Study finds positive association between obesity and COVID-19 mortality across 142 countries

By Pooja Toshniwal PahariaReviewed by Benedette Cuffari, M.Sc.Apr 15 2023

In a recent study published in the journal Scientific Reports, researchers determined the association between coronavirus disease 2019 (COVID-19)-associated deaths and the percentage of obese adults across 142 nations.

Study: Obesity and COVID-19 mortality are correlated. Image Credit: Anatta_Tan / Shutterstock.com

Background

Obese adult individuals are mainly concentrated in relatively high-income nations, whereas low-income nations comprise more significant proportions of lean individuals. Interestingly, the mortality rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are usually higher among more prosperous nations.

Obesity may lead to several chronic medical conditions that could result in death from COVID-19. Furthermore, obesity might increase the duration and volume of SARS-CoV-2 shedding, which may contribute to greater viral transmissibility to others.

Previous studies have reported poorer COVID-19 outcomes and survival probability among overweight individuals infected with SARS-CoV-2. Most studies assessing the relationship between obesity and COVID-19 mortality were conducted at an individual level. As a result, they are subject to greater noise and non-uniformity in terms of their study methodology, design, sample size, and intervention. International-level data on the association between SARS-CoV-2 infection-associated deaths and obesity are limited.

About the study

In the present study, researchers explore obesity as a determinant of country-level variations in mortality rates of SARS-CoV-2 infections.

Data on COVID-19-associated mortality were provided by the European Centers for Disease Control and Prevention (ECDC). Comparatively, data on obese adult proportions were retrieved from the Global Health Observatory (GHO) database of the World Health Organization (WHO). Individuals with body mass index (BMI) values exceeding 30.0 kg/m² were considered obese, whereas those with BMI values between 25.0 kg/m² and 29.9 kg/m² were considered overweight.

Data on population-level parameters, including the proportion of older individuals over the age of 65 years, median participant age, and the percentage of women, were retrieved from population estimates published by the United Nations Population Division. Data on nation-level income, which were categorized as low, lower-middle, upper-middle, and high, were determined by per capita Gross National Income (GNI) estimates of 2019 that were determined through the use of the World Bank’s Atlas classification technique.

Nations with per capita GNI of at least $12,536 constituted high-household income nations, whereas those with per capita GNI between $4,046 and $12,535 were considered upper-middle-household income nations. Nations with per capita GNI between $1,036 and $4,045 were considered lower-middle-household income nations, whereas nations with per capita GNI less than $1,035 were considered low-household income nations.

Multivariate and weighted polynomial-type regression modeling were performed to estimate the link between COVID-19 mortality and obesity.

Results

A significant, positive, and partial relationship was observed between COVID-19-related deaths and the percentage of obese adults residing in 142 nations, irrespective of median participant age, sex, the percentage of older individuals, and the female population. The limits of confidence intervals centered around the point elasticity estimates for COVID-19-associated mortality elasticities among obese adults extended between 0.70 and 2.10.

The predicted elasticity for COVID-19-related mortality regarding the percentage of obese adults was the greatest for high-income nations. On average, each percent point increment in the percentage of obese adults contributed to an additional 1.50% points to SARS-CoV-2 infection-associated mortality among individuals residing in wealthy nations.

A previous study reported that the confidence interval limits computed around the predicted point elasticities concerning the proportion of overweight adults ranged between 0.20 and 5.40. The present study reported more tightly distributed predicted point elasticities that were computed for obese adult individuals compared to those reported for overweight adult individuals.

Conclusions

The study findings showed a positive association between COVID-19-associated mortality and obesity, thus indicating that effective weight management strategies and programs could aid in improving COVID-19 severity outcomes and reducing the health burden of the disease. These findings add to the scientific literature on COVID-19 and highlight the benefit of weight-lowering interventions in preventing death from SARS-CoV-2 infections.

However, the validity of the study findings obtained in an inter-country regression modeling analysis could be questioned, as nations might have limited commonalities that can merit their inclusion in the regression analysis. Additionally, in regard to the credibility of sources that enable access to relevant information, the study findings should be interpreted cautiously since the reliability and quality of information on SARS-CoV-2 infections might be sensitive to the accuracy of documentation, which can vary across nations.