A contribuição dos nascimentos e óbitos para o envelhecimento populacional no Brasil, 1950 a 2100

The objective of this study is to examine population aging in Brazil between 1950 and 2100. We apply a method developed by Preston, Himes and Egger (1989) to decompose the variation in the mean age of the population according to three trends: the natural tendency of the population to grow older, and the rejuvenating effects of both births and deaths. We use data from CELADE (2007a, 2007b) for the years 1950 to 2000, and the population projections calculated by CEDEPLAR, scenario BR, for the 2000-2100 period (CEDEPLAR, 2008). The results are consistent with previous literature by suggesting the central role of fertility decline for the aging process, as well as a secondary but growing effect of mortality transition. At the beginning of the demographic transition, when the Brazilian population was young and quasi-stable, the large volume of births prevented the mean age of the population from increasing. In the following decades, the continuing fall in birth rates has resulted in a gradual increase in the mean age of the population, which is expected to rise from 23.4 years in 1950 to 51.1 years by 2100. Gradually, the age structure will tend again to a quasi-stable scenario with little variation in the mean age of the population, particularly due to the effect of deaths, which will partially replace the role of births by excluding individuals at ages older than the mean age. The large-scale replacement of children by elderly in Brazil, which occurred in the span of only a century, will give rise to an aged population, characterized by only modest variations in the age structure, depending on the future of fertility and mortality levels. Therefore, the current strong demand to adjust the economic and social systems due to the new demographic context may cool down in the future as we approach a new quasi-stable scenario.