Overweight children report qualitatively distinct asthma symptoms: analysis of validated symptom measures

Abstract

Background: Past studies of asthma in overweight/obese children have been inconsistent. The reason overweight/obese children commonly report worse asthma control remains unclear.

Objective: To determine qualitative differences in symptoms between lean and overweight/obese children with early-onset, atopic asthma.

Methods: We conducted a cross-sectional analytic study of lean (20% to 65% body mass index) and overweight/obese (≥85% body mass index) 10- to 17-year-old children with persistent, early-onset asthma. Participants completed 2 to 3 visits to provide a complete history, qualitative and quantitative asthma symptom characterization, and lung function testing. We determined associations between weight status and symptoms using multivariable linear and logistic regression methods.

Results: Overweight/obese and lean asthmatic children displayed similar lung function. Despite lower fraction of exhaled nitric oxide (30.0 vs 62.6 ppb; P = .037) and reduced methacholine responsiveness (PC20FEV1 1.87 vs 0.45 mg/mL; P < .012), overweight/obese children reported more than thrice frequent rescue treatments (3.7 vs 1.1 treatments/wk; P = .0002) than did lean children. Weight status affected the child's primary symptom reported with loss of asthma control (Fisher exact test; P = .003); overweight/obese children more often reported shortness of breath (odds ratio = 11.8; 95% CI, 1.41-98.7) and less often reported cough (odds ratio = 0.26; 95% CI, 0.08-0.82). Gastroesophageal reflux scores were higher in overweight/obese children (9.6 vs 23.2; P = .003) and appear to mediate overweight/obesity-related asthma symptoms.

Conclusions: Overweight/obese children with early-onset asthma display poorer asthma control and a distinct pattern of symptoms. Greater shortness of breath and β-agonist use appears to be partially mediated via esophageal reflux symptoms. Overweight children with asthma may falsely attribute exertional dyspnea and esophageal reflux to asthma, leading to excess rescue medication use.

Keywords: Asthma; breathlessness; children; dyspnea; esophageal reflux; obesity; overweight; shortness of breath.

FIG. 1

Controller and rescue treatment burden in normal and overweight/obese children with asthma. Black bars represent the median National Asthma Education and Prevention Program controller step prescribed by the treating asthma physician at the time of study enrollment. The median (interquartile range) for normal weight and overweight/obese children was 3 (2, 4) and 3 (3, 4), respectively (Wilcoxon test; P = .986). Gray bars represent the number of rescue treatments required (excluding exercise pretreatment) per week over the month before enrollment. The mean (SE) number of rescue treatments needed to manage asthma symptoms for normal weight and overweight/obese children was 1.1 (0.3) and 3.7 (0.6), respectively; #P = .0002, Student t test, for normal vs overweight/obese.