers were collected and comet assay was carried out. The distribution features of health status of foundry workers with different working years, jobs and individual cumulative exposure to silica dust were discribed. Hypertension, liver function damage, respiratory ventilation function and the DNA damage of peripheral blood lymphocytes of foundry workers with different working years, jobs and individual cumulative exposure to silica dust were analyzed with Logistic regression model and REG regression model by SAS software.Results1. Health status of and occupational health services for foundry workersIn this study, pneumoconiosis cases were not found. The largest proportion of the history of past illness was the digestive system diseases, accounting for25.64%. The largest proportion of the family history of diseases was circulatory system diseases, accounting for63.36%. The main reason of injuries was object attack, accounting for36.11%. The occupational disease prevention and occupational health services of the foundry surveyed were relatively good, however, the labour union played an insufficient role in the occupational safety and health service. The foundry workers surveyed had a stronge sense of self-protection against occupational hazards, and they obtained the knowledge of occupational health mainly from bulletins, trainings and booklets, accounting for74.49%,71.72%and63.77%, respectively. The abnormal rates of ECG, blood pressure, blood glucose, blood lipids, audiometry, liver function, and respiratory ventilation function among foundry workers were32.90%,26.06%,19.41%,16.08%,28.47%,10.91%and48.98%, respectively.2. Status of hypertension among foundry workersIn this study, the blood pressure measurement was carried out on517foundry workers, and122of them were patients with hypertension, accounting for22.55%. The risk of hypertension in smokers was2.806fold (OR=2.806,95%CI1.845～4.269) as non-smokers, the risk of hypertension rised by0.7%(OR=1.007,95%CI1.003～1.011) with an increase in cumulative silica dust exposure of1mg/m3·year.Adjusted for smoking and jobs, the risk of hypertension in male workers was3.438fold (OR=3.438,95%CI1.597～7.403) as females, in foundry workers drinking alcohol was1.744fold (OR=1.744,95%CI1.051～2.896) as those never drinking, and in those with family history of hypertension was3.166fold (OR=3.166,95%CI1.986～5.047) as those without that. The risk of hypertension rised by0.8%(OR=1.008,95%CI1.003～1.011) with an increase in cumulative silica dust exposure of1mg/m3·year.3. Status of liver function damage among foundry workersThe liver function assays was carried out on537foundry workers, and59of them were those with liver function damage, accounting for10.99%. Binary Logistic regression showed that the risk of liver function damage rised by0.4%(OR=1.004,95%CI1.000～1.008) with an increase in cumulative silica dust exposure of1mg/m3·year. Adjusted for drinking and gender, the risk of liver function damage rised by0.3%(OR=1.003,95%CI0.999-1.006) with an increase in cumulative silica dust exposure of1mg/m3·year, and the difference was statistically significant.4. Status of respiratory ventilation function damage among foundry workersIn this study, the respiratory ventilation function test was carried out on403foundry workers.94of them were those with abnormal VC,107with abnormal FVC,66with abnormal FEV1,0with abnormal FEV1/FVC,96with abnormal MMEF,173with abnormal V50and185with abnormal V25.The abnormal rates of VC, FVC, FEV1, FEV1/FVC, MMEF, V50and V25among foundry workers were23.33%,26.55%,16.38%,0.00%,23.82%,42.93%and45.91%, respectively. Adjusted for gender and jobs, there was a decrease by0.04%in VC and by0.03%in FVC with an increase in cumulative silica dust exposure of1mg/m3·year respectively. Adjusted for gender and past history of respiratory system diseases, there was a decrease by0.02%in FEV1/FVC with an increase in cumulative silica dust exposure of1mg/m3-year.In this study,107of403foundry workers were patients with restrictive ventilatory functional disturbance, none of403foundry workers was patients with obstructive ventilatory functional disturbance or mixed ventilatory functional disturbance. Binary Logistic regression showed that the risk of restrictive ventilatory functional disturbance was increased by0.9%(OR=1.009,95%CI1.004-1.014) with an increase in cumulative silica dust exposure of lmg/m3·year, the risk of restrictive ventilatory functional disturbance in the sand preparation workers was4.235fold (OR=4.235,95%CI.609～11.147) as other workers. Adjusted for jobs, the risk of restrictive ventilatory functional disturbance was increased by1%(OR=1.010,95%CI1.004～1.016) with an increase in cumulative silica dust exposure of1mg/m3·year.5. Status of DNA damage of foundry workersThe comet assay involved55workers who were divided into2groups. The first group consisted of28foundry workers, accounting for50.91%. The second group, comprising27other workers was the control group, accounting for49.09%. the olive tail moment of foundry workers was0.68±0.10μm, longer than that of other workers(0.60±0.1μm), and the difference was statistically significant.There was a positive correlation between the cumulative silica dust exposure and olive tail moment (r=0.31526, P=0.0191), and the DNA damage of peripheral blood lymphocytes of the foundry workers increased with the cumulative silica dust exposure. Adjusted for smoking, the olive tail moment of foundry workers was0.09μlonger than that of other workers, and the difference was statistically significant. Adjusted for jobs, the olive tail moment of smokers was0.07μm longer than that of the non-smokers, and the difference was statistically significant.Conclusions1. In the case of improvement of working condition, the incidence of traditional occupation diseases such as pneumoconiosis is relatively low. The occupational disease prevention and occupational health services of the enterprises surveyed are relatively good.2. There are varied adverse effects among foundry workers, including the abnormality of blood pressure, liver function, and respiratory ventilation function. The cumulative silica dust exposure is the risk factor of respiratory ventilation function damage. Attentions should be paid to work-related adverse effects among foundry workers.3. The abnormality of respiratory ventilation function is more sensitive to the injury of respiratory system of foundry workers than that of X-ray chest film.4. Foundry makes the DNA damage more serious in peripheral blood lymphocytes of foundry workers, it may be related to the carcinogenicity of foundry environment.