Changes in Infant and Child Mortality Rates

Abstract

THE increase in average length of life since 1900 equals the increase during the previous hundred years. This remarkable achievement has followed from the application of the principles of sanitation, a rise in the general level of living, and, in certain instances, discoveries in prophylactic and therapeutic medicine, all of which have resulted in a sharp decline in the mortality rates of infancy, childhood, and early adult life. In 1900 the expectation of life at birth was 49 years; in 1935 it was 61 years-an increase of 12 years or nearly 25 per cent. One-third of this increase, namely 4 years, is the result of the decline in infant mortality. In other words, even if there had been no change in the mortality rates among persons one year of age and over between 1900 and 1935, the decrease in infant mortality during that period was sufficient to increase the expectation of life at birth by 4 years. If similar calculations are made using the mortality rates in 1935 of children less than 6 years of age and the 1900 mortality rates for persons 6 years and older, the expectation of life at birth would be 7 years greater than that in 1900, a difference equal to nearly 60 per cent of the actual increase from 1900 to 1935. Before proceeding to a discussion of the changes in infant and child mortality rates since 1930, it is essential to point out that the basic statistical data contain certain errors which affect the trend in mortality rates.' With the admission of Texas to the death registration area in 1933, birth and mortality data for the entire United States became available for the first