Effects of Age, Sex, Race/Ethnicity, and Allergy Status in Obesity-Related Pediatric Asthma

To determine the relationship between obesity and asthma incidence and assess the impact of age, gender, race/ethnicity and allergic status.

The study included 507 496 children ages 2–17 years. Children without a history of asthma prior to the pre-defined study start date were included and overweight or obese children were 1:1 matched with healthy weight children.

This was a large retrospective cohort study from 8 Pediatric institutions in the United States that were a part of PEDSNet (National Pediatric Clinical Network for Research), utilizing data through the Observational Health Data Sciences and Informatics (OHDSI) common data model from January 2009 to December 2015. Children were stratified 2–6 years, 7–11 years, and 12–17 years. Children with a BMI ≥95th percentile were categorized as obese. Asthma incidence was defined as ≥2 asthma encounters and ≥1 asthma prescription, and a subset included spirometry. Adjusted incident asthma rates and risk ratios were estimated by multivariate Poisson regression (adjusted for race, ethnicity and gender).

The risk of incident asthma was higher among obese children in all the age-groups as compared with children with healthy weights [age 2–7 years: RR 1.24 (95% CI 1.14–1.36); age 7–11 years: RR 1.45 (95% CI 1.29–1.64); and 12-17 years: RR 1.35 (95% CI 1.16–1.56)]. Children with no underlying allergic rhinitis had an increased risk of asthma across all age-groups [age 2–7 years: RR 1.25 (95% CI 1.15–1.37); age 7–11 years: RR 1.50 (95% CI 1.33–1.69); and 12–17 years: RR 1.40 (95% CI 1.21–1.63)], but this effect was not seen among children with an underlying allergic rhinitis diagnosis. Additionally, among younger children <12 years, obese females had a higher risk of asthma whereas among older children, the higher risk was seen among obese males.

Obesity is a preventable risk factor for asthma, especially among non-allergic children, and interventions to reduce obesity in the pediatric population need to be addressed as a public health priority.

This is the largest study to date looking at the impact of pediatric onset obesity on the development of asthma, despite limitations of a retrospective observational design. With the rising prevalence of obesity and the substantial impact of asthma on emergency department visits, hospitalizations and quality of life in children, there is a need to identify potentially modifiable factors for the development of asthma. This study identifies obesity as a risk factor across all age groups for the development of asthma but more importantly, highlights the differential effect among allergic and nonallergic children as well as the risk differences by sex and age. This points to the heterogeneity of asthma phenotypes in children that are likely a result of these different endophenotypes in children with underlying obesity and atopy, potentially raising questions about optimal treatment strategies in these different groups. Identification of a potentially modifiable risk factor provides opportunities to impact the lives of children, and further studies are needed to determine if early life interventions may prevent the subsequent development of asthma.