Smoking and lung cancer: foundation of modern epidemiology

Cheong, Hae Kwan

Abstract

Since its introduction to western world in 16th century, smoking has been one of the most popular parts of human life. Its health hazards, however, has rarely been evaluated before mid 20th century. After early suggestion of association with lip cancer and pipe smoking, which was falsely associated with the heat of the pipe smoking, association between rapidly increasing incidence of lung cancer and increasing popularity of smoking habit in the western world has been suggested in late 1940s. Initial case-control studies, in spite of its proneness to various biases, aroused the relevance of the relationship. It was supported by following well-designed case-control studies and new method, cohort studies in both coast of the Atlantic. Consistency of the results of epidemiologic studies and additional support from animal experiments made the causal relationship to be accepted from scientific community, and finally from public and governments. Establishment of criteria of causal relationship was also established in the process of investigation of the relationship between smoking and lung cancer. Smoking is most common cause attributable to lung cancers in most of the world. It is also responsible for the many cancers, including larynx, bladder, oral cavity, esophagus, pancreas, kidney, stomach, liver, and myeloid leukemia; and cardiovascular disorders, respiratory disorders, and other degenerative disorders. Passive (or environmental tobacco) smoking has also been found to be hazardous. Establishment of causal relationship between smoking and lung cancer has been a landmark in the development of epidemiologic methods and concepts, which played the key role in the evaluation of risk factors and preventive intervention on the chronic degenerative disorders.