Howe G R, Stager R H
Division of Epidemiology, School of Public Health, Columbia University, New York, New York 10032, USA.
Radiat Res. 1996 Jul;146(1):37-42.
Exposures to radon decay products have been re-estimated for 65 men who died of lung cancer between 1950 and 1980, and 126 matched controls selected from the Beaverlodge cohort of 8,487 workers at the Beaverlodge mine in Northern Saskatchewan. The revised exposure estimates were based on a more thorough review of individual employment records for the study subjects than originally conducted, together with historic data from area-specific measurements of exposure rates in the mine. The revised cumulative exposures are approximately 60% higher than the original exposure estimates, which were based on mine-wide averages for those exposures incurred prior to 1967, and which used geometric rather than arithmetic means for area exposure rates. Despite the increase in estimated exposures using the revised estimates, the excess relative risk per 100 working level months has increased from 2.70 to 3.25, most likely due to a substantial reduction in random exposure measurement error. The new data show similar modifying effects of risk by time since exposure and age at risk as other studies of underground miners, but provide no evidence of an inverse exposure-rate effect, in contrast to a strong effect seen in the analyses based on the original exposure estimates.
对1950年至1980年间死于肺癌的65名男性以及从萨斯喀彻温省北部比弗洛奇矿8487名工人组成的比弗洛奇队列中挑选出的126名匹配对照，重新估算了他们接触氡衰变产物的情况。修订后的暴露估计值基于对研究对象个人就业记录的更全面审查，审查比最初进行的更为彻底，同时结合了该矿区特定区域暴露率的历史测量数据。修订后的累积暴露量比最初的暴露估计值高出约60%，最初的估计值基于1967年之前那些暴露的全矿平均值，且使用几何均值而非算术均值来计算区域暴露率。尽管使用修订后的估计值使估计暴露量有所增加，但每100工作水平月的超额相对风险从2.70增加到了3.25，这很可能是由于随机暴露测量误差大幅减少所致。新数据显示，与其他地下矿工研究一样，自接触以来的时间和暴露时的年龄对风险有类似的修正作用，但与基于最初暴露估计值的分析中所见的强烈效应相反，没有证据表明存在暴露率的反向效应。
