Our general intention in this paper is to sustain the ongoing debate on the questionable contribution of specific medical measures and/or the expansion of medical services to the observable decline in mortality in the twentieth century.
McKeown, without doubt, has pursued the argument more consistently and with greater effect than any other researcher…
His findings for the nineteenth century are summarized as follows:
[T]he decline of mortality in the second half of the nineteenth century was due wholly to a reduction of deaths from infectious diseases; there was no evidence of a decline in other causes of death.
Examination of the diseases which contributed to the decline suggested that the main influences were;
(a) rising standards of living, of which the most significant feature was a better diet;
(b) improvements in hygiene; and
(c) a favorable trend in the relationship between some micro-organisms and the human host.
Therapy made no contributions, and the effect of immunization was restricted to smallpox which accounted for only about one-twentieth of the reduction of the death rate.
[T]he main influences on the decline in mortality were improved nutrition on air-borne infections, reduced exposure (from better hygiene) on water- and food-borne diseases and, less certainly, immunization and therapy on the large number of conditions included in the miscellaneous group. Since these three classes were responsible respectively for nearly half, one-sixth, and one-tenth of the fall in the death rate, it is probably that the advancement in nutrition was the major influence.
Of the total fall in the standardized death rate between 1900 and 1973, 92.3 percent occurred prior to 1950.
It is evident that the beginning of the precipitate and still unrestrained rise in medical care expenditures began when nearly all (92 percent) of the modern decline in mortality [in the 20th] century had already occurred.
[T]uberculosis, scarlet fever, pneumonia, diphtheria, measles, and typhoid) showed negligible declines in their mortality rates subsequent to the date of medical intervention.
In general, medical measures (both chemotherapeutic and prophylactic) appear to have contributed little to the overall decline in mortality in the United States since about 1900 — having in many instances been introduced several decades after a marked decline had already set in and having no detectable influence in most instances.
More specifically, with reference to those five conditions (influenza, pneumonia, diphtheria, whooping cough, and poliomyelitis) for which the decline in mortality appears substantial after the point of intervention — and on the unlikely assumption that all of this decline is attributable to the intervention — it is estimated that at most 3.5 percent of the total decline in mortality since 1900 could be ascribed to medical measures introduced for the diseases considered here.