In a recent study published in the Scientific Reports Journal, researchers compared the expected and actual changes in life expectancy from 2019 to 2020 to assess the coronavirus disease 2019 (COVID-19)-related loss of life expectancy in 27 countries.
Study: The effect of the COVID-19 pandemic on life expectancy in 27 countries. Image Credit: ANDREI_SITURN/Shutterstock.com
The COVID-19 pandemic was one of the most significant public health crises recently, with nearly 600 million cases worldwide and around six million deaths.
However, it is believed that with COVID-19 testing being insufficient and a significant number of mortalities going unreported, the actual mortality rate is higher than what was estimated.
Furthermore, the effect of COVID-19 on various other comorbidities and inconsistencies in classifying COVID-19-related deaths make it challenging to estimate the COVID-19 mortality rates accurately.
Since life expectancy is not affected by age structure or population size and is age-standardized, many studies have used comparisons between life expectancies in 2019 and 2020 to estimate the impact of COVID-19 on mortality rates.
The results indicate that COVID-19 had a significant impact in lowering life expectancy in 2020, with men and racial minorities being disproportionately affected.
However, this method does not account for the intrinsic variations in life expectancy throughout the year due to mortality variations over time, and the year-on-year variations in mortality have to be accounted for to obtain an accurate estimate of the impact of COVID-19 on life expectancy.
About the study
In the present study, the researchers used an improved method for assessing the loss of life expectancy due to COVID-19 while considering the effects of profound and unexpected events on changes in mortality rates.
They used the Lee-Carter model to project the mortality trajectory for 2020, which was then used as a baseline for measuring the impact of COVID-19 on mortality.
The data from the Eurostat, Human Mortality Database, and the Office of National Statistics of the United Kingdom were used to analyze and estimate the life expectancy changes for 27 chosen countries based on the data availability.
These countries were also the earliest affected after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread outside China. The countries included in the study were Canada and the United States (U.S.) from North America, Australia, Japan, Chile, and 22 European countries.
Life tables were constructed for all 27 countries using the mortality data, and life expectancies were estimated for ages 15 and 65 for both sexes since 15 is a significant age in terms of fertility and participation in the labor force, and 65 years is considered the minimum age to be defined as elderly.
The advantage of the Lee-Carter model in projecting life expectancies lies in its ability to consider variations in mortality data from the past years, the minimum involvement of subjective judgment in the process, and its effective model parameter interpretations.
The Lee-Carter model is believed to estimate the loss of life expectancy better since it not only considers the actual decline in life expectancy in 2020 but can also consider the other possible life expectancy variations in the absence of COVID-19.
The model used mortality data since 1990 (except for Chile, which was since 1992) to project the life expectancy trajectory for 2020.
The results indicated that in the absence of COVID-19, the life expectancies in 21 out of the studied 27 countries would have increased in 2020.
Based on the expected changes in mortality between 2019 and 2020, the loss of life expectancy due to COVID-19 in the 27 countries was estimated to be 1.33 years at 15 years of age and 0.91 years at age 65.
These findings indicated that after considering the intrinsic variations across the years, the impact of COVID-19 on mortality was stronger than previously estimated, especially for those countries that had recently been experiencing an increase in life expectancy.
The loss of life expectancy for the 27 countries estimated in the present study was also higher than those reported by previous studies that did not consider the intrinsic variations across the years.
Previous studies reported the loss of life expectancy in the U.S. to be between 1.18 and 1.87 years, while the present study estimated it to be 2.33 years at age 15. Similar increases in the estimates for loss of life expectancy were observed for England and Wales, Italy, Spain, Poland, Bulgaria, and Slovakia.
Furthermore, while the estimates for Switzerland, Denmark, and Belgium were not more significant than previous estimates, the impact of COVID-19 on mortality was primarily underestimated by previous studies.
Overall, based on comparisons between actual life and expected expectancy changes for 2019 and 2020, the findings from this comprehensive assessment of the impact of COVID-19 on mortality suggested that the loss of life expectancy in 2020 due to COVID-19 was more profound than estimated by previous studies, even in high-income countries.