Summary

National mortality statistics were analysed to assess the contribution made by different causes of death to the decline of mortality between 1901 and 1971. Reduced mortality from infectious diseases accounted for about three-quarters of the decrease. The main influence was considered to be improved nutrition, particularly in the case of airborne infections. Reduced exposure to microorganisms, especially those causing gastro-intestinal disease, also played a significant part. Immunization and therapy made only a small contribution. The fall in mortality from noninfectious conditions, accounting for one-quarter of the total decline, owed a good deal to specific medical measures but was also influenced considerably by general improvements in the standard of living, particularly in respect in respect of infant feeding and care.