The association of health and income in the elderly: experience from a southern state of Brazil.
OBJECTIVE
In high income, developed countries, health status tends to improve as income increases, but primarily through the 50(th)-66(th) percentile of income. It is unclear whether the same limitation holds in middle income countries, and for both general assessments of health and specific conditions.


METHODS
Data were obtained from Brazil, a middle income country. In-person interviews with a representative sample of community residents age ≥ 60 (N=6963), in the southern state of Rio Grande do Sul, obtained information on demographic characteristics including household income and number of persons supported, general health status (self-rated health, functional status), depression, and seven physician-diagnosed, self-reported health conditions. Analyses used household income (adjusted for number supported and economies of scale) together with higher order income terms, and controlled for demographics and comorbidities, to ascertain nonlinearity between income and general and specific health measures.


RESULTS
In fully controlled analyses income was associated with general measures of health (linearly with self-rated health, nonlinearly with functional status). For specific health measures there was a consistent linear association with depression, pulmonary disorders, renal disorders, and sensory impairment. For musculoskeletal, cardiovascular (negative association), and gastrointestinal disorders this association no longer held when comorbidities were controlled. There was no association with diabetes.


CONCLUSIONS
Contrary to findings in high income countries, the association of household-size-adjusted income with health was generally linear, sometimes negative, and sometimes absent when comorbidities were controlled.
Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, United States of America ; Geriatric Research, Education and Clinical Center, Veterans Administration Medical Center, Durham, North Carolina, United States of America.
Gerda G
GG
Fillenbaum
Sergio L
SL
Blay
Carl F
CF
Pieper
Katherine E
KE
King
Sergio B
SB
Andreoli
Fábio L
FL
Gastal
D000368:Aged; D001938:Brazil / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000191:economics* / Q000453:epidemiology; D003863:Depression / Q000191:economics* / Q000453:epidemiology; D004522:Educational Status; D005191:Family Characteristics; D005260:Female; D006304:Health Status; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D007674:Kidney Diseases / Q000191:economics* / Q000453:epidemiology; D008171:Lung Diseases / Q000191:economics* / Q000453:epidemiology; D008297:Male; D001523:Mental Disorders / Q000191:economics* / Q000453:epidemiology; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000191:economics* / Q000453:epidemiology; D012923:Social Class