Class III Obesity as a Risk Factor for Persistent Asthma.

Background: The burden of asthma remains steady with no decline observed in the past few decades. Obesity prevalence has been steadily increasing with a rate of 41.9% in the United States between 2017-2020. Obesity is an inflammatory chronic condition that may partially contribute to the burden and severity of asthma. This study aimed to examine whether the association between obesity and asthma varies with the categories of obesity (class I, II, and III) and persistent asthma (mild, moderate, and severe asthma). We hypothesized that subjects with elevated body mass index (BMI) are more likely to be diagnosed with persistent asthma than subjects without obesity with asthma.

Methods: As a retrospective and cross-sectional study, this study used a total of 1,977 records of subjects with asthma (age ≥ 19 y) hospitalized in Nevada between 2016-2021. BMI and persistent asthma were evaluated as the main exposure and outcome of interest. Logistic regression was used to estimate the magnitude of the association between obesity and persistent asthma.

Results: Among the selected subject records, subjects with obesity were more likely to be diagnosed with persistent asthma compared to subjects without obesity (odds ratio 1.50 [CI 1.10-2.05]). Subgroup analyses revealed that subjects with class III obesity (BMI ≥ 40) were more likely than subjects without obesity to be diagnosed with mild persistent asthma (odds ratio 2.21 [CI 1.18-4.16]) and severe persistent asthma (odds ratio 1.74 [CI 1.12-2.70]).

Conclusions: Obesity was identified as a risk factor for persistent asthma, particularly class III obesity. This in turn increases the potential for greater health care utilization and economic burden. Public health and clinical interventions are necessary among those with comorbid asthma and obesity.