Laboratory

Population Health

At a Glance Projects Publications Team

Project

Inequalities in Multimorbidity (Dissertation)

Anastasia Lam (MPIDR / University of St Andrews, School of Geography and Sustainable Development, United Kingdom), Mikko Myrskylä, Katherine Keenan (University of St Andrews, School of Geography and Sustainable Development, United Kingdom), Hill Kulu (University of St Andrews, School of Geography and Sustainable Development, United Kingdom)

Detailed Description

The burden of multimorbidity (defined as two or more coexisting chronic diseases) is increasing globally as populations age. Existing research on multimorbidity has mainly been cross-sectional and prevalence-based, and it has focused on high-income countries although rates of chronic diseases and related mortality are highest in low- and middle-income countries. It is uncertain how many years someone is anticipated to live with multimorbidity and how it varies by social and economic conditions. Also, studies comparing countries at varying levels of development are lacking to determine how multimorbidity progression might differ.

In this project, we aim to gain a better understanding of the factors that contribute to inequalities in the development and progression of multimorbidity. We are interested in learning who faces the greatest burden of multimorbidity (i.e., people and countries) and what factors (e.g., gender, education, race, birth cohort) contribute most to the observed inequalities. This is done through several pathways, of which we have completed the first two. First, we estimated the time spent living with multimorbidity (multimorbid life expectancy) in South Africa, where its apartheid history adds further complexity to the relationship between multimorbidity and race, socioeconomic status, and gender. Second, we took a demographic, population-based, cross-national approach to investigate multimorbid life expectancy with and without disability in Costa Rica, Mexico, and the United States. This provides a regional comparison of countries at different stages of the health transition. Third, we plan to investigate if there are differences in the development of multimorbidity across birth cohorts in South Korea.

This project draws on the South African National Income Dynamics Study and on the Gateway to Global Aging Data. Both are nationally-representative longitudinal surveys that collect data on, for example, demographic characteristics, health and health care utilization, socioeconomic status, and family structure. We apply advanced demographic methods, such as discrete-time multistate Markov models and age-period-cohort analysis, to estimate both the time spent living with multimorbidity and the effect that birth cohort might have on multimorbidity development.     

One key finding is that women consistently have a higher multimorbid life expectancy than men in Costa Rica, Mexico, South Africa, and the United States. There are large inequalities in multimorbid life expectancy across race and education in South Africa and in disability-free multimorbid life expectancy between the United States and Costa Rica. In the United States, disability-free multimorbid life expectancy increases, and disabling multimorbid life expectancy declines with rising educational attainment.

This project identifies widespread inequalities in multimorbidity across various domains and within and between countries. But more attention must be paid to the drivers of these disparities, such as life course and health system differences across contexts, and it must be highlighted that interventions should be implemented in a manner proportional to need.

Publications

Lam, A. A.; Keenan, K.; Cezard, G.; Kulu, H.; Myrskylä, M.:

Inequalities in disability-free and disabling multimorbid life expectancy in Costa Rica, Mexico, and the United States

MPIDR Working Paper WP-2023-002. (2023)    

Lam, A. A.; Keenan, K.; Myrskylä, M.; Kulu, H.:

Multimorbid life expectancy across race, socioeconomic status, and gender in South Africa

MPIDR Working Paper WP-2022-024. (2022)