Association between occupational exposure to irritants and adult asthma profiles identified by clustering

Abstract

The biological mechanisms involved in asthma caused by occupational irritants remain poorly understood. Occupational exposure to irritants may be associated to a specific asthma endotype. We aimed to study the associations between occupational exposure to irritants and asthma profiles identified by a cluster analysis integrating clinical characteristics and biomarkers related to oxidative stress and inflammation. We analyzed data from 997 adults from the second phase of the EGEA study (mean age: 45 years, 46% men). Exposure to irritants at the current job was assessed by a new asthma-specific job exposure matrix (http://oasjem.vjf.inserm.fr/), with 3 levels of exposure (no/medium/high). Logistic regression models adjusted for age, sex and smoking were used to study the associations between occupational exposure to irritants and each profile (P). Predominant characteristics of the profiles were: P1 asymptomatic (n=463); P2 respiratory symptoms without asthma (n=167); P3 adult-onset asthma, poor lung function, respiratory symptoms, highest oxidative stress-related biomarker and neutrophil levels (n=50); P4 paucigranulocytic asthma, normal lung function (n=203); P5 childhood-onset asthma, highest IgE level (n=114). In P1, 9% had high exposure to irritants, 10% in P2, 22% in P3, 8% in P4 and 12% in P5. High exposure to irritants was associated with P3 (vs. P1, Odds Ratio (OR) [95%CI]=2.8 [1.2-6.5]). Occupational exposure to irritants was not associated with other profiles (OR range:0.9-1.3). Results suggest that occupational exposure to irritants was related to an asthma endotype characterized by poor lung function, respiratory symptoms, oxidative stress and neutrophilic inflammation.