Does Obesity Increase Respiratory Tract Infections in Patients with Asthma?

Publication date: Available online 9 October 2018

Source: The Journal of Allergy and Clinical Immunology: In Practice

Author(s): Monica Tang, Robert J. Henderson, Janet T. Holbrook, Loretta G. Que, Anne M. Mathews, Robert A. Wise, Anne E. Dixon, Stephen P. Peters, Linda Rogers, Lewis J. Smith, W. Gerald Teague, Jason E. Lang

Abstract

Background

Since respiratory tract infections (RTIs) precede most exacerbations, better understanding of the risk factors of RTIs and RTI-associated exacerbations in patients with asthma is a pressing public health need. Obesity in patients with asthma is associated with worse asthma control and higher asthma-associated healthcare utilization but its effect on RTI risk is unknown.

Objective

We aimed to study the association of BMI classification on the risk of self-reported RTIs and related asthma morbidity among adults and children with asthma.

Methods

This post-hoc analysis of five large asthma trials involving 747 children and 1287 adults compared BMI classification, defined as lean, overweight and obese based on age-appropriate body mass index (BMI) and BMI-percentile conventions. The primary outcome was rate of visits with RTIs. Secondary asthma outcomes included upper respiratory infection (URI) severity, systemic steroid use, and healthcare contact.

Results

Children had 1.4 times the rate of RTI compared to adults (95% CI 1.27-1.56). In all participants, BMI classification did not affect the rate of visits with RTI. In children, BMI classification did not affect URI severity, all-cause asthma events or RTI-associated asthma events. However, in adults, higher BMI classification was associated with an increase in moderate/severe URI (p=0.02). Adults with higher BMI classification also had increased rates of all-cause and RTI-associated asthma exacerbations requiring systemic steroids and healthcare contact.

Conclusions

BMI classification was not associated with increased risk of RTIs in children or adults. In adults only, obesity was associated with increased URI severity and all-cause and RTI-associated asthma morbidity.