1817名铸造厂工人缺血性心脏病的队列研究

目的研究铸造作业工人缺血性心脏病发病风险及其与铸造作业、矽尘累积接触量之间的剂量-反应关系,并对缺血性心脏病的发病风险进行预测。方法采用队列研究方法,选择某铸造厂1980年1月1日-1996年12月31日在册一年以上的铸造作业工人建立研究队列,观察终止日期为2009年12月31日。以浇注、配砂、清理、熔炼、天车、造型和制芯等工种工人作为铸造组,电工、钳工和检查工等辅助工作为对照组。使用SPSS软件Cox回归模型分析缺血性心脏病发病风险及其与铸造作业、矽尘累积接触量之间的剂量-反应关系,并使用logistic回归建立缺血性心脏病发病风险的预测模型。结果本研究共随访30年,1817人,45 553.05人年,缺血性心脏病156例,人-年发病率为342.46/10万,平均发病年龄51.46岁,发病工龄21.61年。男性、吸烟、饮酒、年龄和工龄分别都是缺血性心脏病发病的危险因素。缺血性心脏病发病风险与矽尘累积接触量呈正相关,调整吸烟的影响后,工人矽尘年累积接触量每增加1mg/m3,缺血性心脏病发病风险增加75.8%(RR=1.758,95%CI1.221～2.532)。铸造组工人缺血性心脏病发病风险显著增加,调整吸烟的影响后,与对照组工人相比,配砂工、清理工、熔炼工、造型工、制芯工分别增加1.048倍、1.395倍、70.4%、97.0%和1.270倍。根据预测模型,工人缺血性心脏病发病概率随日接触矽尘浓度的增加、接尘工龄的延长而增加。结论铸造作业工人面临较大的缺血性心脏病发病风险。不同工种工人缺血性心脏病发病风险不同,其中,配砂、清理、熔炼、造型、制芯工人较高。铸造作业、矽尘累积接触量是缺血性心脏病的独立危险因素。缺血性心脏病预测模型表明,发病概率与日接触矽尘浓度和接尘工龄呈明显的剂量-反应关系。

Cohort study of ischemic heart disease among 1817 workers in a foundry

Objective To determine the risk of ischemic heart disease among foundry workers and the exposure-response relationship between the risk and foundry work and cumulative exposure to silica dust,and to establish a regression model to predict the risk for developing ischemic heart disease by a given length of employment and exposure to silica dust in foundry workers.Methods Cohort study was conducted,following-up workers in an automobile foundry employed for more than one year during January 1,1980 to December 31,1996 as cohort members.In total,30 years were followed to December 31,2009.In cohort,workers exposed to pouring,sand preparation,cast shakeout and finishing,melting,overhead crane operation,moulding and core-making were in foundry group,and auxiliary workers at the same factory,such as electricians,fitters,and inspectors were in control group.The risk of ischemic heart disease among foundry workers and the exposure-response relationship between the risk and foundry work and cumulative exposure to silica dust were analyzed with cox regression model using SPSS software,and a logistic regression model was established for prediction of risk for developing ischemic heart disease at a given length of employment and exposure to silica dust in foundry workers.Results Totally,1817 workers were followed-up for 45 553.05 person-years during 30 years,with 156 cases of ischemic heart disease and incidence of 342.46 per 100 000 person-years.And the average age at onset was 51.46 years and duration of employment at onset was 21.61 years.Results showed that male,smoking,alcohol drinking,age and duration of employment were risk factors for ischemic heart disease.Risk of ischemic heart disease in foundry workers positively correlated with cumulative silica exposure,and the risk of ischemic heart disease increased by 75.8 percent(RR=1.758,95%CI 1.221-2.532) with cumulative silica exposure of 1 mg/m3·year,adjusted for smoking.And risk of ischemic heart disease was significantly higher in the exposed group than that in the control one.Compared with control group workers,risk of ischemic heart disease increased by 1.048 folds,1.395 folds,70.4 percent,97.0 percent and 1.270 folds among workers exposed to sand preparation,cast shakeout and finishing,melting,moulding and core-making,respectively,adjusted for smoking.Based on the predictive of model,risk for developing ischemic heart disease increased with the length of employment and exposure to silica dust in foundry workers.Conclusion Workers in foundry face high risk of ischemic heart disease.Risk of ischemic heart disease varies by job,which is higher in workers exposed to sand preparation,cast shakeout and finishing,melting,moulding and core-making.Both foundry work and cumulative exposure to silica are risk factors.The model for prediction of risk for developing ischemic heart disease at a given length of employment and exposure to silica dust in foundry workers resulted in a valid exposure-response relationship.