[Current trends in the epidemiology of smoking, passive smoking and lung cancer]

In this review of new developments in the field of "smoking and health", three questions are more closely analyzed. The first concerns the health consequences of passive smoking. Based on the example of bronchial carcinoma, evidence is shown on which independent expert committees have come to the conclusion that a causal relationship has to be accepted as probable. A graph is presented showing that among more than a dozen epidemiologic studies, most point clearly to a dose response relationship. In addition it has been shown that passive smoking involves mainly inhalation of sidestream smoke containing significant amounts of carcinogens. The second question concerns the trend of smoking habits in Switzerland. Among men, the proportion of smokers has dropped from at least 60 to 70% in the nineteen fifties to 40% today, and among women, a downward trend has also been observed in recent years. Finally, lung cancer rates have started to decline in several countries and levelled off among men in Switzerland. A decline of the proportion of smokers and a reduction of the tar content of cigarettes by the tobacco industry are seen as principal factors in this development.