Epidemiology and its applications for geriatrics and gerontology in Brazil

O r??pido envelhecimento populacional em pa??ses em desenvolvimento ?? um novo desafio para a sa??de p??blica. Nesses pa??ses, o crescimento da popula????o idosa ocorre em ambiente de pobreza e grande desigualdade social. Nesse ambiente, as exposi????es de risco e as doen??as s??o mais freq??entes, e os recursos para tratamento e reabilita????o s??o mais escassos. A epidemiologia ?? central para as atividades da sa??de p??blica. Estudos epidemiol??gicos produzem evid??ncias cient??ficas, que s??o essenciais para subsidiar pol??ticas voltadas para a sa??de do idoso. No presente trabalho, s??o descritos os principais tipos de estudos epidemiol??gicos (estudos ecol??gicos, seccionais, caso controle e de coorte) e s??o demonstradas algumas de suas aplica????es em sa??de do idoso. Entre as aplica????es da epidemiologia, foram consideradas: (a) vigil??ncia epidemiol??gica; (b) an??lise da situa????o de sa??de; (c) validade e confiabilidade de testes diagn??sticos; (d) hist??ria natural das doen??as; (e) estudos etiol??gicos ou de causas das doen??as; (f) avalia????o de a????es e programas de sa??de. Como exemplo, foram utilizados dados do Projeto Bambu??, que ?? um estudo brasileiro de coorte prospectiva de longa dura????o. De forma complementar, foram utilizados dados de hospitaliza????es no ??mbito do Sistema ??nico de Sa??de (SUS). Os resultados apresentados s??o exemplos da utilidade da epidemiologia para examinar as condi????es de sa??de e seus determinantes na popula????o idosaThe population of developing countries is ageing rapidly, bringing new challenges for public health. In developing countries, the growth of the aged population occurs in environment of poverty and great social inequality. In such environment, risk exposures and diseases are more frequent and, on the other hand, the resources for treatment and rehabilitation are scarce. The epidemiology plays a central role for public health. Epidemiologic studies provide scientific evidences that are essential for subsidizing polices toward the elderly health. In this paper, some types of epidemiological studies are described (ecological, cross-sectional, case-control and cohort studies), as well as some of their uses. Among the uses of epidemiology, the following were considered: (a) surveillance; (b) health survey; (c) validity and reliability of diagnostic tests; (d) natural history of diseases; (e) causes of diseases; (f) evaluation of effectiveness. We used data from a long term Brazilian cohort study of older adults (the Bambui study), as well as data from public hospitalizations in Brazil as examples. The results of these studies are examples of the usefulness of the epidemiology to investigate the distribution of health-related conditions in the aged population, as well as their determinants