Ritz B, Morgenstern H, Moncau J
Department of Epidemiology and Center for Occupational and Environmental Health, School of Public Health, University of California, Los Angeles 90095-1772, USA.
Epidemiology. 1999 Mar;10(2):135-40.
In a cohort of 4,563 nuclear workers followed retrospectively from 1950 to 1994, we found that age at exposure modified the effects of external radiation dose on cancer mortality. Analyses involved application of conditional logistic regression to risk sets of age- and calendar time-matched cancer deaths, with covariates treated as time dependent and with cumulative radiation doses divided according to the age intervals in which exposure occurred. After adjustment for confounding factors, we found that workers exposed to external radiation after the age of 50 years experienced exposure-related elevations in mortality from cancer at any site [rate ratio (RR) = 1.98; 95% confidence interval (CI) = 0.63-6.26], radiosensitive solid cancer (RR = 3.29; 95% CI = 1.10-9.89), and lung cancer (RR = 3.89; 95% CI = 1.23-12.3) substantially greater (1.6- to 3.5-fold greater) than were seen in coworkers exposed at all earlier ages. In contrast, all of the radiation doses contributing to mortality from cancers of the blood and lymph system were received before age 50 (for age <50, RR = 2.73 and 95% CI = 1.46-5.10; for age > or =50, RR = 0.24 and 95% CI = 0.00-687). Our results for cancer of any site are consistent with the results of previous studies examining the effects of exposure age in nuclear workers. Thus, effects of low-level radiation doses may depend on exposure age, and furthermore, patterns of effect modification by age may differ by type of cancer.
在一组从1950年到1994年进行回顾性随访的4563名核工业工人中，我们发现接触辐射时的年龄改变了外部辐射剂量对癌症死亡率的影响。分析涉及将条件逻辑回归应用于年龄和日历时间匹配的癌症死亡风险集，将协变量视为随时间变化，并根据接触发生的年龄间隔划分累积辐射剂量。在对混杂因素进行调整后，我们发现50岁以后接触外部辐射的工人，其任何部位癌症的死亡率因接触辐射而升高[率比(RR)=1.98；95%置信区间(CI)=0.63 - 6.26]，对辐射敏感的实体癌(RR = 3.29；95% CI = 1.10 - 9.89)以及肺癌(RR = 3.89；95% CI = 1.23 - 12.3)显著高于(高1.6至3.5倍)所有更早年龄接触辐射的同事。相比之下，导致血液和淋巴系统癌症死亡的所有辐射剂量都是在50岁之前接受的(对于年龄<50岁，RR = 2.73，95% CI = 1.46 - 5.10；对于年龄≥50岁，RR = 0.24，95% CI = 0.00 - 687)。我们关于任何部位癌症的研究结果与之前研究核工业工人接触辐射年龄影响的结果一致。因此，低水平辐射剂量的影响可能取决于接触辐射的年龄，此外，年龄对影响的修正模式可能因癌症类型而异。
