People’s chances of living longer have been increasing dramatically for decades. But, that seems to have slowed recently, a new worldwide study has found.

The sharpest decline has come in countries that already had the shortest life expectancy, according to researchers from the Johns Hopkins Bloomberg School of Public Health in Baltimore.

They said the slowdown in life expectancy gains does not mean that humans have simply reached their maximum biological life span. Rather, the researchers argue that their findings could mean that recent medical advances have not sustained historic increases in average life expectancy.

“This is not about us hitting the ceiling,” researcher David Bishai said in a Hopkins news release. “The slowdown has been sharpest in countries that have the most life expectancy to gain.”

Bishai is a professor in the school’s Department of Population, Family and Reproductive Health.

“It’s a rebuke to the idea that you can fix global health just by inventing more stuff,” he said. “New health technology has been essential to making strides in life expectancy, of course, but our predecessors in the 1950s were making faster progress with the basics of soap, sanitation and public health.”

In the 1950s, the study found, life expectancy worldwide increased, on average, by 9.7 years in a decade. Since 2000, however, the increase in a decade has been just 1.9 years.

The findings came from life expectancy data from 139 countries, spanning 1950 to 2010.

The investigators found that countries with the longest life expectancy were approaching the maximum life span of 71 to 83. In those countries, the average life expectancy gain of five years in the 1950s was cut roughly in half, to 2.4 years, in the first decade of the 2000s.

The downward trend in life expectancy was even greater in countries with the shortest life spans. There, sizeable gains became sharp declines.

For instance, areas with a life expectancy of fewer than 51 years had seen a 7.4 year increase in life expectancy during the 1950s. However, that was followed by a steady fall in life expectancy. In the first years of the 21st century, those areas experienced a loss of 6.8 years in life expectancy, the study found.

The HIV/AIDS pandemic can be blamed for some of the decline, but the researchers said it’s not the whole story.

“The slowdown in life expectancy gains started before AIDS hit in the 1980s and ’90s and occurred even in regions that did not have big problems with this disease,” Bishai said.

Also, the methods used to calculate life expectancy have changed since the 1950s, but the slowdown in gains continued. According to the researchers, that means there’s probably another factor at work.

They argued that government failures may play a role and global public health efforts must be improved. Providing health technologies isn’t enough, they said.

“Nowadays, the countries with persistently low life expectancy are countries that generally are fragile states — some are not even trying to increase their life expectancy,” Bishai said. “We need to promote political will and social consensus for public health measures in the countries that need it most.

“If the national government is underperforming, public health can act on political will in districts and villages,” he said. “We used to be good at this, and if we can get it back, then I think we can again see the kinds of improvements we were seeing in the 1950s.”

The findings were published recently in the journal BMC Public Health.

More information

The U.S. Centers for Disease Control and Prevention has more on life expectancy in the United States.