Aging in the context of cohort evolution and mortality selection

Area of Science:

• Gerontology
• Demography
• Evolutionary Biology

Background:

• Aging patterns are understood through cohort evolution and mortality selection theories.
• These theories explain variations in mortality rates and their acceleration over the life course across different birth cohorts.

Purpose of the Study:

• To analyze historical cohort mortality data to understand aging patterns.
• To investigate how cohort evolution and mortality selection influence demographic and biological aging rates.
• To explore the implications for human lifespan limits and the evolution of aging.

Main Methods:

• Analysis of historical cohort mortality data.
• Examination of age-specific mortality rates and their changes across birth cohorts.
• Assessment of mortality selection at young and late ages.

Main Results:

• Support found for both cohort evolution and mortality selection perspectives.
• Demographic aging rate (mortality acceleration past age 70) varies across cohorts and is influenced by mortality selection.
• Later cohorts show higher demographic aging rates than earlier cohorts.
• Biological aging rate (senescence process) declined from mid-19th century cohorts and then stabilized.
• Biological aging is affected by young-age mortality changes, not early life mortality selection.

Conclusions:

• Cohort evolution and mortality selection significantly shape aging trajectories.
• Understanding these factors is crucial for studying human lifespan potential and aging evolution.
• Findings provide new insights into the dynamic nature of aging across historical populations.