Blot W J, Henderson B E, Boice J D
International Epidemiology Institute, Rockville, MD 20850, USA.
Nutr Cancer. 1999;34(1):111-8. doi: 10.1207/S15327914NC340115.
Over the past two decades a series of epidemiological studies have examined the relationship between consumption of cured meats during pregnancy and the subsequent risk of brain tumors, as well as other cancers, in the offspring. The research was prompted in large part by experimental investigations showing that transplacental exposure to certain N-nitroso compounds, i.e., nitrosoureas, could produce brain tumors in laboratory animals. Fourteen such epidemiological studies, 13 of which used the case-control approach, are reviewed here. Most of the studies showed no significant association between total cured meat intake and childhood cancer risk but more found positive than negative relationships. Furthermore, several studies reported significant positive associations for maternal and sometimes childhood or paternal consumption of one or more cured meats, with odds ratios of twofold or greater reported among the highest consumers. On the other hand, a correlation analysis found no positive concordance between temporal trends from the 1970s to 1990s in childhood brain cancer rates and cured meat consumption, inasmuch as cancer rates rose over time while residual nitrite levels in cured meats fell sharply. Because of the potential for bias, especially recall bias, and/or confounding, the relatively weak magnitude of the associations reported, and the inconsistency between study findings, at this time it cannot be concluded that eating cured meat has increased the risk of childhood brain cancer or any other cancers. Moreover, although N-nitroso compounds are sometimes found in cured meats or may be formed endogenously, there is no empirical evidence that eating cured meats results in human neural nitrosourea exposure. Nevertheless, the hypothesis that eating nitrite-cured meats may influence childhood and perhaps adult brain cancer cannot be dismissed. Unbiased evaluation of the hypothesis may derive from the conduct of cohort studies, where the interview-derived information on cured meat intake precedes, or is not otherwise associated with, the diagnosis of cancer.
在过去二十年里，一系列流行病学研究探讨了孕期食用腌制肉类与后代患脑肿瘤及其他癌症风险之间的关系。这项研究很大程度上是由实验研究引发的，这些实验表明经胎盘接触某些N-亚硝基化合物（即亚硝基脲）可在实验动物中诱发脑肿瘤。本文综述了十四项此类流行病学研究，其中十三项采用了病例对照研究方法。大多数研究表明，腌制肉类的总摄入量与儿童癌症风险之间无显著关联，但发现呈正相关的研究多于呈负相关的研究。此外，几项研究报告称，母亲、有时儿童或父亲食用一种或多种腌制肉类存在显著正相关，在摄入量最高的人群中，比值比高达两倍或更高。另一方面，一项相关性分析发现，20世纪70年代至90年代儿童脑癌发病率的时间趋势与腌制肉类消费之间不存在正一致性，因为随着时间推移癌症发病率上升，而腌制肉类中的残留亚硝酸盐水平却大幅下降。由于存在偏倚的可能性，尤其是回忆偏倚和/或混杂因素，报告的关联程度相对较弱，且研究结果不一致，目前尚不能得出食用腌制肉类会增加儿童脑癌或任何其他癌症风险的结论。此外，尽管在腌制肉类中有时会发现N-亚硝基化合物，或者它们可能内源性形成，但没有实证证据表明食用腌制肉类会导致人体接触神经亚硝基脲。然而，食用亚硝酸盐腌制肉类可能影响儿童甚至成人脑癌的假说不能被忽视。对该假说的无偏评估可能来自队列研究，在队列研究中，通过访谈获得的腌制肉类摄入量信息先于癌症诊断，或者与癌症诊断没有其他关联。
