Introduction: Debate Concerning the Effects of Smoking on Health

Abstract

Laymen and medical professionals alike often ask questions regarding the cause of cancer and coronary heart disease (CHD), the two major killers in present-day civilization, expecting a simple answer like “smoking causes cancer and coronary heart disease.” Or cholesterol, produced by an unwise diet, may be blamed. It need hardly be argued that to look for single causes for complex phenomena is not a meaningful occupation, particularly when it is obvious that smoking (or the failure to use polyunsaturated fats) is neither a sufficient nor a necessary cause of lung cancer and the other diseases associated with smoking. Out of 10 heavy smokers, only one will die of lung cancer; hence, clearly, smoking is not a sufficient cause; there must be many other factors that, possibly in conjunction with smoking, produce a final result of death from lung cancer. Similarly, smoking is not a necessary cause; at least 1 in 10 people who die of lung cancer is a non-smoker, and among the Mongoloid races, the figure drops to about 1 in 2 (Eysenck, 1965, 1986). Likewise, many people who die of CHD are non-smokers. Thus, there clearly is a highly complex net of causal factors, and a stress on only one of these is scientifically meaningless, particularly if their interaction is synergistic (multiplicative).