PLoS Med：陈卫红小组研究证实长期接触矽尘导致工人死亡率升高

华中科技大学公共卫生学院陈卫红团队的一项最新研究表明，长期接触矽尘可导致工人死亡率升高。相关成果发表在4月份的《公共科学图书馆—医学》上。

矽尘（游离二氧化硅粉尘）是地壳的主要成分，沙粒和岩石均含有较高浓度的矽尘。生产过程中产生的矽尘是我国最严重的职业性有害因素，我国接尘工人超过2000万人，美国及欧洲接尘工人分别超过170万人和300万人。

为全面评价矽尘对工人健康的损害，陈卫红领导的研究组对我国29个企业的74040名工人进行了长达44年（平均33年）的动态观察。

研究人员通过对420万个工作点的粉尘浓度测定和工人矽尘累积接触量的计算，发现接尘工人的死亡率要比非接尘工人高近两倍。进一步的研究表明，矽尘接触与工人死亡率以及呼吸系统疾病、肺结核和心血管疾病的死亡危险有显著的“剂量—反应”关系。

据陈卫红介绍，此项始于1986年的队列研究，由于涉及工人多，数据收集工作量巨大，质量控制难度高而成为该领域世界上最大的可靠队列。研究显示，低水平的矽尘接触对健康仍存在着威胁，若长期接触不超过0.1毫克/立方米的呼吸性矽尘，工人全死因、冠心病和尘肺的死亡水平将分别为全国平均死亡水平的1.06、1.65和11.01倍。

陈卫红认为，该研究提示，降低生产场所矽尘水平、减少接尘时间和加强接触工人的个体防护，能降低工人死亡率，对提高中国和其他国家矽尘接触工人的职业健康有着重要的公共卫生意义。

doi:10.1371/journal.pmed.1001206
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Long-Term Exposure to Silica Dust and Risk of Total and Cause-Specific Mortality in Chinese Workers: A Cohort Study

Weihong Chen, Yuewei Liu, Haijiao Wang, Eva Hnizdo, Yi Sun, Liangping Su, Xiaokang Zhang, Shaofan Weng, Frank Bochmann, Frank J. Hear, Jingqiong Chen, Tangchun Wu

Background Human exposure to silica dust is very common in both working and living environments. However, the potential long-term health effects have not been well established across different exposure situations. Methods and Findings We studied 74,040 workers who worked at 29 metal mines and pottery factories in China for 1 y or more between January 1, 1960, and December 31, 1974, with follow-up until December 31, 2003 (median follow-up of 33 y). We estimated the cumulative silica dust exposure (CDE) for each worker by linking work history to a job–exposure matrix. We calculated standardized mortality ratios for underlying causes of death based on Chinese national mortality rates. Hazard ratios (HRs) for selected causes of death associated with CDE were estimated using the Cox proportional hazards model. The population attributable risks were estimated based on the prevalence of workers with silica dust exposure and HRs. The number of deaths attributable to silica dust exposure among Chinese workers was then calculated using the population attributable risk and the national mortality rate. We observed 19,516 deaths during 2,306,428 person-years of follow-up. Mortality from all causes was higher among workers exposed to silica dust than among non-exposed workers (993 versus 551 per 100,000 person-years). We observed significant positive exposure–response relationships between CDE (measured in milligrams/cubic meter–years, i.e., the sum of silica dust concentrations multiplied by the years of silica exposure) and mortality from all causes (HR 1.026, 95% confidence interval 1.023–1.029), respiratory diseases (1.069, 1.064–1.074), respiratory tuberculosis (1.065, 1.059–1.071), and cardiovascular disease (1.031, 1.025–1.036). Significantly elevated standardized mortality ratios were observed for all causes (1.06, 95% confidence interval 1.01–1.11), ischemic heart disease (1.65, 1.35–1.99), and pneumoconiosis (11.01, 7.67–14.95) among workers exposed to respirable silica concentrations equal to or lower than 0.1 mg/m3. After adjustment for potential confounders, including smoking, silica dust exposure accounted for 15.2% of all deaths in this study. We estimated that 4.2% of deaths (231,104 cases) among Chinese workers were attributable to silica dust exposure. The limitations of this study included a lack of data on dietary patterns and leisure time physical activity, possible underestimation of silica dust exposure for individuals who worked at the mines/factories before 1950, and a small number of deaths (4.3%) where the cause of death was based on oral reports from relatives. Conclusions Long-term silica dust exposure was associated with substantially increased mortality among Chinese workers. The increased risk was observed not only for deaths due to respiratory diseases and lung cancer, but also for deaths due to cardiovascular disease.