Completed Research

Select Research

The association between socioeconomic status and adult mortality in a developing country: Evidence from a nationally representative study of Indonesian Adults
Journals of Gerontology: Social Sciences (2017)
Nikkil Sudharsanan
More information

Across developed countries, more educated and affluent individuals tend to live longer than the poor.  Despite the large body of work in developed countries, there is little research on adult mortality inequalities in developing countries, where research on mortality has historically focused on children. Given the large contextual differences between developed and developing countries, insights on the extent and causes of mortality inequality from developed countries may not translate to developing countries. Using a large national data set from Indonesia — the fourth most populous country and the third most populous developing country – I combine information across a wide range of adult ages to provide new estimates of SES differences in adult mortality for a country where adult diseases are the leading causes of death. I also take advantage of measured biomarker and anthropometric data and information on health behaviors to estimate the contribution of major behavioral risk factors for adult mortality (hypertension, unhealthy weight, and tobacco use) to SES differences in adult mortality. I find that mortality inequalities in Indonesia are complex, and depend on sex and the type of SES measure used. For both rural and urban men, there are modest inequalities in adult mortality across an asset-based wealth index, but not across expenditure quartiles. In contrast to men, I find little evidence of inequality for women. Second, I find that risk factors for adult mortality are inconsistently patterned across SES groups and do not explain SES differences in adult mortality. Overall, the associations between SES and adult life expectancy in Indonesia are moderate when compared to developed countries. In a context where behavioral risk factors are inconsistent across SES groups, mortality inequality may be driven by inequalities in health care access or other social factors.

Limited Common Origins of Multiple Adult Health-Related Behaviors: Evidence from U.S. Twins
Social Science & Medicine (2016)
Nikkil Sudharsanan, Jere R. Behrman, and Hans-Peter Kohler
More information

Health-related behaviors are significant contributors to morbidity and mortality in the United States, yet the empirical evidence on the underlying causes of the vast within-population variation in health-related behaviors is mixed. While many potential causes of behaviors have been identified—such as schooling, genetics, and environments—little is known on how much of the variation across multiple health-related behaviors is due to a common set of causes. We use three separate datasets on U.S. twins to investigate the degree to which multiple health-related behaviors correlate and can be explained by a common set of factors. Based on the results of both within identical twin regressions and multivariate behavioral genetic models, we find that aside from smoking and drinking, most behaviors are not strongly correlated among individuals. While we find some evidence that schooling may be related to smoking, schooling is not a strong candidate explanation for the covariation between multiple behaviors. Similarly, we find that a large fraction of the variance in each of the behaviors is consistent with genetic factors; however, we do not find strong evidence that a single common set of genes explains variation in multiple behaviors. We find, however, that a large portion of the correlation between smoking and heavy drinking is consistent with common, mostly childhood, environments–suggesting that the initiation and patterns of these two behaviors might arise from a common childhood origin. Research and policy to identify and modify this source may provide a strong way to reduce the population health burden of smoking and heavy drinking.

Population aging, macroeconomic changes, and global diabetes prevalence, 1990–2008
Population Health Metrics (2015)
Nikkil Sudharsanan, Mohammed K. Ali, Neil K. Mehta, and KM Venkat Narayan
More information

Diabetes is an important contributor to global morbidity and mortality. While aging populations and macroeconomic changes are often implicated as reasons for the rising global prevalence of diabetes, the contributions of these factors to the growth in diabetes prevalence over the past 20 years are unclear. We used cross-sectional data on age- and sex-specific counts of people with diabetes by country, national population estimates, and country-specific macroeconomic variables for the years 1990, 2000, and 2008. We first conducted a decomposition analysis to quantify the contribution of population aging to the change in global diabetes prevalence between 1990 and 2008. Next, we used age-standardization to estimate the contribution of age composition to differences in diabetes prevalence between high-income (HIC) and low-to-middle-income countries (LMICs). Finally, we used non-parametric correlation and fixed-effects regressions to examine the relationship between macroeconomic changes and the change in diabetes prevalence between 1990 and 2008. Globally, diabetes prevalence grew by two percentage points between 1990 (7.4 %) and 2008 (9.4 %). Population aging was responsible for 19 % of the growth, with 81 % attributable to increases in the age-specific prevalences. In both LMICs and HICs, about half the growth in age-specific prevalences was from increasing levels of diabetes between ages 45–65 (51 % in HICs and 46 % in LMICs). After age-standardization, the difference in the prevalence of diabetes between LMICs and HICs was larger (1.9 % point difference in 1990; 1.5 % point difference in 2008). We found no evidence that macroeconomic changes were associated with the growth in diabetes prevalence. Population aging explains a minority of the recent growth in global diabetes prevalence. The increase in global diabetes between 1990 and 2008 was primarily due to an increase in the prevalence of diabetes at ages 45–65. We do not find evidence that basic indicators of economic growth, development, globalization, or urbanization were related to rising levels of diabetes between 1990 and 2008.

Race/ethnicity and disability among older Americans
Handbook of Minority Aging (2013)
Neil K. Mehta, Nikkil Sudharsanan, and Irma T. Elo
More information

Disability is responsible for massive social and economic costs to individuals, families, and health care systems. It is a key indicator of population health and is measured, in some form, in most national health surveys, including data collected by the U.S. Census Bureau. Disability, like most health outcomes, varies considerably across demographic subgroups and understanding the sources of these differentials remains an area of active research. This chapter examines racial and ethnic differences in disability in the United States with a focus on their patterns, trends, and determinants.

We begin by presenting a conceptual framework for understanding the determinants of disability at the population level and among U.S. racial and ethnic groups. We next provide a review of recent evidence on racial and ethnic differences in disability, focusing on studies that have used data from nationally representative surveys and the U.S. census. We then focus on evidence for those aged 50 and above.

Our review of the literature indicated that little is known about patterns and trends in racial and ethnic differences in disability during the recent decade (2000-2010). Therefore, we also present empirical evidence from the National Health Interview Survey (NHIS). Although disability encompasses both cognitive and physical manifestations, our focus is on physical disability. Given the increasing number of foreign-born Americans, particular attention is given to the roles of migration and immigration status in influencing racial and ethnic differences in disability.