Carta P, Cocco P, Picchiri G
Institute of Occupational Medicine, University of Cagliari, Italy.
Am J Ind Med. 1994 Apr;25(4):489-506. doi: 10.1002/ajim.4700250404.
Starting from a cross-sectional survey in 1973, the mortality of two cohorts of Sardinian metal miners was followed through December 31, 1988. In mine A, the quartz concentration in respirable dust ranged between 0.2% and 2.0% and the exposure to radon daughters averaged 0.13 working level (WL), with the highest estimated cumulative exposure around 80-120 WLM. In mine B, the silica content was much higher (6.5-29%), but exposure to radon daughters was significantly lower than in mine A. More than 98% of the overall work force in 1973 (1,741 miners) entered the cohort, providing 25,842.5 person-years. Smoking, occupational history, chest radiographs, and lung function tests were available for the cohort members at admission. Mortality for all causes was slightly lower than expected. A significant excess for nonmalignant chronic respiratory diseases was noticed in both mines. Twenty-four subjects died of lung cancer, 17 from mine A (SMR: 128; 95% confidence interval [CI]: 75-205) and 7 from mine B (SMR: 85; 95% CI: 34-175). The SMR for lung cancer was highest among the underground workers from mine A (SMR: 148; 95% CI: 74-265), with a significant upward trend by duration of employment in underground jobs. Mine B underground miners showed lung cancer SMRs close to 100 without a significant trend by duration of employment. Among underground miners with spirometric airways obstruction in 1973, those from mine A showed the highest risk (SMR: 316; 95% CI: 116-687). The relationship did not change after adjusting for age and smoking. Based on the present findings, crystalline silica per se does not appear to affect lung cancer mortality. A slight association between lung cancer mortality and exposure to radon daughters, though within relatively low levels, may be considered for underground miners from mine A. Impaired pulmonary function may be an independent predictor of lung cancer and an important risk factor enhancing the residence time of inhaled carcinogens, i.e., alpha particles or PAHs, by impairing their bronchial and alveolar clearance.
从1973年的一项横断面调查开始，对撒丁岛两个金属矿工队列的死亡率进行跟踪，直至1988年12月31日。在矿井A中，可吸入粉尘中的石英浓度在0.2%至2.0%之间，氡子体暴露平均为0.13工作水平（WL），估计最高累积暴露量约为80 - 120工作水平月（WLM）。在矿井B中，二氧化硅含量高得多（6.5 - 29%），但氡子体暴露明显低于矿井A。1973年超过98%的全体劳动力（1741名矿工）进入该队列，提供了25842.5人年的数据。队列成员入院时可获取吸烟情况、职业史、胸部X光片和肺功能测试结果。所有原因导致的死亡率略低于预期。在两个矿井中均发现非恶性慢性呼吸道疾病显著超标。24名受试者死于肺癌，其中17名来自矿井A（标准化死亡比：128；95%置信区间[CI]：75 - 205），7名来自矿井B（标准化死亡比：85；95% CI：34 - 175）。矿井A的地下工人肺癌标准化死亡比最高（标准化死亡比：148；95% CI：74 - 265），且随着地下工作年限的增加呈显著上升趋势。矿井B的地下矿工肺癌标准化死亡比接近100，且未随工作年限呈现显著趋势。在1973年肺功能测定存在气道阻塞的地下矿工中，矿井A的矿工风险最高（标准化死亡比：316；95% CI：116 - 687）。在对年龄和吸烟情况进行调整后，这种关系并未改变。基于目前的研究结果，结晶二氧化硅本身似乎并不影响肺癌死亡率。对于矿井A的地下矿工，肺癌死亡率与氡子体暴露之间可能存在轻微关联，尽管暴露水平相对较低。肺功能受损可能是肺癌的一个独立预测因素，并且是一个重要的风险因素，通过损害支气管和肺泡对吸入致癌物（即α粒子或多环芳烃）的清除作用，延长了它们在体内的停留时间。
