People in the major industrialized countries will be living longer by the middle of the 21st century than official estimates had predicted, researchers said Wednesday.
The new calculation, by Shripad Tuljapurkar and other scientists at Mountain View Research in Los Altos, Calif., is based on new demographic models of five decades of mortality in the Group of Seven most industrialized countries.
The calculations show, for example, that Japanese life expectancy will increase by eight years to 90.9 by 2050, up from the current prediction of 82.9 years.
"In every country over this period, mortality at each age has declined exponentially at a roughly constant rate," the scientists said in the study. "We find that median forecasts of life expectancy are substantially larger than in existing official forecasts."
The study is reported in the latest edition of the science journal Nature.
According to the estimates, French life expectancy will increase to 87 years instead of 83.5, followed by Italy with 86.2 years (82.5), Canada with 85.2 years (81.6), Britain with 83.7 years (82.5), Germany with 83.1 years (81.5) and the United States with 82.9 years (80.4).
The new estimates also change the ratio of people over 65 to working people in 2050, which ranges from 6% higher in Britain to 40% higher than official forecasts in Japan.
"Being able to predict how these populations will age has enormous implications for the planning and provision of services and support. Small increases in life expectancy translate into large increases in the population," Richard Suzman, the associate director of the National Institute on Aging in the United States, said in a statement.
The institute supported the research.
In a commentary on the research, Shiro Horiuchi of the Laboratory of Populations at Rockefeller University in New York said life expectancy exceeding 80 years will be limited to countries with highly developed market economies, mainly in Western Europe, North America and eastern Asia.
In the rest of the world, life expectancy is still on average less than 65 years, and in sub-Saharan Africa it is less than 50 years.
"Overall, the evidence supports the expectation that scientific, technological and economic developments will lead to more effective control of degenerative disease and aging processes, making it possible to sustain the rapid pace of mortality decline," Horiuchi said.