Associations of serum leptin with atopic asthma and allergic rhinitis in children

Background: There is growing evidence of positive correlations between asthma (AS) and obesity in adults and children. Leptin is an obesity gene product secreted by white adipose tissue; elevated serum levels are found in obese adults and children. Recently, leptin has also been found to be associated with allergic rhinitis (AR). However, the links between serum leptin, atopic AS, and AR remained undetermined. Because AS and AR share common allergic inflammatory mechanisms, our aim was to determine if there were any differences in serum leptin levels between asthmatic children and nonasthmatic children with AR. Methods: We studied 114 children (67 boys and 47 girls): 68 with mild intermittent-to-moderate persistent atopic AS (AS children) and 46 with mild-to-moderate persistent AR without AS (AR children; overall mean age, 8.51 years; range, 5-18 years). Body mass index (BMI), serum leptin, pulmonary function, and atopy parameters (serum IgE and eosinophil levels) were measured. Results: Compared with AR children, AS children had higher body weights (kg), body mass indices (kg/cm2), and serum leptin levels (ng/mL). Multiple linear regression analyses showed that serum leptin concentrations differed significantly for girls, being overweight and between disease groups (AS and AR children). Conclusion: Our results indicate that a higher serum leptin level has stronger association with mild-to-moderate persistent AS compared with AR. Hence, serum leptin may be a stronger predictor for childhood AS compared with AR. Among the asthmatic children, higher serum leptin levels also showed stronger associations with female gender and being overweight.