Dust exposure and lung cancer in Quebec chrysotile miners and millers
Dust exposure and lung cancer in Quebec chrysotile miners and millers
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DOI：
10.1016/s0003-4878(97)00053-7
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发表时间：
1998-01-01
影响因子：
--
通讯作者：
McDonald, JC
中科院分区：
文献类型：
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作者：
Liddell, FDK;McDonald, AD;McDonald, JC
自1966年以来，一直在对1891年至1920年期间出生并在魁北克温石棉生产行业至少工作了一个月的一大批男子进行研究。这些人从第一次就业（最早在1904年）到1992年被跟踪，到那时已经有8000多人死亡，657人死于肺癌。目前的研究对象是在三个地方工作的488例肺癌患者，即：特福德矿区的一个大型综合企业，这里称为3号公司（243例），阿斯彭镇的矿山和磨坊（206例），以及该镇的一个小型石棉制品厂（39例）。在每宗个案中，在工作地点、开始工作的年龄、吸烟习惯及出生日期配对后，从幸存者中随机选择四名被指涉者。这一进程非常成功，尽管有6个案件的参考资料不足4份。对于每个人（488个案例，1941个参考）在每个日历年的就业酸，我们得到了一年中的分数工作在不同的强度水平，评估在13个“灰尘类别”的mpcf（百万颗粒每立方英尺）。然后，我们计算了每个人在这些不同的水平上花费了多少年;这些西尔斯，根据工作周的长度进行调整（1937年之前为66小时; 1938-1949年为48小时; 1950-1985年为40小时），在病例死亡之前累积了10年。这些人被分为不吸烟者、戒烟者和吸烟者。对于3号公司的每个人和每个人的一个参照物，他在五个矿井的中心区域和十个矿井的外围区域工作的年份是不同的;已知纤维透闪石对温石棉的污染在中心区域比在外围区域大得多。在就业场所内，情况下，参照比较，条件Logistic回归。正如先前的受试者-年分析所预测的那样，无论在何处，在粉尘类别1和2（平均值为0.5和2百万立方英尺）中工作的年份，肺癌风险可忽略不计;由于类别1的上限大大高于目前允许的上限，因此，在允许的水平上接触温石棉的肺癌风险可被视为极小。较高类别的确认反应模式是不规则的。在3号公司，一些风险似乎随着在较高粉尘类别中度过的年份而升高：3-4，5-7，8-10和11-13，平均值分别约为9，20，36和92 mpcf。对于类别3-4：索引8-10，优势比是高的一些或所有的工作在中心区，但最小的西尔斯花在周边地区。在5-7类工作的吸烟者以及在最高类别（11-13）工作的吸烟者的比值比相当低。在阿斯彭的矿山和磨坊，除了7-13类（约100年）的非吸烟者和戒烟者工作的年份外，所有风险都很低。40百万立方英尺）。工厂的风险没有增加。从主体-年分析中得知，大部分过量发生在3号公司，但现在清楚的是，从所有实际目的来看，它仅限于那里的中心区域，可能主要是由于纤维透闪石和至少3类粉尘的粉尘条件。这一类别的平均值为7 mpcf或非常粗略的24纤维/ml，比今天的卫生标准高出两个数量级。(C)1998年英国职业卫生学会。出版社：Elsevier Science Ltd
A large cohort of men born between 1891 and 1920 and employed for at least a month in the chrysotile producing industry of Quebec has been under study since 1966. These men were followed from first employment (the earliest in 1904) to 1992, by which time over 8000 had died, 657 from lung cancer. The current study is of 488 cases of lung cancer formerly employed at three places, viz. a major complex, here called Company 3, in the region of Thetford Mines (243 cases), the mine and mill in the town of Asbestos (206) and a small asbestos-products factory in the same town (39). For each case, four referents were sought by random selection from among survivors to a greater age, after matching on place of employment, age of starting work, smoking habit and date of birth. This process was highly successful, although six cases had less than four referents. For each man (the 488 cases with 1941 referents) acid for each calendar year of employment, we obtained the fraction of the year worked at various levels of intensity, assessed in 13 'dust categories' of mpcf (million particles per cubic foot). We then calculated how many years each man spent at these various levels; these Sears, adjusted for the length of the working week (66 h until 1937; 48 h 1938-1949; and 40 h 1950-1985), were accumulated up to ten years before the death of the case. The men were classified according as they vr ere non-or ex-smokers, or smokers, of cigarettes. For each man at Company 3 and one referent for each, his years of work in a central area of five mines and in a peripheral area of ten mines were differentiated; contamination of the chrysotile by fibrous tremolite was known to be much greater in the central than in the peripheral area. Case-referent comparisons, within place of employment, were made by conditional logistic regression. As anticipated from earlier subject-years analyses, lung cancer risks were found to be negligible for years worked in dust categories 1 and 2 (averaging 0.5 and 2 mpcf), regardless of place; as the upper limit of category 1 is considerably higher than permitted nowadays, the lung cancer risk from exposure to chrysotile at permitted levels can be taken as extremely small. Patterns of exposure-response for higher categories were irregular. At Company 3, some risks appeared elevated for years spent in the higher dust categories: 3-4, 5-7, 8-10 and 11-13, with averages around 9, 20, 36 and 92 mpcf, respectively. For categories 3-4 :Ind 8-10, the odds ratios were high for some or all work in the central area, but minimal for Sears spent in the peripheral area only. Odds ratios were fairly low for cigarette smokers who worked in categories 5-7 and also for years spent in the highest categories (11-13). At the mine and mill in Asbestos, all risks were low except for years worked by non-and ex-smokers in categories 7-13 (ca. 40 mpcf). There were no increased risks at the factory. It was known from the subject-years analyses that most of the excess had occurred at Company 3, but it is now clear that for all practical purposes it was confined to the central area there, probably due largely to fibrous tremolite and in dust conditions of at least dust category 3. The average of this category was 7 mpcf or very roughly 24 fibres/ml, about two orders of magnitude higher than today's hygiene standards. (C) 1998 British Occupational Hygiene Society. Published by Elsevier Science Ltd.