Canada is currently among the top-ranked countries in the world when it comes to average life expectancy, but could fall to 27th place by 2040 due to projected improvements in other nations, according to a new study.

In 2016, Canada ranked 17th out of 195 countries, with an average life expectancy of 81.6 years. By 2040, the life expectancy is expected to rise to 83.1, but Canada will rank 27th on the list as life expectancies also improve elsewhere in the world.

According to the study published in The Lancet on Tuesday, China is one of several countries where life expectancies are expected to increase “substantially” over the next two decades.

In 2016, China ranked 68th with an average life expectancy of 76.3 years. If health trends in the country continue, China’s life expectancy is projected to rise to 81.9 years, and it will rank 39th on the global list by 2040.

Other nations expected to see improved lifespans by 2040 include:

-Syria, which has been devastated by years of civil war and currently ranks 137th on the list, with an average life expectancy of 68.2 years. Due to a “conservative model for conflict,” the country is expected to rank 80th on the list in 20 years, with a life expectancy of 78.6 years.

- Nigeria is expected to rank 123rd (with a life expectancy of 74.8) from 157th place (current life expectancy of 65 years).

In contrast, the life expectancy in Palestinian territories is expected to drop the most, from 114th place (71.9 years) to 152nd (72.2 years).

In 2040, Spain is expected to replace Japan at the top of the global list, with an average lifespan of 85.8 years. 

Among high-income countries, the United States is expected to see the biggest drop in rank, falling from 43rd place to 64th by 2040. However, the average lifespan in the U.S. is actually expected to rise over that period, from 78.7 years to 79.8 years. 

In 2016, four of the top 10 causes of premature deaths across the globe were non-communicable diseases (including diabetes, chronic pulmonary or kidney disease and poor health due to obesity) or injuries.

By 2040, eight of the top 10 causes of premature deaths are expected to be ischemic heart disease, stroke, chronic obstructive pulmonary disease (COPD), chronic kidney disease, Alzheimer’s disease, diabetes, road injuries, and lung cancer.

The study, conducted by researchers from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, used data from the Global Burden of Disease (GBD) study to produce the lifespan forecasts and alternative “better” and “worse” scenarios for life expectancies in each of the ranked countries.

The IHME researchers say the top six health indicators that explain most of the forecasts for premature deaths are high blood pressure, high body mass index, high blood sugar, tobacco use, alcohol use, and air pollution.