"The fact that our results highlight such a large impact that is directly attributable to Covid-19 shows how devastating a shock it has been for many countries," Dr Ridhi Kashyap, co-lead author of the paper, published in the International Journal of Epidemiology said.
Life expectancy fell by more than six months compared with 2019 in 22 of the 29 countries analysed in the study, which spanned Europe, the United States and Chile. There were reductions in life expectancy in 27 of the 29 countries overall.
There were greater drops in life expectancy for men than women in most countries, with the largest decline in American men, who saw life expectancy drop by 2.2 years relative to 2019.
In the United States, the rise in mortality was mainly among those of working age and those under 60, while in Europe, deaths among people aged over 60 contributed more significantly to the increase in mortality.