Takahashi K, Case B W, Dufresne A, Fraser R, Higashi T, Siemiatycki J
Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan.
Occup Environ Med. 1994 Jul;51(7):461-9. doi: 10.1136/oem.51.7.461.
Lung asbestos burden was compared with exposure indices derived from job history interviews in 42 male subjects originating from the Montréal Case-Control Study project, 12 of whom had documented asbestos exposed job histories. Job interview data consisting of a chronological timetable of job histories were translated into detailed exposure indices by an expert group of hygienists and chemists. Total and individual asbestos fibre type concentrations were quantified by transmission electron microscopy with fibre identification by energy dispersive chi ray spectrometry after deparaffinisation of tissue blocks and low temperature plasma ashing. Geometric mean or median asbestos content was higher in subjects with an asbestos exposed job history than those without for retained dose of amosite, total commercial amphiboles, and total asbestos fibre. Except for crocidolite fibre diameter, which was significantly less in the lungs of exposed workers, no consistent differences were found in measurements of fibre dimension for any fibre type. Subgroups of subjects exposed to silica, metals, or smokers and non-smokers without significant occupational exposure showed varying patterns of lung asbestos fibre type deficit compared with the asbestos exposed subgroup. There was an overall trend for higher lung asbestos content proportional to higher exposure indices for asbestos representing concentration, frequency, and reliability. These exposure indices as well as duration of exposure (in years) were independent predictors of total asbestos content in regression analyses when combined in a model with age. Stepwise regression indicated that exposure concentration was the most important variable, explaining 32% of the total variation in total asbestos content. Smoking, whether expressed in ever or never smoked dichotomy or in smoked-years, had no relation to lung asbestos content in this model.
在来自蒙特利尔病例对照研究项目的42名男性受试者中，将肺石棉负荷与根据工作史访谈得出的暴露指数进行了比较，其中12人有记录在案的石棉暴露工作史。由卫生学家和化学家组成的专家组将包含工作史时间顺序表的工作访谈数据转化为详细的暴露指数。通过透射电子显微镜对组织块进行脱石蜡处理和低温等离子体灰化后，利用能量色散χ射线光谱法对石棉纤维进行识别，从而对石棉纤维总量和各类纤维的浓度进行定量分析。对于留存的铁石棉剂量、商业用角闪石总量和石棉纤维总量，有石棉暴露工作史的受试者的几何平均或中位数石棉含量高于无此暴露史的受试者。除了青石棉纤维直径在暴露工人的肺部明显较小外，未发现任何纤维类型在纤维尺寸测量上存在一致差异。与石棉暴露亚组相比，暴露于二氧化硅、金属的亚组或无显著职业暴露的吸烟者和非吸烟者，其肺部石棉纤维类型存在不同的缺失模式。总体趋势是，与代表浓度、频率和可靠性的石棉暴露指数越高，肺部石棉含量越高。在与年龄结合的模型中进行回归分析时，这些暴露指数以及暴露持续时间（以年计）是总石棉含量的独立预测因素。逐步回归表明，暴露浓度是最重要的变量，可以解释总石棉含量总变异的32%。在该模型中，吸烟无论是以曾经吸烟或从不吸烟的二分法表示，还是以吸烟年数表示，均与肺部石棉含量无关。
