If blowing out the candles on your 100th birthday cake is a pillar of your retirement plan, you might want to skip to the next article. An analysis of death data from the world’s longest-lived populations reveals that the rapid improvements in life expectancy achieved in the 20th century have slowed dramatically in the past three decades. The finding suggests that if 100 is to become the new 80, radical new medicines that slow the ageing process itself are needed, rather than better treatments for common killers such as cancer, dementia and heart disease. According to the study, children born recently in regions with the oldest people are far from likely to become centenarians. At best, the researchers predict 15% of females and 5% of males in the oldest-living areas will reach 100 this century. “If you’re planning for retirement, it’s probably not a good idea to assume you’re going to make it to 100,” said Jay Olshansky, professor of epidemiology and biostatistics at the University of Illinois at Chicago. “You’d probably have to work for at least 10 years longer than you’d think. And you want to enjoy the last phase of your life, you don’t necessarily want to spend it working to save for time you’re not going to experience.” Advances in public health and medicine sparked a longevity revolution in the 20th century. In the previous 2,000 years, life expectancy crept up, on average, one year every century or two. In the 20th century, average life expectancy rocketed, with people gaining an extra three years every decade. The period of radical life extension prompted some researchers to extrapolate the trend and suggest most people born after 2000 would survive to 100 years old. But the prospect was challenged in 1990 by Olshansky and his colleagues, who argued that humans were reaching a biological ceiling of about 85 years old. For the latest study, Olshansky delved into national statistics from the US and nine regions with the highest life expectancies, focusing on 1990 to 2019, before the Covid pandemic struck. The data from Hong Kong, Japan, South Korea, Australia, France, Italy, Switzerland, Sweden, and Spain showed that rises in life expectancy had slowed dramatically. In the US, life expectancy fell. Writing in Nature Aging, the researchers describe how on average, life expectancy in the longest-living regions rose only 6.5 years between 1990 and 2019. They predict that girls born recently in the regions have only a 5.3% chance of reaching 100 years old, while boys have a 1.8% chance. “In the modern era we have, through public health and medicine, manufactured decades of life that otherwise would not exist,” Olshansky said. “These gains must slow down. The longevity game we’re playing today is different to the longevity game we played a century ago when we were saving infants and children and women of child-bearing age and the gains in life expectancy were large. Now the gains are small because we’re saving people in their 60s, 70s, 80s, and 90s.” Olshansky said it would take radical new treatments that slow ageing, the greatest risk factor for many diseases, to achieve another longevity revolution. Research in the field is afoot with a dozen or so drugs shown to increase the lifespan of mice. In 2000, Steven Austad, a professor of healthy ageing at the University of Birmingham at Alabama bet Olshansky that the first person to live to 150 had already been born. Thanks to compound interest, by the time the bet is settled, the winner, or his descendants, stands to win millions of dollars. “For life expectancy to again accelerate, we need a new approach focused on disease prevention,” Austad said. “Geroscience focuses on improving health by treating the underlying biological processes of ageing, which underlie virtually all of the maladies that degrade our quality of life or kill us.” “These advances are beginning to make their way to the clinic,” he added. “So as much as I buy this analysis of slowed life expectancy increase, the authors’ projection for a continued gradual slowing for the rest of this century strikes me as premature.” The most recent figures from the Office for National Statistics show that life expectancy at birth in the UK from 2020 to 2022 stood at 82.6 years for females and 78.6 for males, which are back to 2010-2012 levels for females and below that level for males.