Volatile nitrosamines and tobacco-specific nitrosamines in the smoke of Thai cigarettes: a risk factor for lung cancer and a suspected risk factor for liver cancer in Thailand

In Thailand, smoking of commercial cigarettes and of handmade cigarettes ha s drastically increased in recent decades. Cancer of the lung and of the up per aerodigestive tract have also increased in Thailand as they have in man y other countries. It is our working hypothesis that the increase of primar y cancer of the liver, especially of cholangiocarcinoma in the north-easter n provinces of Thailand is associated with the use of tobacco in men infest ed with the liver fluke Opisthorchis viverrini (OV), Bioassays have shown t hat volatile nitrosamines and tobacco-specific nitrosamines induce cholangi ocarcinoma in laboratory animals and that the hepatocarcinogenic action of nitrosodimethylamine in hamsters is significantly increased by infestation with the liver fluke OV, The endogenous formation of nitrosamines is signif icantly increased by OV infestation, This report presents analytical data o n the concentration of volatile nitrosamines and tobacco-specific nitrosami nes in mainstream smoke of nine leading brands of commercially produced Tha i cigarettes which represent similar to 85% of the market share in Thailand . Observed ranges (ng/cigarette) were 8.5-31.9 for nitrosodimethylamine, 8. 8-49.6 for nitrosopyrrolidine and 4.2-18.9 for nitrosodi-n-butylamine. Thes e values are exceptionally high compared with the smoke of light and blende d cigarettes from North America and Western Europe. Among the tobacco-speci fic nitrosamines, the range was 28-730 for nitrosonornicotine and 16-370 fo r 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. There was a correlation b etween volatile and tobacco-specific nitrosamines, and tar and nicotine del iveries in the mainstream smoke. The analytical data are in line with the r ate for lung cancer and support our working hypothesis that nitrosamines, a nd especially the tobacco-specific nitrosamines, are associated with the in creased risk for primary liver cancer among those Thai people who smoke cig arettes and also carry OV infestation.