Rodu Brad, Jansson Christer
Department of Pathology, School of Medicine, LHRB 156, University of Alabama at Birmingham, Birmingham, AL 35294-0007, USA.
Crit Rev Oral Biol Med. 2004 Sep 1;15(5):252-63. doi: 10.1177/154411130401500502.
Smokeless tobacco has been associated with oral cancer for many decades. The purpose of this article is to review research relevant to this association, including epidemiologic studies, studies of putative carcinogens such as tobacco-specific nitrosamines (TSNAs) and other contaminants, and possible cancer inhibitors. Epidemiologic studies addressing this issue primarily consist of case-control studies. They show that the use of chewing tobacco and moist snuff is associated with very low risks for cancers of the oral cavity and related structures (relative risks [RR] from 0.6 to 1.7). The use of dry snuff is associated with higher RRs, ranging from 4 to 13, while the RRs from smokeless tobacco, unspecified as to type, are intermediate (RR = 1.5 to 2.8). With regard to TSNAs, historical levels in American moist snuff products were higher than those in their Swedish counterparts, but levels in contemporary products are uniformly low. TSNA levels in chewing tobacco have always been low, but levels in dry snuff have been higher, including some very high levels in current products. In general, smokeless tobacco users are not exposed to significant levels of cadmium, lead, benzo(a)pyrene, polonium-210, and formaldehyde, when compared with concentrations of these compounds in foods. Finally, low oral cancer risk from smokeless tobacco use may be influenced by the presence of cancer inhibitors, mainly anti-oxidants, in smokeless tobacco products.
几十年来，无烟烟草一直与口腔癌有关。本文的目的是回顾与这种关联相关的研究，包括流行病学研究、对烟草特有亚硝胺（TSNAs）等假定致癌物和其他污染物的研究，以及可能的癌症抑制剂。针对这一问题的流行病学研究主要包括病例对照研究。这些研究表明，嚼烟和湿鼻烟的使用与口腔及相关结构癌症的极低风险相关（相对风险[RR]为0.6至1.7）。干鼻烟的使用与较高的相对风险相关，范围为4至13，而未指明类型的无烟烟草的相对风险则处于中间水平（RR = 1.5至2.8）。关于烟草特有亚硝胺，美国湿鼻烟产品的历史含量高于瑞典同类产品，但当代产品中的含量普遍较低。嚼烟中的烟草特有亚硝胺含量一直较低，但干鼻烟中的含量较高，包括当前产品中的一些非常高的含量。一般来说，与这些化合物在食物中的浓度相比，无烟烟草使用者接触到的镉、铅、苯并(a)芘、钋-210和甲醛的含量并不高。最后，无烟烟草产品中存在的癌症抑制剂（主要是抗氧化剂）可能会影响无烟烟草使用导致的口腔癌低风险。
