Zapponi Giovanni A, Marcello Ida
Department of Technology and Health, Istituto Superiore di Sanità, 00161, Rome, Italy.
Ann N Y Acad Sci. 2006 Sep;1076:839-57. doi: 10.1196/annals.1371.076.
The hormesis theory proposes the low-dose beneficial and high-dose detrimental pattern, existing for specific conditions, as a "general default assumption" for toxicology and carcinogenicity. Crump and Kitchin and Drane underline that in a post hoc retrospective scientific literature searching for hormetic dose-response patterns, the consideration of the whole available relevant studies is necessary and, for statistical testing purposes, for instance at a 0.05 standard level, a P value obtained from 1 - (1 - P)(n) = 0.05 (i.e., P = 0.0005 for 100 examined cases) should be used (otherwise, by definition, 5 "positive" results are expected by chance over 100 cases). The hypothesis, based on some experimental data on rodents, by Calabrese and Baldwin, of an hormetic effect of 2,3,7,8-TCDD at the 1-10 ng/kgbw/day dose, of Na-saccharine in the < or = 1% of diet exposure range, of Cadmium Chloride in the 0-5 micromol/kg dose range, single injection, and of neutrons in the 0- to 2-rad dose range, are not confirmed, and, rather, are contradicted, when the whole relevant data presented by international and national agencies are considered. As far as the radiation risk is in particular concerned, a recently published epidemiological study on more than 400,000 nuclear plant workers, co-ordinated by the IARC has indicated a small, but significant risk, at the current exposure limits, and possibly below them. Therefore, the hormesis theory-based criticism of current radiation protection criteria, assumed to be excessively conservative, is not justified. Also not justified is the assumption that "by dismissing hormesis, regulatory agencies such as U.S. EPA deny the public the opportunity for optimal health and avoidance of diseases;" rather, the contrary is here considered true. Analogical considerations are not necessarily logical ones and the single result should be considered in its whole context.
兴奋效应理论提出了低剂量有益而高剂量有害的模式，该模式存在于特定条件下，是毒理学和致癌性的“一般默认假设”。克伦普、基钦和德雷恩强调，在事后回顾性科学文献中寻找兴奋效应剂量反应模式时，有必要考虑所有可得的相关研究，并且，出于统计检验目的，例如在0.05的标准水平下，应使用从1 - (1 - P)(n) = 0.05得出的P值（即对于100个检验案例，P = 0.0005）（否则，根据定义，在100个案例中预计会有5个“阳性”结果是偶然出现的）。基于对啮齿动物的一些实验数据，卡拉布雷斯和鲍德温提出的关于2,3,7,8 - 四氯二苯并二恶英在1 - 10纳克/千克体重/天剂量、糖精钠在饮食暴露范围≤1%、氯化镉在0 - 5微摩尔/千克剂量范围（单次注射）以及中子在0 - 2拉德剂量范围内存在兴奋效应的假设，在考虑国际和国家机构提供的所有相关数据时并未得到证实，反而被反驳。就辐射风险而言，国际癌症研究机构协调的一项最近发表的针对40多万核电站工人的流行病学研究表明，在当前暴露限值及可能低于该限值的情况下，存在虽小但显著的风险。因此，基于兴奋效应理论对当前被认为过于保守的辐射防护标准的批评是不合理的。同样不合理的假设是“通过摒弃兴奋效应，像美国环境保护局这样的监管机构剥夺了公众获得最佳健康和预防疾病的机会”；相反，这里认为事实恰恰相反。类比的考量不一定是合乎逻辑的，单个结果应在其整体背景下进行考虑。
