Impact of education, income and chronic disease risk factors on mortality of adults: does ‘a pauper-rich paradox’ exist in Latin American societies?
Received 11 March 2009; received in revised form 27 October 2009; accepted 18 November 2009. published online 28 December 2009.
Summary
Objectives
To test the hypothesis that an inverse association exists between socio-economic position and all-cause mortality in a developing country in Latin America.
Study design
Prospective cohort study carried out in Chile using data from a simple random sample of 920 apparently healthy subjects (weighted population 11,600 aged 30–89 years) followed for 8 years.
Methods
Education level (0–8 years, 9–12 years and ≥13 years) and income quartiles were established at the outset of the study, along with behavioural and biological risk factors for chronic diseases: smoking, alcohol use, obesity, diabetes, hypertension, lipids and family history of death by cardiovascular disease. Relative risks of all-cause mortality were estimated using age-adjusted Cox regression models.
Results
During the follow-up period, 46 deaths were observed. Adjusting for age, gender, and behavioural and biological risk factors, the mortality risk for increasing categories of education after controlling for income was 1.0, 0.76 and 0.33 (P for trend<0.01). In contrast, the relative risk for increasing levels of income after controlling for education was 1.0, 0.98, 1.33 and 1.17 (P for trend=0.07).
Conclusion
While education level had a protective effect on mortality risk of Chilean adults, income had a slightly unfavourable effect on survival. This finding is described as suggestive of a ‘pauper-rich paradox’, since the higher income quantiles in this study correspond with the lower income levels in most developed countries. Nevertheless, due to the small number of deaths, additional research is required to assess the validity of these findings.
dPreventive Medicine and Biometrics, University of Colorado, Health Sciences Center, Denver, CO, USA
eDepartment of Cardiology, Internal Medicine Service, Regional Hospital, Rancagua, Chile
fHealth Center of Mostazal, San Francisco de Mostazal, Chile
Corresponding author: Department of Family Medicine, Faculty of Medicine, University of Chile, 3100 Gran Avenida, San Miguel, Santiago, Chile. Tel.: +56 2 555 2716; fax: +56 2 556 3211.
ABSTRACT