Many analysts have argued that the ageing populations of developing nations represent an economic time bomb for future generations who will have to work to support them. But these fears may not necessarily be justified, according to a study in last week's Nature.
Current estimates of a population's age are based on the average number of years that people have been alive. But more important is the number of years they have left to live, point out Warren Sanderson and Sergei Scherbov. So they have redefined the average age by taking into account how life expectancy will change. The system uses 2000 as a reference year, so if the remaining life expectancy of a 30-year-old in 2000 is 50 years, say, and that of a 40-year-old in 2050 is also 50 years, then the future 40-year-old will have a 'standardized' age of 30.
Using this method throws up some interesting predictions, as populations can effectively become 'younger' through increases in life expectancy, as well as through increased birth rates. Sanderson and Scherbov estimate how the proportion of elderly dependents in a society will change over the twenty-first century for Japan, Germany and the United States - three countries thought to be most at risk from ageing. In fact, the researchers argue, the economic burden of elderly people should begin to decline by the end of the century.
More details:
"Average remaining lifetimes can increase as human populations age" Nature 435, 811-813 (9 June 2005)
Related stories:
Stone Age Graveyard reveals Lifestyles of a 'Green Sahara': Two Successive Cultures Thrived Lakeside
(PhysOrg.com) -- The largest Stone Age graveyard found in the Sahara, which provides an unparalleled record of life when the region was green, has been discovered in Niger by National Geographic Explorer-in-Residence and University of Chicago Professor Paul Sereno, whose team first happened on the site during a dinosaur-hunting expedition.
'Don't Worry Be Happy': happiness is key to longer life
Keep humming "Don't Worry Be Happy". The 1980s New Age-inspired hit got it right. New research shows being happy can add several years to life.
Scientists find elephant memories may hold key to survival
A recent study by the Wildlife Conservation Society and the Zoological Society of London (ZSL) suggests that old female elephants—and perhaps their memories of distant, life-sustaining sources of food and water—may be the key to survival during the worst of times.
Wheezing After Early-Life Antibiotics: Blame the Underlying Chest Infection More Than the Antibiotics
(PhysOrg.com) -- Children who are given antibiotics in their first three months often wheeze at 15 months of age. However, this wheezing is probably more due to the presence of chest infections than to the use of antibiotics.
Antarctic fossils paint a picture of a much warmer continent
National Science Foundation-funded scientists working in an ice-free region of Antarctica have discovered the last traces of tundra--in the form of fossilized plants and insects--on the interior of the southernmost continent before temperatures began a relentless drop millions of years ago.
Scientists find new clues to explain Amazonian biodiversity
Ice age climate change and ancient flooding—but not barriers created by rivers—may have promoted the evolution of new insect species in the Amazon region of South America, a new study suggests.
Coronary heart disease patients live longer, but not always happier, lives
Better treatments have improved survival in people with coronary heart disease, but the quality of those extra years may be less than ideal, according to research reported in Circulation: Journal of the American Heart Association.
Exotic Chameleon Spends Most of its Life as an Egg
(PhysOrg.com) -- Scientists have discovered a chameleon species that spends a good two-thirds of its life inside an egg:
Furcifer labordi lives about 8-9 months as an embryo, and has a post-hatching lifespan of just 4-5 months. As far as the scientists know, this strange life history is unique among all land vertebrates, and may help researchers better understand how certain ecological and hormonal factors influence life history evolution.