TORONTO -- More than 28 million additional years of life were lost than expected in 2020, according to a study of upper-middle and high-income countries.

In the study published by the British Medical Journal Wednesday, most of the 37 countries examined had more premature deaths than expected in 2020, with a higher rate found in men compared to women.

The exceptions were Taiwan, New Zealand, Denmark, Iceland, Norway and South Korea.

The countries with the highest rate of excess premature deaths were Russia, Bulgaria, Lithuania and the United States.

The study examined “years of life lost” (YLL) to have a fuller understanding of the impacts of the COVID-19 pandemic, which requires not only counting excess deaths – which is the difference between observed and expected numbers of death from all causes – but also analysis of how premature said deaths are.

YLL is a more detailed tool which measures both the number of deaths and the age at which they occur, which is why the researchers used it to estimate the changes in life expectancy and excess years of life lost from all causes in 2020.

To do so, they compared the observed life expectancy and years of life lost in 2020 to those that would normally be expected based on analysis of historical trends from 2005 to 2019 in 37 upper-middle and high-income countries.

For the period between 2005 to 2019, the rate of life expectancy at birth increased in both men and women in 37 countries studied. However in 2020, there was a decline in life expectancy in both men and women in all countries except for New Zealand, Taiwan and Norway, which saw a rise in life expectancy.

No evidence of a change in life expectancy was found in Denmark, Iceland and South Korea.

The study found that highest decline in life expectancy (in years) was in Russia, with 2.33 years lost in men and 2.14 years lost in women, followed by the U.S. with 2.27 years lost in men and 1.61 years lost in women, and Bulgaria with 1.96 years lost in men and 1.37 years lost in women.

Lithuania, Chile and Spain also had a high decline in life expectancy.

YLL declined in most countries in both men and women between 2005 and 2019, except for Canada, Greece, Scotland, Taiwan and the U.S., the study says.

In 2020, YLL were higher than expected in all 37 countries studied except Taiwan and New Zealand, where there was a reduction in years of life lost. Iceland, South Korea, Denmark and Norway showed no evidence of a change in years of life lost, according to the study.

In the remaining 31 countries studied, more than 222 million years of life were lost in 2020, which is 28 million more than expected, measured at 17.3 million years lost in men and 10.8 million years lost in women.

The highest excess years of life lost per 100,000 were in Russia, Bulgaria, Lithuania and the U.S., which lost a range of 7,020 to 4,350 years in men and 4,760 to 2,430 years in women. 

The study says that, overall, the excess years of life lost to the COVID-19 pandemic in 2020 (2,510 per 100,000) were more than five times higher than those associated with the seasonal influenza epidemic in 2015 (458 per 100,000).

Excess years of life lost were relatively low in people younger than 65, the study notes, except in Russia, Bulgaria, Lithuania and the U.S., where the excess years of life lost were more than 2,000 per 100,000.

Despite the limitations of the study, which did not include data from most countries in Asia, Africa and Latin America due to lack of data and did not factor in variables such as socioeconomic status, race or ethnicity, the researchers say their findings are “robust.”

“Our findings of a comparable or lower than expected YLL in Taiwan, New Zealand, Denmark, Iceland, Norway, and South Korea underscore the importance of successful viral suppression and elimination policies, including targeted and population based public health policy interventions,” the researchers wrote.