Being Overweight Increases the Risk of COVID-19

Being Overweight Increases the Risk of COVID-19

by Dr. Trupti Shirole on Sep 20 2022 11:54 AM
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  • Diabetes and obesity are risk factors for becoming severely ill with COVID-19
  • A higher chance of contracting COVID-19 and long COVID-19 was linked to a high pre-pandemic BMI.
According to a meta-analysis of more than 30,000 UK individuals from nine sizable prospective cohort studies, having a high body mass index (BMI) is more closely linked to an increased risk of COVID-19 infection and long COVID than having high blood sugar levels.

Risk Factors for COVID-19

“Early in the pandemic, research identified diabetes and obesity as risk factors for becoming severely ill with COVID-19. And we know that many people with type 2 diabetes have excess weight. Our early findings support that obesity-related mechanisms may be responsible for the excess risks of COVID-19 associated with diabetes, rather than high blood sugar per se,” says Dr Knuppel.

Previous studies revealed that while patients with diabetes and obesity are not more likely to get COVID-19, they are more likely to experience severe illness and eventually pass away. Uncertainty surrounds the underlying mechanisms and their contribution to the long-lasting post-COVID-19 symptoms.

In order to learn more, researchers looked for correlations between self-reported COVID-19 infection and long COVID in nine ongoing UK cohort studies and a variety of clinical characteristics measured prior to the pandemic, including HbA1c (average blood sugar level), self-reported or medication-based diabetes, body mass index (BMI) and waist-to-hip ratio (WHR).

The analyses included data from questionnaires on health and lifestyle, the most recent measurements of HbA1c, weight, height, waist and hip circumference from each study (taken between 2002 and 2019).

During the COVID-19 pandemic (May 2020 to September 2021), all eligible participants (maximum 31,252, aged 19 to 75, 57% female) completed at least one questionnaire covering questions on COVID-19 and, when possible, questions on the period of persistent COVID-19-related symptoms.

Participants with a positive test or a strong suspicion of having COVID-19 reported having it. When compared with individuals reporting symptoms for less than four weeks after infection, long COVID was defined as symptoms that persisted or had an impact on functioning for more than four weeks post-infection.

At the time of measurement, relationships were adjusted for sex, smoking, ethnicity, income, and education.

5,806 participants reported experiencing COVID-19 between May 2020 and September 2021, and 584 said they had protracted COVID (about 7% of COVID-19 instances with information on symptoms length).


What is a Bigger Risk for COVID-19: Obesity or Diabetes?

Higher BMI was associated with increased odds of COVID-19 infection, with the risk increasing by 7% for every 5 kg/m2 increase in BMI, according to an analysis of data from 31,252 participants in nine trials. The probabilities of contracting COVID-19 infection were 10% and 16% higher in overweight (BMI 25-29.9 kg/m2) and obese people (30 kg/m2 or more), respectively than in people with a healthy weight (less than 25 kg/m2).

Similar findings were seen for extended COVID (4,243 participants, six studies), with the risk increasing by 20% for every kilogram of BMI over the baseline. Obesity and overweight individuals exhibited risks of protracted COVID that were correspondingly 20% and 36% higher. However, not all relationships between COVID infection and long-term COVID and BMI categories were statistically significant.

Inconclusive results came from analyses looking into the association with WHR.

Notably, research concentrating on diabetes and average blood sugar level (HbA1c) (15,795 participants and 1,917 for long COVID) found no correlation between COVID-19 or long-COVID.

The authors emphasize the need for additional study to understand the processes underlying these relationships and to lessen the excess risk of high BMI.

“Our early findings suggest a link of adiposity with COVID-19 infection and long COVID-19 even after considering socio-demographic factors and smoking. We need to further explore what makes people overweight and obese at risk of worse outcomes and how this relates to severe cases”, says Knuppel.

The study was observational, the authors acknowledge, and they cannot prove that having a higher BMI increases the risk of contracting COVID-19. They also cannot completely rule out the possibility that other unmeasured factors (such as underlying conditions) or missing data may have an impact on the findings. Additionally, they point out that some of the included studies may use clinical data that are no longer valid because COVID-19 was based on suspicion rather than a positive test. Finally, they point out that study participants were in better condition than the overall population, which would constrain the generalizations.