Smoking: the cause of human lung cancer

Abstract

Background. Some investigations found a strong association between smoking, particularly of cigarettes, and human lung cancer, the other not. The basic relation between smoking (nicotine) and human lung cancer still remains uncertain.
Methods. Sir William Richard Shaboe Doll, (28 October 1912–24 July 2005), analysed the relationship between smoking and human lung cancer in his historically important case-control study. Doll found that 647 of 649 lung cancer cases were smokers. In contrast to this, 622 of 649 non-cancer controls were smokers. Doll's study was reanalysed using the conditio sine qua non relationship and the mathematical formula of the causal relationship c. These methods are already known since 1989. All P values are one-sided; significance was indicated by a P value of less than 0.05.
Results. Using the conditio sine qua non relationship, it could be proofed that without smoking, particularly of cigarettes, no development of human lung cancer. On the other hand, using the mathematical formula of the causal relationship c, it could be proofed that smoking, particularly of cigarettes, is at the same time the cause of human lung cancer.
Conclusions. Without smoking, particularly of cigarettes, no development of human lung cancer. Smoking, particularly of cigarettes, is the cause of human lung cancer. Not smoking, particularly of cigarettes, will prevent from human lung cancer.