Obesity and Age Identified as Key Risk Factors for SARS-CoV-2 Transmission

Obesity significantly increases the risk of contracting COVID-19 upon exposure to the virus, with a 34% higher odds of testing positive compared to non-obese individuals, according to a study published in PNAS Nexus.

“The impaired rapidity and poor-quality immune response in patients with metabolic syndrome could contribute to weakened SARS-CoV-2 viral clearance,” explained Joan Matamalas, Department of Medicine, Cardiovascular Division, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School in Boston, MA, and coauthors. “We hypothesize that obese individuals have higher susceptibility to developing productive SARS-CoV-2 infection given comparable exposure to nonobese individuals,” they added.

The researchers used data from the Mass General Brigham (MGB) COVID-19 Data Mart, which included 72 613 individuals with suspected exposure to SARS-CoV-2 between March 2020 and January 2021. The study aimed to assess whether obesity serves as an intrinsic risk factor for SARS-CoV-2 infection, considering potential confounding factors such as age, sex, and pre-existing conditions like type 2 diabetes mellitus (T2DM) and hypertension.

Among the 72 613 participants, 58.8% were women and 41.2% were men, predominantly adults, with a wide age range. The racial composition included 72.4% White, 12.3% Hispanic, 6.7% Black, and 3.4% Asian individuals. The overall positivity rate for COVID-19 among those with suspected exposure was 25.4%, with rates being consistent across different age groups and between sexes.

Among the exposed individuals, 33.7% were obese, closely aligning with the prevalence of obesity in the United States. Obesity rates varied by race, with Black (46.3%) and Hispanic (43.8%) individuals showing higher prevalence compared with Asians (15.4%). Using logistic regression models adjusted for confounding factors, obesity was associated with a significantly increased risk of SARS-CoV-2 infection across all age groups and both sexes, with odds ratios ranging from 1.13 in older adults to 1.79 in adolescents aged 13 to 19 years.

Interestingly, while obesity remained a significant risk factor for COVID-19 positivity in individuals without diabetes, it was not statistically significant in those with T2DM. This finding suggests that obesity may have a more pronounced effect on COVID-19 susceptibility in non-diabetic populations.

“Our study identified obesity as an intrinsic risk factor for the spread of COVID-19 in individuals with comparable exposure risk,” concluded the study authors.

Reference

Matamalas JT, Chelvanambi S, Decano JL, et al. Obesity and age are transmission risk factors for SARS-CoV-2 infection among exposed individuals. PNAS Nexus. 2024;3(8). doi:10.1093/pnasnexus/pgae294