Association between COVID-19 severity, obesity stronger for adults younger than 70 years
Obesity was associated with an increased risk for hospitalization for individuals with COVID-19 in Tuscany, Italy, with the association more prominent in adults younger than 70 years, according to study data.
“The present data confirm that obesity is associated with an increased risk of hospitalization in patients with COVID-19, even adjusting for potential confounders, consistently with previously reported results,” Edoardo Mannucci, MD, associate professor of endocrinology at the University of Florence, Italy, and colleagues wrote in a study published in Nutrition, Metabolism, & Cardiovascular Diseases. “Interestingly, the association of obesity with hospitalization was greater in younger patients. It can be speculated that other known risk factors were more frequent in older individuals, thus providing a greater contribution to disease severity.”
Researchers conducted an observational study of the Tuscany section of the Istituto Superiore di Sanità’s COVID-19 database. COVID-19 cases registered in the database through April 30 were included. Data on sex, age, comorbidities and other concurrent conditions were included.
There were 4,481 individuals included in the study (50.5% men). Of the study population, 53.1% were older than 60 years, 36.9% were older than 70 years, and 42.6% were admitted to the hospital.
In unadjusted data, obesity was associated with an elevated risk for hospitalization (RR = 1.74; 95% CI, 1.56-1.97). Obesity remained associated with a higher hospitalization risk after adjusting for age and sex (adjusted OR = 2.99; 95% CI, 2.04-4.37) and in a model where deceased individuals not previously hospitalized were excluded (aOR = 2.99; 95% CI, 2.04-4.39). Obesity was also associated with a higher mortality rate in those with obesity vs. individuals without obesity (18.2% vs. 8.3%; P < .001)
In an alternate model where the interaction between obesity and age was added, both obesity (OR = 1.82; 95% CI, 1.07-3.1) and age younger than 70 years (OR = 3.1; 95% CI, 1.5-6.43) were associated with an increased risk for COVID-19 hospitalization. There was no association found between sex and hospitalization risk in another model factoring obesity and sex.
“Several mechanisms could contribute to the increased severity of COVID-19 in obese patients,” the researchers wrote. “Excess weight is a risk factor for several conditions (diabetes, cardiovascular disease, respiratory disease), which have been associated with poorer COVID-19 outcomes. However, the association of obesity with hospitalization retains statistical significance even after adjusting for those conditions, suggesting different mechanisms.”
The researchers noted that obstructive sleep apnea was not available as a possible confounder in the data and could contribute to the increased risk for severe COVID-19. Other possible mechanisms the researchers listed included changes in lung mechanics, low-grade systemic inflammation with interleukin-6 production, reduced expression of toll-like receptor 7, hyperexpression of angiotensin-converting enzyme 2 and systemic endothelial dysfunction.