As longevity increases worldwide, are the ages at which individuals’ health deteriorates becoming increasingly concentrated over time, or more spread out? In a new study (Permanyer et al. 2023), we assess whether morbidity is compressing or expanding in all regions around the globe. We do so by estimating levels and trends of the newly proposed Healthy Lifespan Inequality (HLI) indicators (Permanyer et al. 2022), which measure the variability in the ages at which individuals cease to be in good health.
Overall, high-mortality countries have been successful in increasing average longevity while simultaneously reducing healthy lifespan inequality. This has been the case of sub-Saharan Africa, South Asia, North Africa and the Middle East, or other regions with plenty of room for improvement. Conversely, low- mortality countries have not been very successful in further reducing the variability in healthy lifespans, so it is not clear whether morbidity is compressing or expanding there. Such stagnation might be the result of forces pushing in opposite directions. On the one hand, increases in living standards or the adoption of healthier lifestyles can postpone the deterioration of individuals’ health. On the other hand, screening and prevention programs could lower the age at diagnosis of important diseases (like mental disorders or cancers). Lastly, existing and broadening socioeconomic inequalities can contribute to widening the distribution of ages at which morbidity starts affecting individuals’ health.
The variability in the ages at which morbidity starts can be much larger than the variability in the ages at which individuals die, and this difference increases over time. While age at death is becoming increasingly predictable in longevity vanguard countries, the age at which health starts deteriorating is as uncertain now as it used to be three decades ago – an important finding with consequences for planners aiming to reduce population health inequalities.
