The influence of socioeconomic status on the predictive power of self-rated health for 6-year mortality in English and Brazilian older adults: the ELSA and Bambui cohort studies.

ABSTRACT

PURPOSE: There is mixed evidence that socioeconomic status (SES) affects the predictive power of self-rated health (SRH) for mortality. We sought to compare the predictive value of SRH for 6-year mortality in English and Brazilian older adults, and to assess whether this association varies by SES in these populations. METHODS: Data came from the English and the Bambui (Brazil) cohort studies of aging. Potential confounding variables included sociodemographic characteristics, lifestyle, self-reported diseases, physical functioning, mental symptoms, and selected biomarker measures. RESULTS: Participants were 5183 English and 1499 Brazilians aged 60 years and over. Low health ratings were independently associated with subsequent mortality in both populations. However, the predictive power of poor SRH for death was much higher for English (a population with higher SES level) than for Brazilians (adjusted hazard ratios 4.45 [95% confidence interval, 3.04-6.51] and 1.88 [1.25-2.81], respectively). In both populations, the predictive value of SRH for mortality was higher among those in the highest income tertile. CONCLUSIONS: Our results suggest that the association between SRH and mortality is underestimated in populations and in subgroups of population with low SES level. Further international research is needed to examine the generalizability of this pattern.