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Lesotho, with a predicted life expectancy of 57.3 years, will have the lowest lifespan by 2040 among the 195 countries and territories analyzed in the report

Impacts of diseases such as diabetes, HIV/AIDS and cancers, as well as risk factors including diet and smoking rates were taken into account by researchers

CNN  — 

Spain will overtake Japan’s long-held position at the top of the world’s life expectancy table by 2040, while the United States is set to take a big fall in rankings, new research finds.

People in Spain will live for 85.8 years on average, marginally edging out expected lifespans in Japan (85.7), Singapore (85.4) and Switzerland (85.2).

The United States will take the biggest drop in ranking of all high-income countries, falling from 43rd in 2016 to 64th by 2040, with an average life expectancy of 79.8.

The US will be overtaken by China, which rises 29 places to 39th in the table.

Americans will live only 1.1 years longer on average in 2040 compared to 2016, well below the average global rise of 4.4 years over that same period.

“Whether we see significant progress or stagnation depends on how well or poorly health systems address key health drivers,” said Kyle Foreman, director of data science at the Institute for Health Metrics and Evaluation (IHME) and lead author of the study.

“The future of the world’s health is not pre-ordained, and there is a wide range of plausible trajectories,” said Forman.

The findings add to a study last month which found that adhering to a Mediterranean diet can prolong people’s lives.

Spain is one of several European countries to offer tax-funded healthcare, with their healthcare system ranked as the seventh best in the world by the World Health Organization.

Neighboring Portugal was the biggest riser in the top 20, forecasted to add 3.6 years to its average life expectancy and rising from 23rd to fifth. Italy moved up one spot from seventh to sixth.

The study, published in the journal Lancet on Tuesday, analyzed data from the 2016 Global Burden of Diseases project, to generate predictions from 2017 to 2040.