Twentieth-Century Mortality Declines
Mortality rates have fallen dramatically in much of the world since the early days of the twentieth century, although life expectancy values are still lower than 50 years in a number of the lesser developed countries, particularly in Africa.
Recent estimates for the more developed countries of North America and Europe place the average life expectancy between a low of 73 years for Ireland and a high of 77 to 78 years for Iceland, the Netherlands, Sweden, and Switzerland (Population Reference Bureau 1989). The primary causes of this enormous mortality decline in the Western world lie in the unprecedented measure of control gained over those infectious and parasitic diseases that until quite recently took such a heavy toll, especially among the younger elements of the population (Stockwell and Groat 1984). Indeed, the most significant mortality trend of the twentieth century has been an extremely pronounced decline in the death rate among children under 1 year of age. In the United States, for example, there has been a 50 percent reduction in the total death rate since 1900 (from 17.2 to 8.6), but the infant mortality rate during the same period declined by approximately 94 percent (from 162 to 10 per 1,000). Moreover, there is evidence that declines of a similar or even greater magnitude have occurred in a number of western European countries since the beginning of the twentieth century (Woods et al. 1988). In contrast to the situation at the turn of the century, when infant mortality rates were of the order of 150 or more, a number of western European countries today have singledigit infant mortality rates; and in three countries (Finland, Iceland, and Sweden), out of every 1,000 babies born only 6 fail to survive until their first birthdays (Population Reference Bureau 1989). In addition, an infant mortality rate of less than 6 per 1,000 is found in Japan, the first non-European country to achieve a high level of modernization.In sharp contrast to these single-digit infant mortality rates, or even those approaching 15 throughout more or less developed regions of the globe, infant mortality rates of the order of 100 or more per 1,000 live births are still fairly common in the less developed countries of the Third World.
Today they are highest in the least developed countries of Africa: 18 countries on that continent have rates of 125 or more, and in at least 4 countries (Ethiopia, Guinea, Mali, and Sierra Leone) the infant mortality rate continues to exceed 150 per 1,000 live births (Population Reference Bureau 1989).The high life expectancy values and corresponding low infant mortality rates of the more developed countries stand as an impressive testimony to the success of those countries in improving the quality of life of their populations. Conversely, the low life expectancies and corresponding high infant mortality rates in the less developed countries are, as was the case in Europe a century ago, a reflection of the poor quality of life available to the bulk of the population. In particular, they reflect the inability of existing public health programs to deal with evolving health problems, many of which are related to widespread malnutrition resulting, at least in part, from a decline in social and economic progress (Gwatkin 1980). In other words, on an international level there remains a clear and strong association between level of modernization and the infant mortality rate. In fact, the association is so strong that the infant mortality rate is generally regarded as a much more accurate indicator of the level of socioeconomic well-being of a people than is its per capita gross national product or any of the other more conventional indices of economic development.