Lr. Ramos et al., Two-year follow-up study of elderly residents in S Paulo, Brazil: methodology and preliminary results, REV SAUDE P, 32(5), 1998, pp. 397-407
Introduction Previous cross-sectional studies have shown a high prevalence
of chronic disease and disability among the elderly. Given Brazil's rapid a
ging process and the obvious consequences of the growing number of old peop
le with chronic diseases and associated disabilities for the provision of h
ealth services, a need was felt for a study that would overcome the limitat
ions of cross-sectional data and shed some light on the main factors determ
ining whether a person will live longer and free of disabling diseases, the
so-called successful aging. The methodology of the first follow-up study o
f elderly residents in Brazil is presented.
Method The profile of the initial cohort is compared with previous cross-se
ctional data and an in-depth analysis of nonresponse is carried out in orde
r to assess the validity of future longitudinal analysis. The EPIDOSO ('Epi
demiologia do Idoso') Study conducted a two-year follow-up of 1,667 elderly
people (65+), living in S. Paulo. The study consisted of two waves, each c
onsisting of household, clinical, and biochemical surveys.
Results and Conclusions In general, the initial cohort showed a similar pro
file to previous cross-sectional samples in S. Paulo. There was a majority
of women, mostly widows, living in multigenerational households, and a high
prevalence of chronic illnesses, psychiatric disturbances, and physical di
sabilities. Despite all the difficulties inherent in follow-up studies, the
re was a fairly low rate of nonresponse to the household survey after two y
ears, which did not actually affect the representation of the cohort at the
final household assessment, making unbiased longitudinal analysis possible
. Concerning the clinical and blood sampling surveys, the respondents tende
d to be younger and less disabled than the nonrespondents, limiting the use
of the clinical and laboratory data to longitudinal analysis aimed at a he
althier cohort. It is worth mentioning that gender, education, family suppo
rt, and socioeconomic status were not important determinants of nonresponse
, as is often the case.