Average remaining lifetimes can increase as human populations age

Increases in median ages, the most commonly used measure of population ageing, are rapid in today's wealthier countries, and population ageing is widely considered to be a significant challenge to the well-being of citizens there. Conventional measures of age count years since birth; however, a...

Full description

Saved in:
Bibliographic Details
Published in:Nature 2005-06, Vol.435 (7043), p.811-813
Main Authors: Sanderson, Warren C, Scherbov, Sergei
Format: Article
Language:English
Subjects:
Adult
Age
Age Distribution
Aged
Anthropology. Demography
Biological and medical sciences
Germany - epidemiology
Human physiology applied to population studies and life conditions. Human ecophysiology
Human populations
Humanities and Social Sciences
Humans
Japan - epidemiology
letter
Life expectancy
Life Expectancy - ethnology
Life Expectancy - trends
Lifetime
Longevity
Medical sciences
Models, Statistical
multidisciplinary
Population
Science
Science (multidisciplinary)
Statistical analysis
Time Factors
United States - epidemiology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Increases in median ages, the most commonly used measure of population ageing, are rapid in today's wealthier countries, and population ageing is widely considered to be a significant challenge to the well-being of citizens there. Conventional measures of age count years since birth; however, as lives lengthen, we need to think of age also in terms of years left until death or in proportion to the expanding lifespan. Here we propose a new measure of ageing: the median age of the population standardized for expected remaining years of life. We show, using historical data and forecasts for Germany, Japan and the United States, that although these populations will be growing older, as measured by their median ages, they will probably experience periods in which they grow younger, as measured by their standardized median ages. Furthermore, we provide forecasts for these countries of the old-age dependency ratio rescaled for increases in life expectancy at birth. These ratios are forecasted to change much less than their unscaled counterparts, and also exhibit periods when the population is effectively growing younger.
ISSN:0028-0836
1476-4687
DOI:10.1038/nature03593