Only IgE and leptin showed significant differences between adolescents reporting presence and absence of allergy symptoms, respectively (P = 0.012 for IgE, and P = 0.017 for leptin) (Table 4); However, IgE was increased with allergy symptoms both, in boys and in girls, while leptin was only increased in girls with allergy symptoms but not in boys. Here, LEP is linked to allergic disease.