The sugar content and the pH of the smoke of cigarette, cigar and pipe tobaccos in relation to lung cancer.

Abstract

AbstractThe risk of lung cancer is greater in cigarette smokers than in cigar or pipe smokers. In Great Britain, which has a very high lung‐cancer death rate, cigarette tobacco (flue‐cured) has a high sugar content (up to 20%) while cigar tobacco (aircured) has a low sugar content (0.5—2%). Determinations of the sugar content of the tobacco and the pH of the smoke of cigarettes from more than 30 countries, and of a number of cigar and pipe tobaccos, have been carried out. The main differences found between the characteristics of cigarette and cigar and pipe tobaccos are: The high sugar content of the popular brands of cigarettes now smoked in many countries, which results in the production of a smoke of acid pH, becoming progressively more acid during the course of smoking, particularly towards the butt‐end of the cigarette when the tar content of the smoke is at its highest; The low sugar content of cigar tobacco and of the air‐dried tobacco used in the cigarettes of certain countries, which gives a smoke of less acid pH becoming progressively more alkaline during the course of smoking; The conditions of smoking in a pipe whereby the smoke from all types of tobacco, with both high and low sugar content, is less acid than that of most cigarettes, and becomes progressively more alkaline during the course of smoking. Since the satisfaction derived from smoking is mainly due to the pharmacological effects of nicotine, it is suggested that the lower lung cancer incidence in cigar and pipe smokers may be related to the fact that nicotine is more readily absorbed in the form of the free base, at alkaline pH, than in the form of a stable salt, at acid pH. To obtain the same degree of “nicotine satisfaction” as in smoking a pipe or cigar, the smoker of cigarettes giving an acid smoke would tend to smoke more, and to encourage more prolonged and extensive contact of the smoke with the mouth and bronchus, and to take the smoke into his lungs, which would thus suffer greater exposure to the “carcinogenic” effects of the smoke than would be the case with cigar or pipe smokers.In preliminary attempts to devise a “safer” cigarette, the addition of substances which give rise to an alkaline vapour at the usual temperature of combustion of cigarettes has been shown to reverse the character of the smoke of high sugar (fluecured) tobacco cigarettes so that it then resembles that of cigars and pipes in becoming progressively more alkaline during the course of smoking.