Mitacek E J, Brunnemann K D, Suttajit M, Martin N, Limsila T, Ohshima H, Caplan L S
Department of Preventive Medicine, State University of New York at Stony Brook, School of Medicine, 11794-8036, USA.
Food Chem Toxicol. 1999 Apr;37(4):297-305. doi: 10.1016/s0278-6915(99)00017-4.
The recent case-control studies in Thailand indicate that a high incidence of liver cancer in Thailand has not been associated with common risk factors such as hepatitis B infection, aflatoxin intake and alcohol consumption. While the infestation by the liver fluke Opisthorchis viverrini (OV) accounted for the high risk in north-east Thailand, there was no such exposure in the other regions of the country where the incidence of liver cancer is also high. Case-control studies suggest that exposure to exogenous and possibly endogenous nitrosamines in food or tobacco in betel nut and cigarettes may play a role in the development of hepatocellular carcinoma (HCC), while OV infestation and chemical interaction of nitrosamines may also be aetiological factors in the development of cholangiocarcinoma (CCA). Over 1800 samples of fresh and preserved food were systematically collected and tested between 1988 and 1996. All the food items identified by anthropological studies to be consumed frequently in four major regions of Thailand were analysed for volatile nitrosamines using gas chromatography combined with a thermal energy analyser. Relatively high levels of N-nitrosodimethylamine (NDMA), N-nitrosopiperidine (NPIP) and N-nitrosopyrrolidine (NPYR) were detected in fermented fish ("Plasalid"). NDMA was also detected at levels ranging from trace amounts to 66.5 microg/kg in several salted and dried fish ("Larb-pla" and "Pla-siu"). NDMA and NPYR were frequently detected in several vegetables, particularly fermented beans ("Tau-chiau") at levels ranging between 1 and 95.1 microg/kg and 0-146 microg/kg, respectively. The possible role of nitrosamines in Thai food in the aetiology of liver cancer (HCC, CCA) is discussed.
泰国近期的病例对照研究表明，泰国肝癌的高发病率与乙肝感染、黄曲霉毒素摄入和酒精消费等常见风险因素并无关联。虽然肝吸虫华支睾吸虫（OV）感染是泰国东北部肝癌高发的原因，但在该国其他肝癌发病率也很高的地区却不存在这种感染情况。病例对照研究表明，食物中接触外源性以及可能的内源性亚硝胺，以及在槟榔和香烟中接触烟草亚硝胺，可能在肝细胞癌（HCC）的发生中起作用，而OV感染和亚硝胺的化学相互作用也可能是胆管癌（CCA）发生的病因。1988年至1996年间，系统收集并检测了1800多个新鲜和腌制食品样本。对人类学研究确定的泰国四个主要地区经常食用的所有食品，使用气相色谱结合热能分析仪分析其中的挥发性亚硝胺。在发酵鱼（“Plasalid”）中检测到相对较高水平的N-亚硝基二甲胺（NDMA）、N-亚硝基哌啶（NPIP）和N-亚硝基吡咯烷（NPYR）。在几种咸鱼干（“Larb-pla”和“Pla-siu”）中也检测到NDMA，含量从痕量到66.5微克/千克不等。在几种蔬菜中经常检测到NDMA和NPYR，尤其是发酵豆类（“Tau-chiau”），含量分别在1至95.1微克/千克和0至146微克/千克之间。本文讨论了亚硝胺在泰国食物中对肝癌（HCC、CCA）病因学的可能作用。
