Longer healthy life, but for how many? Insights on healthy lifespan inequality from the Global Burden of Disease Study

In the last 150 years, in many populations life expectancy has more than doubled, the variation in length of life has decreased, and, as result, more individuals enjoy similarly longer lives (even though with important socio-demographic differences). When it comes to healthy longevity, today more and more people reach older ages in better health than what they used to do only a few decades ago, for many individuals the unhealthy years are getting compressed at the end of life and, overall, healthy life expectancy is increasing globally. But we do not know how many individuals are benefiting from this increase. Indicators of average length of life, such as healthy life expectancy, do not capture the spread, while similar levels of healthy life expectancy can be achieved by different populations: one where most individuals share a similar number of years in good health, or one where few individuals enjoy high numbers of years in good health compared to many others who do not. Here we apply demographic techniques for the analysis of variation to the demography of health to study the fundamental question of the distribution of number of healthy years of life among individuals and the relation between healthy lifespan length and healthy lifespan inequality. We use data from the Global Burden of Disease Study, and we produce the first international landscape of healthy lifespan variation over time and by socioeconomic level of the country.