The demographic transition in low income countries (cont.)
The causes of modern demographic transitions – mortality decline
There has been considerable debate surrounding the cause of the decline in mortality in modern demographic transitions. It is likely that some combination of the following causes is responsible.
Socioeconomic development
There is a strong relationship between GDP per capita and life expectancy. This has led some to suggest that socioeconomic development as the primary cause of the transitions in low income countries. However Samuel Preston (1975) showed that over time the relationship between GDP per capita and life expectancy has shifted upwards. In other words, for a given level of GDP per capita, life expectancy is now higher than it would have been for the same level of GDP per capita in the past. This means that the observed mortality declines could not be entirely due to economic development (although development undoubtedly played a role).
Importation of health technologies
- Medical technologies and public health interventions imported from elsewhere can rapidly reduce mortality.
- The types of medical technology imported (e.g. antibiotics and vaccinations) would affect infectious disease mortality (and thus infant and child mortality) the most. This is what has been observed to have happened.
- An important role of imported health technologies would explain the speed of the mortality declines when compared with historical Europe. While historical Europe gradually reduced mortality through successive discoveries and new technologies over time, an entire package of health technologies could be imported into low income countries simultaneously.