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 behavioral 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 behavioral 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).