In making international comparisons, politicians, social scientists, medical research- ers, and others typically divide the world into two broad groups: the more devel- oped nations and the less developed nations. Essentially, this division reflects the economic status of the various nations. The more developed nations are primarily defined by their relatively high gross national income (GNI) per capita compared with the less developed nations. In addition, the more developed nations are char- acterized by diverse economies made up of many different industries, whereas the less developed nations have far simpler economies, and in some cases still rely heavily on extractive industries such as mining or logging or a few agricultural products such as rubber or bananas. These economic differences—primarily resulting from centuries of exploitation by political and economic powers in the more developed nations—have left the less developed nations with high infant and maternal mortality, low life expectancies, and damaging levels of infectious and parasitic diseases.
That said, the less developed nations also differ substantially from each other. Sociologists and other researchers use the term least developed nations to refer to those less developed nations that suffer from the least diverse economy and low- est GNIs and life expectancies. For example, life expectancy in Ethiopia is only 65 years, and gross national product per capita is only $1,730. Table 4.1 compares life expectancies and infant mortality rates in the least, less, and more developed nations. As is common in the field, except when directly comparing the less and least developed nations, this textbook uses the former term to refer to both groups.
Although dividing the globe into least, less, and more developed nations is a useful analytic tool, it is important to recognize that development level is a scale, not a dichotomy. Mexico and Thailand, for example, fall near the border between the more and less developed nations: Each has both complex industries and traditional agricultural crops, and each enjoys infant mortality rates and life expec- tancies approaching those found in the United States. And although infectious and parasitic diseases remain more common in Mexico and Thailand than in the United States, chronic diseases are now the most common cause of death in all three nations.
This terminology also should not keep us from recognizing that social conditions and hence health patterns vary from community to community and from social group to social group within each nation. Thus, conditions in central Detroit in some ways resemble those in Bangladesh, whereas condi- tions in wealthy sections of Bangkok resemble those in Beverly Hills. Within the less developed nations, the income gap—and consequently the “health gap”—between rich and poor has increased in the past two decades. These growing gaps in income and health largely stem from “structural adjustment” policies that have been heavily promoted by international organizations based in the most developed nations.