Effect of tobacco exposure on inhaled corticosteroid response in minority children with asthma
Samedy L, Oh S, Davis A, Serebrisky D, Brigino-Buenaventura E, Lurmann F, Ford J, Rodriguez-Santana JR, Meade K, Borrell LN, LeNoir MA, Avila PC, Kumar R, Chapela R, Sen S, Rodriguez W, Thyne S, Siebold M, Williams K, and Burchard EG. Effect of tobacco exposure on inhaled corticosteroid response in minority children with asthma. Am J Respir Crit Care Med 2018; 197.
Am J Respir Crit Care Med
Inhaled corticosteroid (ICS) treatment is the cornerstone for achieving asthma control. There is considerable racial/ethnic variability in ICS response. Racial/ethnic minorities experience ICS resistance at a higher level than whites. The pathogenetic mechanisms of racial/ethnic differences in ICS resistance have been understudied and are poorly understood. Active smoking induces neutrophilic airway inflammation and is associated with resistance to ICS therapy, potentiating severe, steroid-resistant asthma. However, there is little direct information about the effect of second hand smoke (SHS) exposure on ICS response. Elucidating clinical effects and relative contribution of SHS on ICS drug response is necessary given that minority children have the highest asthma prevalence and mortality, the lowest drug response to asthma therapies, and greater prevalence of SHS exposure. To characterize the association between SHS exposure and ICS resistance, by analysis of asthma-related health outcomes in minority children with asthma from 3 different racial/ethnic populations. We performed a case-only analysis of 685 Mexican American (MX), 1152 Puerto Rican (PR), and 871 African American children (AA) with physician-diagnosed asthma (N=2,708). SHS exposure data were collected from parents using an ATS standardized questionnaire and serum cotinine among a subset. Indicators of ICS efficacy included spirometric measures of lung function, asthma symptoms (wheezing, shortness of breath, coughing, nocturnal wakening) and severe asthma exacerbations (hospitalization, oral steroid use). Each indicator was tested for association through analysis of covariance, controlling for potential confounding factors. Overall, 23.4% of children lived with at least one smoker (AA > PR > MX). In children with asthma, FEF25-75 is a more sensitive indicator of airway obstruction. Independent of ICS therapy, our results demonstrate that PR patients have a significantly lower FEF25-75 (forced expiratory flow between 25 and 75 seconds) (p=0.000) compared to their AA and MX counterparts. However, after stratification for SHS and ICS use, we observed a significantly lower drug response to ICS use in FEF25-75 levels in AA compared to PR or MX children with asthma. This observation is consistent with previous reports of steroid resistance in African American children with asthma. Tobacco smoke exposure impairs the efficacy of ICS treatment in children with asthma. This observation may contribute to the excess asthma morbidity and mortality children. These findings have important clinical and public health implications for the management of patients with asthma exposed to tobacco smoke.