Statistical innovation sheds light on global progress in living longer

When it comes to trends in mortality over the last thirty years, countries around the world can be grouped into five clusters, roughly representing the five continents, according to a new study published January 17, 2024, in the open-access journal PLOS ONE by David Atance of Universidad de Alcalá, Spain, and colleagues. While the clusters follow different trajectories, they share some commonalities, including longer life expectancies and fewer disparities between genders and groups of countries with different mortality and longevity indicators.

Most countries in the world have seen improvements in longevity over the last two centuries, and scientists have wondered whether there is convergence or divergence towards a unique pattern of mortality and longevity across countries. In the new study, Atance and colleagues used new statistical approaches to analyze not only life expectancy at birth, but eight other mortality indicators using data from 194 countries from the United Nations Populations Division records.

The study found that in 1990 and 2010 those countries could be clustered into five groups based on their mortality/longevity characteristics. Several countries changed clusters between the two timepoints-;often based on wars and deleterious socioeconomic and political conditions-;but in general the clusters represent the configuration of continents. Among all convergence clubs and countries, the life expectancy is increasing and the male-female gap in mortality is shrinking. The researchers used their model to predict groupings in 2030 and found continuation of these trends.

The authors conclude that their approach is able to show new insight into the historical evolution of the mortality convergence groupings in the period 1990-2020 and expands their score to include projections of their expected future evolution.