Socioeconomic Factors and All Cause and Cause-Specific Mortality among Older People in Latin America, India, and China: A Population-Based Cohort Study

Cleusa Ferri and colleagues studied mortality rates in over 12,000 people aged 65 years and over in Latin America, India, and China and showed that chronic diseases are the main causes of death and that education has an important effect on mortality. Background: Even in low and middle income countries most deaths occur in older adults. In Europe, the effects of better education and home ownership upon mortality seem to persist into old age, but these effects may not generalise to LMICs. Reliable data on causes and determinants of mortality are lacking. Methods and Findings: The vital status of 12,373 people aged 65 y and over was determined 3–5 y after baseline survey in sites in Latin America, India, and China. We report crude and standardised mortality rates, standardized mortality ratios comparing mortality experience with that in the United States, and estimated associations with socioeconomic factors using Cox's proportional hazards regression. Cause-specific mortality fractions were estimated using the InterVA algorithm. Crude mortality rates varied from 27.3 to 70.0 per 1,000 person-years, a 3-fold variation persisting after standardisation for demographic and economic factors. Compared with the US, mortality was much higher in urban India and rural China, much lower in Peru, Venezuela, and urban Mexico, and similar in other sites. Mortality rates were higher among men, and increased with age. Adjusting for these effects, it was found that education, occupational attainment, assets, and pension receipt were all inversely associated with mortality, and food insecurity positively associated. Mutually adjusted, only education remained protective (pooled hazard ratio 0.93, 95% CI 0.89–0.98). Most deaths occurred at home, but, except in India, most individuals received medical attention during their final illness. Chronic diseases were the main causes of death, together with tuberculosis and liver disease, with stroke the leading cause in nearly all sites. Conclusions: Education seems to have an important latent effect on mortality into late life. However, compositional differences in socioeconomic position do not explain differences in mortality between sites. Social protection for older people, and the effectiveness of health systems in preventing and treating chronic disease, may be as important as economic and human development. : Please see later in the article for the Editors' Summary Background: Worldwide, half of all deaths occur in people aged 60 or older. Yet mortality among older people is a neglected topic in global health. In high income countries, where 84% of people do not die until they are aged 65 years or older, the causes of death among older people and the factors (determinants) that affect their risk of dying are well documented. In Europe, for example, the leading causes of death among older people are heart disease, stroke, and other chronic (long-term) diseases. Moreover, as in younger age groups, having a better education and owning a house reduces the risk of death among older people. By contrast, in low and middle income countries (LMICs), where three-quarters of deaths of older people occur, reliable data on the causes and determinants of death among older people are lacking, in part because many LMICs have inadequate vital registration systems—official records of all births and deaths. Why Was This Study Done?: In many LMICs, chronic diseases are replacing communicable (infectious) diseases as the leading causes of death and disability—health experts call this the epidemiological transition (epidemiology is the study of the distribution and causes of disease in populations)—and the average age of the population is increasing (the demographic transition). Faced with these changes, which occur when countries move from a pre-industrial to an industrial economy, policy makers in LMICs need to introduce measures to improve health and reduce deaths among older people. However, to do this, they need reliable data on the causes and determinants of death in this section of the population. In this longitudinal population-based cohort study (a type of study that follows a group of people from a defined population over time), researchers from the 10/66 Dementia Research Group, which is carrying out population-based research on dementia, aging, and non-communicable diseases in LMICs, investigate the patterns of mortality among older people living in Latin America, India, and China. What Did the Researchers Do and Find?: Between 2003 and 2005, the researchers completed a baseline survey of people aged 65 years or older living in six Latin American LMICs, China, and India. Three to five years later, they determined the vital status of 12,373 of the study participants (that is, they determined whether the individual was alive or dead) and interviewed a key informant (usually a relative) about each death using a standardized “verbal autopsy” questionnaire that includes questions about date and place of death, and about medical help-seeking and signs and symptoms noted during the final illness. Finally, they used a tool called the InterVA algorithm to calculate the most likely causes of death from the verbal autopsies. Crude mortality rates varied from 27.3 per 1,000 person-years in urban Peru to 70.0 per 1,000 person-years in urban India, a three-fold difference in mortality rates that persisted even after allowing for differences in age, sex, education, occupational attainment, and number of assets among the study sites. Compared to the US, mortality rates were much higher in urban India and rural China; much lower in urban and rural Peru, Venezuela, and urban Mexico; but similar elsewhere. Although several socioeconomic factors were associated with mortality, only a higher education status provided consistent independent protection against death in statistical analyses. Finally, chronic diseases were the main causes of death; stroke was the leading cause of death at all the sites except those in rural Peru and Mexico. What Do These Findings Mean?: These findings identify the main causes of death among older adults in a range of LMICs and suggest that there is an association of education with mortality that extends into later life. However, these findings may not be generalizable to other LMICs or even to other sites in the LMICs studied, and because some of the information provided by key informants may have been affected by recall error, the accuracy of the findings may be limited. Nevertheless, these findings suggest how health and mortality might be improved in elderly people in LMICs. Specifically, they suggest that efforts to ensure universal access to education should confer substantial health benefits and that interventions that target social and economic vulnerability in later life and promote access to effectively organized health care (particularly for stroke) should be considered. Additional Information: Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001179.