A evolu？？o do índice de envelhecimento no Brasil, nas suas regi？es e unidades federativas no período de 1970 a 2010

introduction: the aging index (ai) assesses the process of the broadening of the elderly portion of the total population in relation to the relative variation in the young age group, where it is determined by the ratio of the elderly population to the young population. this indicator allows the observation of the evolution of the aging rhythm of the population, comparing geographic areas and social groups, and can thus help in the formulation, management and evaluation of public policies in the areas of health and social welfare. objective: this study aimed to examine the evolution of ai in brazil and its regions and federative units from 1970 to 2010. methods: a descriptive study was conducted using data obtained from the demographic censuses and the social indicators of ibge (brazilian institute of geography and statistics), for the period of 1970 to 2010. results: in 2010, ai in brazil was 44.8. among the brazilian regions, the south (54.94) and southeast (54.59) had the highest ai; and the north (21.84), the lowest. the federative units with the highest ai were rio grande do sul (65.47) and rio de janeiro (61.45). the lowest indices belonged to the states of amapá (15.45) and roraima (16.57). ai in brazil increased 268% during the study period. conclusion: the results show that brazil's population is truly in a process of aging, because from 1970 to 2010, ai showed a progressive increase, also observed in the different regions and federative units of the country.