Obesity's effect on asthma extends to diagnostic criteria

Njira Lugogo, Cynthia L. Green, Noah Agada, Siyi Zhang, Susanne Meghdadpour, Run Zhou, Siyun Yang, Kevin J. Anstrom, Elliot Israel, Richard Martin, Robert F. Lemanske, Homer Boushey, Stephen C. Lazarus, Stephen I. Wasserman, Mario Castro, William Calhoun, Stephen P. Peters, Emily DiMango, Vernon Chinchilli, Susan KunselmanTonya S. King, Nikolina Icitovic, Monica Kraft

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Background: The use of inflammatory biomarkers to delineate the type of lung inflammation present in asthmatic subjects is increasingly common. However, the effect of obesity on these markers is unknown. Objectives: We aimed to determine the effect of obesity on conventional markers of inflammation in asthmatic subjects. Methods: We performed secondary analysis of data from 652 subjects previously enrolled in 2 Asthma Clinical Research Network trials. We performed linear correlations between biomarkers and logistic regression analysis to determine the predictive value of IgE levels, blood eosinophil counts, and fraction of exhaled nitric oxide values in relationship to sputum eosinophil counts (>2%), as well as to determine whether cut points existed that would maximize the sensitivity and specificity for predicting sputum eosinophilia in the 3 weight groups. Results: Overall, statistically significant but relatively weak correlations were observed among all 4 markers of inflammation. Within obese subjects, the only significant correlation found was between IgE levels and blood eosinophil counts (r = 0.33, P <.001); furthermore, all other correlations between inflammatory markers were approximately 0, including correlations with sputum eosinophil counts. In addition, the predictive value of each biomarker alone or in combination was poor in obese subjects. In fact, in obese subjects none of the biomarkers of inflammation significantly predicted the presence of high sputum eosinophil counts. Obese asthmatic subjects have lower cut points for IgE levels (268 IU), fraction of exhaled nitric oxide values (14.5 ppb), and blood eosinophil counts (96 cells/μL) than all other groups. Conclusions: In obese asthmatic subjects conventional biomarkers of inflammation are poorly predictive of eosinophilic airway inflammation. As such, biomarkers currently used to delineate eosinophilic inflammation in asthmatic subjects should be approached with caution in these subjects.

Original languageEnglish (US)
Pages (from-to)1096-1104
Number of pages9
JournalJournal of Allergy and Clinical Immunology
Volume141
Issue number3
DOIs
StatePublished - Mar 2018

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology

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