An analysis of excess mortality rates during COVID-19 pandemic in countries with aging populations

By Dr. Chinta SidharthanReviewed by Benedette Cuffari, M.Sc.Oct 23 2022

In a recent JAMA Network Open study, researchers explore the association between excess mortality and economic factors, health, population, and well-being before and during the coronavirus disease 2019 (COVID-19) pandemic.

Study: Association Between Life Expectancy at Age 60 Years Before the COVID-19 Pandemic and Excess Mortality During the Pandemic in Aging Countries. Image Credit: Inside Creative House / Shutterstock.com

Background

According to the World Health Organization (WHO), the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in about 15 million excess mortalities worldwide. Since age is one of the risk factors for increased severity of COVID-19 symptoms and outcomes, excess mortality is considered to be higher in countries with a high aging ratio.

Despite Japan having one of the highest aging ratios, the number of excess deaths in the country during the COVID-19 pandemic was low. The current study investigates the factors that could explain the low number of excess deaths among the elderly in Japan due to SARS-CoV-2 infections.

About the study

The present study used anonymized and publicly available data to analyze associations between 51 covariates and excess mortality before and during the COVID-19 pandemic. The covariates included aging population ratios, vaccination status, life expectancy, lifestyle, lifestyle disease prevalence, lifestyle disease-related deaths, population, mortality by age group, economic factors, and national health policies.

The covariates significantly associated with aging countries and the COVID-19 pandemic include life expectancy at 60 years of age and the percentage of the population that is fully vaccinated.

An ecological study design approach was employed to compare these covariates to the excess mortalities reported by the WHO between January 2020 and December 2021. Factors associated with excess mortality were screened using linear regression models, whereas the strength of the correlations was determined using the Pearson coefficient.

Study findings

Forty aging countries out of the 158 included in the analysis indicated correlations between three factors and excess mortality. These factors included life expectancy at 60 years of age, the proportion of fully vaccinated individuals in the population, and the gross domestic product (GDP) per capita.

Multiple linear regression analyses showed that only life expectancy at 60 years had any significant correlation to excess mortality. However, among other covariates, the probability of mortality due to cancer, cardiovascular diseases, chronic respiratory diseases, or diabetes between the ages of 30 and 70 was strongly associated with excess mortality.

Excess mortality had weak associations with mortality rates in individuals aged five to 14 years and 15 to 60. No association with mortality rates was reported in the age of zero to five group.

While the current study was limited by its descriptive nature and its use of an ecological study design, the results suggest that a longer life expectancy among the elderly in aging countries is indicative of a higher quality of healthcare available to the population, as well as the resilience of these systems to pandemics and other global health care concerns.

Conclusions

The present study investigated the association between excess mortality during the COVID-19 pandemic and healthcare, population, well-being, and economic factors in aging countries. A total of 40 out of the 158 countries examined had a median population age of above 60 years.

Within the 40 countries, life expectancy at 60 years of age, the proportion of fully vaccinated individuals in the population, and the per capita GDP were associated with excess mortality. However, only life expectancy at 60 years showed a significant correlation.

Excess mortality was not associated with mortality rates among children younger than five years and was weakly associated with mortality rates among 15- to 60-year-olds. Thus, countries with higher healthcare quality had lower excess mortality among the elderly.