Mortality trends and setbacks: global convergence or divergence?

Health trends over much of the past century have been generally, and notably, positive throughout the world. In several regions, however, life expectancy has declined over the past 1-2 decades. This trend suggests that the expectation that emerged in the 1960s and 1970s of worldwide gains and convergence in population health status is not guaranteed by a general deterministic process. National populations can now be clearly grouped into those that have achieved rapid gains in life expectancy; those whose gains are slower or are perhaps plateauing; and those in which the trends have reversed. Over the past two centuries, outside times of war and famine, such reversals have been rare. Exploration of these varied population health trends elucidates better the close relation between population health and the processes of economic, social, and technological change. Such analysis has shown that the health status of human populations should be a guiding criterion in the debate on sustainable development.