Dynamics of life expectancy and life span equality

Area of Science:

• Demography
• Public Health
• Gerontology

Background:

• Modern civilization has achieved longer lifespans and more similar ages at death over two centuries.
• Recent trends show occasional divergence between life expectancy and lifespan equality, complicating analysis.
• Understanding the dynamic relationship between these demographic indicators is essential for public health policy.

Purpose of the Study:

• To develop a unifying framework for studying life expectancy and lifespan equality over time.
• To analyze the dynamic relationship between life expectancy and lifespan equality using empirical data.
• To identify the impact of mortality reduction at different age groups on these demographic measures.

Main Methods:

• Utilized the Human Mortality Database for 49 countries and regions, with a focus on Sweden's long time series.
• Employed concepts of pace and shape of aging to model the relationship.
• Examined three different measures of lifespan variability.

Main Results:

• Both life expectancy and lifespan equality changes are weighted sums of mortality reduction rates.
• The influence of mortality reductions on these measures varies by age and evolves over time.
• The relationship between life expectancy and lifespan equality is strongest when life expectancy is below 70 years.
• Divergent trends in recent decades are linked to improvements at older ages or stalled declines in midlife mortality.

Conclusions:

• Reductions in mortality at younger ages are most effective in increasing both life expectancy and lifespan equality.
• The findings provide a framework for understanding and potentially guiding public health interventions.
• Targeting mortality declines below current life expectancy is key to simultaneous advancement.