Is BMI Higher in Younger Patients with COVID-19? Association Between BMI and COVID-19 Hospitalization by Age
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Updated: Dec 16, 2025

Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
Ajay Bhasin1, Hannah Nam2, Chen Yeh3
1Department of Medicine, Division of Hospital Medicine, Northwestern Memorial Hospital, Feinberg School of Medicine, Chicago, Illinois, USA.
Insights
Younger patients hospitalized with COVID-19 had higher BMIs than older patients, regardless of diabetes or hypertension. This trend was not observed in non-COVID-19 patients, highlighting obesity as a key factor in severe COVID-19 outcomes.
Area of Science:
- Medical Science
- Epidemiology
- Public Health
Background:
- Obesity is a known risk factor for severe COVID-19 and hospitalization.
- Understanding demographic differences in COVID-19 severity is crucial for public health strategies.
Purpose of the Study:
- To investigate if Body Mass Index (BMI) differences exist between younger and older COVID-19 patients.
- To determine if these BMI trends are independent of diabetes and hypertension.
- To compare BMI trends in COVID-19 patients versus non-COVID-19 patients.
Main Methods:
- Cross-sectional analysis of hospitalized patients with moderate to severe COVID-19.
- Comparison of patients younger than 50 versus older than 50 years.
- Inclusion of patients with and without diabetes and hypertension.
- Comparison with a cohort of patients hospitalized without COVID-19.
Main Results:
- Younger COVID-19 patients (<50 years) without diabetes or hypertension had significantly higher mean BMIs (43.1) than older patients (30.1).
- A trend of inversely correlated BMI with increasing age was observed in COVID-19 patients.
- No significant BMI differences or age-related trends were found in patients hospitalized without COVID-19.
Conclusions:
- Younger individuals with COVID-19 exhibit higher BMIs compared to older individuals, irrespective of comorbidities like diabetes and hypertension.
- Age-related BMI trends in COVID-19 hospitalization are distinct from those in non-COVID-19 hospitalized patients.
- Obesity may play a significant, age-independent role in the severity of COVID-19 illness.
Objective:
Obesity has been found to be a risk factor for hospitalization with coronavirus disease (COVID-19). This study investigated whether patients hospitalized with COVID-19 differed in BMI at older versus younger ages and whether trends were independent of diabetes and hypertension.
Methods:
A cross-sectional analysis of patients hospitalized with moderate to severe COVID-19 at Northwestern Memorial Hospital from March 19, 2020, until April 4, 2020, was performed. Patients hospitalized with COVID-19 above and below the age of 50 were compared as well as those hospitalized without COVID-19.
Results:
Patients younger than 50 years of age hospitalized with COVID-19 without diabetes or hypertension had mean BMI greater than those older than 50 years of age, with BMI 43.1 (95% CI: 34.5-51.7) versus 30.1 (95% CI: 27.7-32.5) (P = 0.02). Furthermore, BMI appeared to inversely correlate with increasing age among patients hospitalized with COVID-19. We did not detect the same difference or trend for patients hospitalized without COVID-19.
Conclusions:
Younger patients (age < 50 years) with COVID-19 had higher mean BMI than older patients with COVID-19, with and without diabetes and hypertension. This trend did not exist in patients without COVID-19 hospitalized during the same time period.
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