Study results show link between obesity and risk of COVID-19, a long-term disease

Analysis of more than 30,000 UK adults from 9 prospective cohort studies found that high pre-pandemic BMI was associated with infection.

Having a high body mass index (BMI) instead of high blood sugar levels is associated with an increased risk of COVID-19 infection, as well as long-term COVID-19 infection, according to results of a study published at the European Association for the Study of Diabetes- Annual meeting in Stockholm, Sweden.

“Early on in the pandemic, research identified diabetes and obesity as risk factors for serious illness from COVID-19, and we know so many [individuals] People living with type 2 diabetes are also overweight. Our early results support the idea that obesity-related mechanisms may be responsible for the excessive risks of COVID-19 related to diabetes and not to high blood sugar per se,” Anika Knüppel, PhD, of MRC’s Lifelong Health Unit and Aging at University College London in the United Kingdom, said in a statement.

Other research has shown that people with diabetes and obesity are more likely to get sick and die from COVID-19 infection, but not more likely to get it.

Investigators in the latest study sought to determine the associations between a number of clinical characteristics measured prior to the pandemic, including BMI, HbA1c, drug-based or self-reported diabetes, self-reported COVID-19 infection, and long COVID and waist-to-waist-hip ratios.

Analyzes from 9 ongoing UK cohort studies included the most recent measurements taken between 2002 and 2019 such as HbA1c, height, hip and waist circumference and weight. Investigators also collected information from health and lifestyle questionnaires.

All subjects had data on previous measurements and completed at least 1 questionnaire during the COVID-1 pandemic from May 2020 to September 2021, which included questions about the illness and questions about the duration of ongoing associated symptoms.

Individuals reported having COVID-19 based on a positive test or strong suspicion, and long COVID was defined as symptoms lasting more than 4 weeks after infection. Long COVID symptoms were compared to those reported for less than 4 weeks.

Investigators corrected for education, ethnicity, income, gender, and smoking at the time of measurement as necessary.

Between May 2020 and September 2021, 5806 people reported having had COVID-19 and 584 people reported having had long-term illness from COVID.

The results of the data analysis, which included 31,252 people in 9 studies, showed that higher BMI was associated with a higher likelihood of COVID-19 infection, with a 7% higher risk for every 5 kg/m2 increase in BMI.

Additionally, people who were obese or overweight were 16% and 10% more likely to contract COVID-19 than people who were not obese or overweight, respectively.

Investigators saw comparable results for those with long COVID, including 423 people from 6 studies. The risk was 20% higher for every 5 kg/m2 increase in BMI. People who were obese or overweight were 36% and 20% more likely to have long COVID, respectively.

Investigators reported that both COVID-19 infection and long COVID-related BMI categories were not all statistically significant.

Studies that focused on average HbA1c and diabetes had no association with COVID-19 or long COVID, they said.

More research is needed to explore the mechanisms of these associations and reduce the risk associated with high BMI, the researchers said.


Obesity, not high blood sugar, associated with increased risk of COVID-19 infection and long COVID. press release. EurekAlert. September 16, 2022. Accessed September 22, 2022.

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