The Triangular Life Table: a Unified Framework for the Study of Mortality and Morbidity

Chiara Micheletti , Universitat Autònoma de Barcelona - Centre d'Estudis Demogràfics (CED)
Iñaki Permanyer, Centre d'Estudis Demogràfics

Over the past two centuries, populations across the world have witnessed a remarkable surge in life expectancy. Nevertheless, living longer does not guarantee living healthier, sparking a long-standing debate on the relationship between mortality and morbidity. This paper introduces the "triangular life table", an innovative extension to the classic life table, which aims to take into consideration not only the ages at which individuals die, but also those in which they cease to be in full health. We start from the very basic idea that the length of life x can be broken down into a sum of years spent healthy h, and years spent unhealthy u, such that x=h+u. Then, we follow a synthetic cohort of individuals throughout their lives, assuming that at each age they are exposed not only to the observed mortality pattern of a population, but also to its morbidity experience. Instead of calculating rates, probabilities, and other metrics for every age x, we compute them for different combinations of h and u. In this way, we are able to incorporate duration (the time spent in the different health states), overcoming one of the main limitations of classical multistate methods. The tools presented in this paper allow for estimating how individuals’ lifespans are composed of years spent in good and in less-than-good health at age at death. The surfaces and visualisations produced within the triangular framework we propose could help in advancing the knowledge on the complex interplay between mortality and morbidity.

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 Presented in Session 48. Life Table Methods and Decompositions in Mortality Research