McDonald J C, Sebastien P, Armstrong B
Br J Ind Med. 1986 Jul;43(7):445-9. doi: 10.1136/oem.43.7.445.
Chest radiographs taken by a standard technique were obtained from 173 current employees (164 men, 9 women) of a vermiculite mine in Montana, from 80 of 110 past employees resident within 200 miles, and from 47 men from the same area without known exposure to dust. In 43 of the 80 and 24 of the 47 an earlier chest x ray film was retrieved from the hospital archives. All 367 films were assessed blind and independently by three experienced readers using the ILO 1980 classification. Median radiographic assessment scores were analysed in relation to estimated cumulative exposure to the amphibole fibres that contaminate the vermiculite. Logistic regression analyses showed independent effects of age, smoking, and exposure on the prevalence of small opacities and of age and probably of exposure on pleural thickening. Overall, the data suggest that by retirement age the increase in prevalence of small opacities (greater than or equal to 1/0) lies between 5% and 10% per 100 f/ml years. This gradient may be somewhat steeper than for chrysotile miners and millers, but not much so.
采用标准技术对蒙大拿州一家蛭石矿的173名在职员工（164名男性，9名女性）、距离该矿200英里范围内居住的110名离职员工中的80名以及该地区47名已知无粉尘接触史的男性进行了胸部X光片拍摄。在80名离职员工中的43名以及47名无粉尘接触史男性中的24名身上，从医院档案中找回了更早的胸部X光片。所有367张X光片由三名经验丰富的阅片者采用国际劳工组织1980年分类法进行盲法独立评估。分析了与估计的被闪石纤维污染的蛭石累积接触量相关的中位放射学评估分数。逻辑回归分析显示，年龄、吸烟和接触对小阴影患病率有独立影响，年龄以及可能的接触对胸膜增厚有影响。总体而言，数据表明到退休年龄时，小阴影（大于或等于1/0）患病率每100 f/ml年的增加幅度在5%至10%之间。这一梯度可能比温石棉矿工和磨工的梯度稍陡，但差别不大。
