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Impact of obesity on COVID-19 diagnosis and outcomes

Last updated 20-05-2021

People with COVID-19 who are living with obesity are more likely to experience more severe disease outcomes and to die. Obesity may also be a risk factor for COVID-19 diagnosis. The biological mechanisms by which obesity is associated with COVID-19 infection and outcomes are currently under investigation.

Key Evidence


People who died from COVID-19 were about 1.5 times more likely to be obese than people who survived this disease


People living with obesity may have a higher chance of being diagnosed with COVID-19


Chronic conditions caused by obesity, such as cardiovascular disease and diabetes, may be causing the increased mortality from COVID-19 in people with obesity

COVID-19 is caused by SARS-CoV-2 viral infection of the respiratory tract. Whilst most people recover from the disease, approximately 3.6% of people die from COVID-19.1 Mortality from COVID-19 is a greater risk for people with certain risk factors such as being male, black ethnicity, older age, specific chronic health conditions or obesity.234567

Since this virus infects the respiratory tract, it’s somewhat surprising that being a smoker or having chronic respiratory conditions, such as chronic obstructive pulmonary disease, are not particularly strong risk factors for COVID-19 infection or outcomes.78

Many studies have concluded that obesity is a risk factor for COVID-19 disease severity.691011121314

Numerous meta-analyses have combined data from multiple studies, consistently finding that people who are obese have a higher risk of:

  • hospitalisation24 5 6
  • intensive care use2356
  • mechanical ventilation356 and
  • mortality23456

from COVID-19, compared to people in the healthy weight range. People who died from COVID-19 were about 1.5 times more likely to be obese, with BMI over 30 kg/m2.2 3 These associations remained when demographic factors such as age, sex and socioeconomic status were taken into account.

A large prospective study that closely examined the interactions between different clinical risk factors for COVID-19 mortality showed that having cardiovascular disease, hypertension, diabetes, autoimmune disease or oral steroid use were independently associated with COVID-19 mortality.7 Obesity was not independently associated with mortality in this study. These results indicate that the increased COVID-19 mortality risk from being obese may be due to conditions caused by obesity, such as cardiovascular disease and diabetes.7

People who are living with obesity may be more likely to be diagnosed with COVID-19 compared to people in a healthy weight range.21516 Prospective studies from the United Kingdom used pre-existing data from primary care databases and biobanks to show that people with obesity were more likely to test positive for COVID-19.1516 These studies have predicted a 1.41 to 1.55 fold increase in the odds of testing positive for COVID-19 for people with obesity compared to those in the healthy weight range. The biological mechanisms underlying this observation are currently under investigation.

Statements by the World Health Organization and the World Obesity Federation support the association of obesity with poor outcomes from COVID-19. The World Health Organisation has stated that:17

“The latest scientific evidence, based on multiple studies, shows that patients with obesity (including young adults) hospitalized with COVID-19 experienced substantially higher rates of severe outcomes, such as requiring intensive care treatment, mechanical ventilation and death.”

The World Obesity Federation has stated that:18

“Systematic reviews and meta-analyses overwhelmingly show that obesity is associated both with a higher risk for intensive care unit (ICU) admission and poorer outcomes for COVID-19.”


1. Johns Hopkins University. COVID-19 dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU). Baltimore, MA: JHU, 2021. Available from:
2. Popkin BM, Du S, Green WD, Beck MA, Algaith T, et al. Individuals with obesity and COVID-19: A global perspective on the epidemiology and biological relationships. Obesity Reviews, 2020; 21(11):e13128. Available from:
3. Huang Y, Lu Y, Huang YM, Wang M, Ling W, et al. Obesity in patients with COVID-19: a systematic review and meta-analysis. Metabolism, 2020; 113:154378. Available from:
4. de Siqueira JVV, Almeida LG, Zica BO, Brum IB, Barceló A, et al. Impact of obesity on hospitalizations and mortality, due to COVID-19: A systematic review. Obesity Research & Clinical Practice, 2020; 14(5):398-403. Available from:
5. Malik P, Patel U, Patel K, Martin M, Shah C, et al. Obesity a predictor of outcomes of COVID-19 hospitalized patients: A systematic review and meta-analysis. Journal of Medical Virology, 2021; 93(2):1188-93. Available from:
6. Soeroto AY, Soetedjo NN, Purwiga A, Santoso P, Kulsum ID, et al. Effect of increased BMI and obesity on the outcome of COVID-19 adult patients: A systematic review and meta-analysis. Diabetology & Metabolic Syndrome, 2020; 14(6):1897-904. Available from:
7. Elliott J, Bodinier B, Whitaker M, Delpierre C, Vermeulen R, et al. COVID-19 mortality in the UK Biobank cohort: revisiting and evaluating risk factors. European Journal of Epidemiology, 2021:1-11. Available from:
8. Simons D, Shahab L, Brown J, and Perski O. The association of smoking status with SARS-CoV-2 infection, hospitalisation and mortality from COVID-19: A living rapid evidence review with Bayesian meta-analyses (version 11). Qeios, 2021. Available from:
9. Finer N, Garnett SP, and Bruun JM. COVID-19 and obesity. Clinical Obesity, 2020; 10(3):e12365. Available from:
10. Hamer M, Gale CR, Kivimäki M, and Batty GD. Overweight, obesity, and risk of hospitalization for COVID-19: A community-based cohort study of adults in the United Kingdom. Proceedings of the National Academy of Sciences of the United States of America, 2020; 117(35):21011-3. Available from:
11. Williamson EJ, Walker AJ, Bhaskaran K, Bacon S, Bates C, et al. Factors associated with COVID-19-related death using OpenSAFELY. Nature, 2020; 584(7821):430-6. Available from:
12. Yang J, Hu J, and Zhu C. Obesity aggravates COVID-19: A systematic review and meta-analysis. Journal of Medical Virology, 2021; 93(1):257-61. Available from:
13. Goyal P, Choi JJ, Pinheiro LC, Schenck EJ, Chen R, et al. Clinical Characteristics of Covid-19 in New York City. New England Journal of Medicine, 2020; 382(24):2372-4. Available from:
14. Richardson S, Hirsch JS, Narasimhan M, Crawford JM, McGinn T, et al. Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area. JAMA, 2020; 323(20):2052-9. Available from:
15. de Lusignan S, Dorward J, Correa A, Jones N, Akinyemi O, et al. Risk factors for SARS-CoV-2 among patients in the Oxford Royal College of General Practitioners Research and Surveillance Centre primary care network: a cross-sectional study. The Lancet Infectious Diseases, 2020; 20(9):1034-42. Available from:
16. Yates T, Razieh C, Zaccardi F, Davies MJ, and Khunti K. Obesity and risk of COVID-19: analysis of UK biobank. Primary Care Diabetes, 2020; 14(5):566-7. Available from:
17. World Health Organization. Obesity significantly increases chances of severe outcomes for COVID-19 patients. 2020. Available from:
18. World Obesity Federation. Obesity and COVID-19 policy statement. 2020. Available from: