Does Age Impact the Obese Asthma Phenotype?: Longitudinal Asthma Control, Airway Function and Airflow Perception among Mild Persistent Asthmatics.
Chest. 2011 Jul 28 Lang JE, Hossain J, Dixon AE, Shade D, Wise RA, Peters SP, Lima JJ; for the American Lung Association-Asthma Clinical Research Centers*. 1Division of Pulmonology, Allergy & Immunology, Nemours Children's Clinic, Jacksonville, Florida;
BACKGROUND: The relationship between obesity and asthma remains inadequately defined. Studies conflict about how obesity affects asthma control and lung function. Additional focus on the effect of age as a modifier may make clearer the interaction between obesity and asthma phenotype. We sought to utilize a diverse and well-phenotyped cohort of asthmatic patients to determine how age impacts the relationship between obesity and spirometry, peak flow variability, airflow perception and asthma control.
METHODS: Characteristics of 490 patients with mild persistent asthma taken from 2794 study visits from a prospective trial studying strategies of step-down therapy were included in this post-hoc analysis. A longitudinal mixed-effect model was used to determine if age affects the relationship between obesity and asthma characteristics including spirometry, asthma control, airway pH and perception of airflow changes.
RESULTS: The effect of obesity on asthma outcomes changes with age and gender. Obese 6-11 year olds had the largest reduction in lung function, but reported relatively fewer asthma symptoms compared to similar non-obese asthmatics. Obese 12-17 year olds showed a trend toward greater airflow obstruction and asthma symptoms compared to non-obese asthmatics. Adults in general displayed few obesity-related alterations in asthma phenotype. Female gender among 12-17 and 18-44 year olds was associated with greater obesity-related asthma impairment.
CONCLUSIONS: Age is a significant effect modifier on the relationship between obesity and asthma phenotype. With increasing age, the influence of obesity on the asthma phenotype is generally reduced. The asthma phenotype may be most impacted by obesity among children and females.