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Obesity increases the risk of SARS-CoV-2 infection by 34%
Last reviewed: 02.07.2025
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A new study published in the journal PNAS Nexus has found that being overweight not only worsens COVID-19 outcomes, but also increases the likelihood of contracting the virus. Researchers from Massachusetts General Hospital analyzed data from 687,813 patients, including 72,613 people exposed to SARS-CoV-2. The study covered the period from March 2020 to January 25, 2021, before widespread vaccination, to avoid potential confounding.
COVID-19 has become the most devastating pandemic in modern history, infecting more than 775 million people and killing more than 7 million. Much of the focus has been on factors that influence disease severity, such as older age, cardiovascular disease, type 2 diabetes, obesity, and hypertension. However, knowledge about the predispositions that influence susceptibility to SARS-CoV-2 infection after exposure remains limited.
The objective of this study was to estimate the incidence of SARS-CoV-2 transmission among people after suspected exposure to the virus and its association with potential risk factors, particularly overweight (obesity), hypertension, and age. Data were obtained from the Massachusetts General Hospital COVID-19 Data Mart database, which includes electronic medical records (EMRs) from across the United States. The study included patients in Massachusetts who were tested through January 25, 2021.
After excluding participants with incomplete data, 72,613 patients (58.8% women) were included in the analysis. Data analysis showed that the age group 40 to 64 years dominated the sample (39.7%), followed by patients over 64 years (30%), 20-39 years (24.7%), and 13-19 years (3.5%). Obesity was common in all age groups, with the highest percentage observed among middle-aged people (40-64 years). Overall, 33.7% (n = 24,438) of the study participants were obese.
The results of the logistic model showed that of the 72,613 people exposed to the virus, 18,447 people developed COVID-19. Obesity was found to be a significant predictor of COVID-19 infection with an odds ratio (OR) of 1.34, indicating a 34% higher likelihood of infection in obese people compared to non-obese people. This risk remained significant regardless of age, gender, and place of residence.
The study highlights that obesity is associated with a 34% higher likelihood of SARS-CoV-2 infection, making weight management programs an important preventive measure against the spread of COVID-19. The study authors note that despite the importance of obesity as a risk factor, interpretation of the results should take into account limitations such as the self-declared nature of exposure data and potential inaccuracies in electronic health records. Future studies may focus on examining common signaling pathways in obese individuals, which may lead to the identification of targets to reduce SARS-CoV-2 infectivity.
"Future mechanistic studies aimed at understanding common signaling pathways in obese individuals may lead to the identification of drug targets to reduce SARS-CoV-2 infectivity."