Comorbid Obesity and Depressive Symptoms in Childhood Asthma: A Harmful Synergy.

BACKGROUND:Overweight/obesity (OV/OB) and depression have each been separately associated with worsened childhood asthma severity and control. Pathways by which these factors may jointly affect childhood asthma have not been elucidated. OBJECTIVE:To examine the interrelationship of OV/OB and depressive symptoms with childhood asthma and explore associated psychobiologic pathways. The present study investigated whether comorbid OV/OB and depressive symptoms are associated with impaired baseline lung function and increased airway resistance during emotional stress, and to assess whether such effects may be mediated by autonomic nervous system (ANS) dysregulation, specifically through predominance of vagal over sympathetic reactivity (vagal bias). METHODS:A total of 250 children with asthma, aged 7 to 17, were assessed for OV/OB using body mass index, depressive symptoms using the Children's Depression Inventory (CDI), and asthma severity using National Asthma Education and Prevention Program Expert Panel Report 3 criteria. Baseline pulmonary function (forced expiratory volume in 1 second [FEV1]) was assessed. The film "E.T. the Extra-Terrestrial" was used in a laboratory paradigm to evoke emotional stress/arousal. Airway resistance (Rint) was measured before and after the film to determine changes in airway function. ANS reactivity was assessed by measuring parasympathetic/vagal and sympathetic reactivity throughout the film. RESULTS:In OV/OB children with asthma, depressive symptoms predicted lower baseline FEV1 (β = -0.67, standard error [SE] = 0.24, P = .008), CDI predicted vagal bias under emotion stress/arousal (β = 0.27, SE = 0.09, P = .009), and vagal bias predicted increased Rint (β = 3.55, SE = 1.54, P = .023). CONCLUSION:This study is the first to link OV/OB and depressive symptoms in their relationship to childhood asthma. In OV/OB children with asthma, depression may potentiate airway compromise, mediated by vagal bias. Use of antidepressant and anticholinergic therapies should be studied in this subgroup of patients.