The onset of the great coronary heart disease epidemic of the mid-twentieth century was marked by concern and confusion about this new and highly fatal disease. Clinical medicine and traditional public health measures provided few effective methods of treatment and prevention. The most useful knowledge came from vital statistics and the risk factors of the life insurance industry.

Disease Classification Systems

Severe chronic diseases, including heart disease, became more important causes of death in the early twentieth century as more people survived to old age. This produced a demand for accurate statistics about their incidence, prevalence, and trends, which in turn created new problems for the system of disease classification used for reporting deaths.

Statistical analyses of mortality patterns require a system of disease classification that enables physicians to file accurate and consistent death certificates. The first widely used system was devised by William Farr (1807– 1883), an English public health official, after the inaugural International Statistical Conference at Brussels in 1853. It was later called the International List of Causes of Death and was revised at decadal intervals. The most significant revision occurred in 1893 and created a new classification of 161 diseases that, according to Lancaster, was a “synthesis of English, German and Swiss classifications used by the city of Paris and was based on the principle, introduced by Farr, for distinguishing between general diseases and those localized to a particular organ or anatomical site.” This revision was adopted in almost all western nations, including the United States. Responsibility for subsequent revisions devolved successively on the French government, the League of Nations, and the World Health Organization. In 1949 the system was renamed the International Classification of Diseases.