Liu Yuewei, Zhou Yun, Hnizdo Eva, Shi Tingming, Steenland Kyle, He Xinjian, Chen Weihong
Am J Epidemiol. 2017 Aug 15;186(4):481-490. doi: 10.1093/aje/kwx124.
The association between low-level crystalline silica (silica) exposure and mortality risk is not well understood. We investigated a cohort of 44,807 Chinese workers who had worked in metal mines or pottery factories for at least 1 year from January 1, 1960, to December 31, 1974, and were followed through 2003. Low-level silica exposure was defined as having a lifetime highest annual mean silica exposure at or under a permissible exposure limit (PEL). We considered 3 widely used PELs, including 0.05 mg/m3, 0.10 mg/m3, and 0.35 mg/m3. Cumulative silica exposure was estimated by linking a job exposure matrix with each participant's work history. For the 0.10-mg/m3 exposure level, Cox proportional hazards models showed significantly increased risk of mortality from all diseases (for each 1-ln mg/m3-years increase in logged cumulative silica exposure, hazard ratio (HR) = 1.05, 95% confidence interval (CI): 1.03, 1.07), malignant neoplasms (HR = 1.06, 95% CI: 1.03, 1.09), lung cancer (HR = 1.08, 95% CI: 1.02, 1.14), ischemic heart disease (HR = 1.09, 95% CI: 1.02, 1.16), pulmonary heart disease (HR = 1.08, 95% CI: 1.00, 1.16), and respiratory disease (HR = 1.20, 95% CI: 1.14, 1.26). The 0.05-mg/m3 and 0.35-mg/m3 exposure levels yielded similar associations. Long-term exposure to low levels (PELs ≤0.05 mg/m3, ≤0.10 mg/m3, or ≤0.35 mg/m3) of silica is associated with increased total and certain cause-specific mortality risk. Control of ambient silica levels and use of personal protective equipment should be emphasized in practice.
低水平结晶硅石（二氧化硅）暴露与死亡风险之间的关联尚未得到充分理解。我们调查了一组44807名中国工人，他们在1960年1月1日至1974年12月31日期间在金属矿或陶瓷厂工作至少1年，并随访至2003年。低水平二氧化硅暴露定义为终身最高年平均二氧化硅暴露量处于或低于允许暴露限值（PEL）。我们考虑了3种广泛使用的PEL，包括0.05 mg/m³、0.10 mg/m³和0.35 mg/m³。通过将工作暴露矩阵与每位参与者的工作经历相联系来估计累积二氧化硅暴露量。对于0.10 mg/m³的暴露水平，Cox比例风险模型显示，所有疾病导致的死亡风险显著增加（每增加1 ln mg/m³-年的对数累积二氧化硅暴露量，风险比（HR）=1.05，95%置信区间（CI）：1.03，1.07），恶性肿瘤（HR = 1.06，95% CI：1.03，1.09），肺癌（HR = 1.08，95% CI：1.02，1.14），缺血性心脏病（HR = 1.09，95% CI：1.02，1.16），肺心病（HR = 1.08，95% CI：1.00，1.16）和呼吸系统疾病（HR = 1.20，95% CI：1.14，1.26）。0.05 mg/m³和0.35 mg/m³的暴露水平产生了类似的关联。长期暴露于低水平（PEL≤0.05 mg/m³、≤0.10 mg/m³或≤0.35 mg/m³）的二氧化硅与总死亡率和某些特定病因死亡率风险增加相关。在实践中应强调控制环境二氧化硅水平并使用个人防护设备。
