Matanoski G, Francis M, Correa-Villaseñor A, Elliott E, Santos-Burgoa C, Schwartz L
Department of Epidemiology, Johns Hopkins University, Baltimore, MD.
IARC Sci Publ. 1993(127):363-74.
The standardized mortality ratios for some cancers of the lymphohaematopoietic system were high in an early cohort analysis. Since the presence of large numbers of unexposed workers could conceal risks within a cohort, a case-control study was designed to examine the relationship between estimated exposures and the occurrence of these cancers. The results suggested that the risk for leukaemia was associated with exposure to butadiene and with work in specific areas. Modelling, using rank scores, indicated an increase in the risk for leukaemia with increasing exposure score. Use of cases validated by review of hospital records and selection of a new set of controls did not change the findings. The data indicated that comparison of scores within the same time frame improved the model and increased the estimated odds ratio, suggesting that exposure time or dose rate may prove to be the important variable for risk. Exact measurements from the companies involved showed significant correlations between assigned ranks and level of exposure derived from personal monitoring for butadiene but not for styrene. Thus, use of the measured values might be expected to show an association between leukaemia and exposure to butadiene. The standardized mortality ratio for leukaemia among long-term workers hired before 1960 who had worked in the three plants where the geometric mean butadiene level was three to five times higher than those in the other plants is 1.8 times higher than that of the US population. An appropriate algorithm for comparing cases and controls on the bases of the measured samples is being developed.
在早期队列分析中，某些淋巴造血系统癌症的标准化死亡率较高。由于大量未暴露工人的存在可能掩盖队列中的风险，因此设计了一项病例对照研究，以检验估计暴露与这些癌症发生之间的关系。结果表明，白血病风险与丁二烯暴露以及特定区域的工作有关。使用秩次分数进行建模表明，随着暴露分数的增加，白血病风险增加。通过审查医院记录验证病例并选择一组新的对照，并未改变研究结果。数据表明，在同一时间范围内比较分数可改善模型并提高估计的优势比，这表明暴露时间或剂量率可能是风险的重要变量。相关公司的精确测量结果显示，分配的秩次与丁二烯个人监测得出的暴露水平之间存在显著相关性，但与苯乙烯无关。因此，预计使用测量值可能会显示白血病与丁二烯暴露之间存在关联。1960年之前受雇的长期工人中，在丁二烯几何平均水平比其他工厂高三至五倍的三个工厂工作的白血病标准化死亡率比美国人群高1.8倍。正在开发一种基于测量样本比较病例和对照的适当算法。
