Childhood obesity and risk of allergy or asthma.

The simultaneous increment in the prevalence of obesity and allergic diseases suggests a possible link between them. This review focuses on the consequences of obesity on allergic diseases, especially asthma in children and adolescents, and evaluates the available evidence on the possible mechanisms. Obesity is related more strongly to nonatopic than atopic asthma, suggesting non-eosinophilic inflammation and Th1 polarization. Among other allergic diseases, the association is more consistent with eczema compared to allergic rhinitis/rhinoconjunctivitis. The mechanisms of asthma in obese individuals could involve mechanical effects of obesity on lung function, adipokines-mediated inflammation, shared factors (diet, genetics, sedentary lifestyle) and comorbidities.