McDonald J C, Harris J, Armstrong B
Imperial College School of Medicine, London, UK.
Occup Environ Med. 2004 Apr;61(4):363-6. doi: 10.1136/oem.2003.008649.
Fibrous tremolite is a widespread amphibole asbestiform mineral, airborne fibres of which constitute an environmental hazard in Libby, Montana, northern California, and elsewhere.
To determine excess risk from lung cancer, mesothelioma, and all-cause mortality in a cohort of men exposed to tremolite, but no other form of asbestos.
Mortality by certified cause and various measures of exposure to tremolite and related amphibole fibres was assessed in a cohort of 406 vermiculite mineworkers in Libby, Montana, employed before 1963 and followed until 1999.
Total deaths were: lung cancer 44 (SMR 2.40), non-malignant respiratory disease (NMRD) 51 (SMR 3.09), all causes 285 (SMR 1.27); included among the total were 12 deaths ascribed to mesothelioma (4.21% of all deaths). Adjusted linear increments in relative risks (per 100 f/ml.y), estimated by Poisson regression, were: lung cancer (0.36, 95% CI 0.03 to 1.20), NMRD (0.38, 95% CI 0.12 to 0.96), and all deaths (0.14, 95% CI 0.05 to 0.26).
The all-cause linear model would imply a 14% increase in mortality for mine workers exposed occupationally to 100 f/ml.y or about 3.2% for a general population exposed for 50 years to an ambient concentration of 0.1 f/ml. Amphibole fibres, tremolite in particular, are likely to be disproportionately responsible for cancer mortality in persons exposed to commercial chrysotile, but to what extent cannot be readily assessed.
纤维状透闪石是一种广泛分布的闪石类石棉状矿物，其空气中的纤维在蒙大拿州利比、北加利福尼亚及其他地区构成环境危害。
确定一组仅接触透闪石而无其他形式石棉的男性人群中肺癌、间皮瘤及全因死亡率的超额风险。
对蒙大拿州利比的406名蛭石矿工人进行队列研究，评估其按死因认证的死亡率以及接触透闪石和相关闪石纤维的各种指标，这些工人于1963年前受雇，随访至1999年。
总死亡人数为：肺癌44例（标准化死亡比2.40），非恶性呼吸道疾病（NMRD）51例（标准化死亡比3.09），全因死亡285例（标准化死亡比1.27）；其中间皮瘤死亡12例（占总死亡人数的4.21%）。通过泊松回归估计，相对风险的调整线性增量（每100 f/ml·年）为：肺癌（0.36，95%可信区间0.03至1.20），NMRD（0.38，95%可信区间0.12至0.96），全因死亡（0.14，95%可信区间0.05至0.26）。
全因线性模型表明，职业接触100 f/ml·年的矿工死亡率增加14%，或一般人群在50年中接触环境浓度0.1 f/ml时死亡率增加约3.2%。闪石纤维，尤其是透闪石，可能在接触商业温石棉的人群中对癌症死亡率负有不成比例的责任，但具体程度难以轻易评估。
