Prentice R L, Yoshimoto Y, Mason M W
J Natl Cancer Inst. 1983 Apr;70(4):611-22.
Cancer mortality among 40,498 Hiroshima and Nagasaki residents was examined in relation to cigarette smoking habits and estimated atomic bomb radiation exposure level. Relative risk (RR) models that are either multiplicative or additive in the two exposures were emphasized. Most analyses were directed toward all nonhematologic (ANH) cancer, stomach cancer, lung cancer, or digestive tract cancer other than stomach cancer, for which there were, respectively, 1,725, 658, 281, and 338 deaths in the follow-up period for this study. Persons heavily exposed to both cigarette smoke and radiation were found to have significantly lower cancer mortality than multiplicative RR models would suggest for ANH cancer, stomach cancer, and digestive tract cancer other than stomach cancer. Surprisingly, the RR function appeared not only to be submultiplicative for some of these cancer site categories but also may be subadditive. The lung cancer RR function could not be distinguished from either a multiplicative or an additive form. The number of deaths was sufficient to permit some more detailed study of ANH cancer mortality: RR functions appeared to be consistent between males and females, though a paucity of heavy smoking females limits the precision of this comparison. The submultiplicative nature of the RR function mentioned above was particularly pronounced among persons who were relatively young (less than or equal to 30 yr of age) at the time of radiation exposure. The RR function for these younger subjects depends strongly on both radiation and cigarette smoke exposure levels. Even light smoking (approximately 5 cigarettes/day) for an extended period of time was associated with a large estimated RR. Implications of these findings are discussed in relation to human carcinogenesis models. As a byproduct, cancer mortality of several sites is significantly related to radiation exposure in this population, after accommodation for the possible confounding effects of cigarette smoking.
对40498名广岛和长崎居民的癌症死亡率进行了调查，调查内容涉及吸烟习惯和估计的原子弹辐射暴露水平。重点研究了两种暴露因素呈乘法或加法关系的相对风险（RR）模型。大多数分析针对的是所有非血液系统（ANH）癌症、胃癌、肺癌或除胃癌外的消化道癌症，在本研究的随访期内，这些癌症分别有1725例、658例、281例和338例死亡。研究发现，同时大量接触香烟烟雾和辐射的人群，其癌症死亡率显著低于乘法RR模型对ANH癌症、胃癌和除胃癌外的消化道癌症所预测的死亡率。令人惊讶的是，RR函数不仅在某些癌症部位类别中表现为次乘法，还可能是次加法。肺癌的RR函数无法区分是乘法形式还是加法形式。死亡人数足以对ANH癌症死亡率进行更详细的研究：RR函数在男性和女性之间似乎是一致的，不过重度吸烟女性数量较少，限制了这种比较的精确性。上述RR函数的次乘法性质在辐射暴露时相对年轻（小于或等于30岁）的人群中尤为明显。这些较年轻受试者的RR函数强烈依赖于辐射和香烟烟雾暴露水平。即使长时间轻度吸烟（约每天5支）也与较大的估计RR相关。结合人类致癌模型对这些发现的意义进行了讨论。作为一个附带结果，在考虑了吸烟可能的混杂效应后，该人群中多个部位的癌症死亡率与辐射暴露显著相关。
