Background and objective: Increased BMI is a risk factor for asthma in children and may be related to adipokines. Adipokines affect insulin-stimulated glucose uptake in vitro but, to date there is little evidence for such a role in vivo. We explored relationships between obesity and allergic asthma in children.
Methods: Twenty-one allergic asthmatics (AA) and 10 non-allergic healthy controls, aged 6-17.9 years were studied. AA group included children with a positive mannitol challenge test, >25 ppb of exhaled nitric oxide and a positive skin prick test. BMI z-scores were calculated. Blood levels of insulin, glucose, leptin, resistin, tumour necrosis factor-alpha, IL-4, IL-5 and IL-6 were measured. Insulin resistance (IR) was estimated using the homeostasis model assessment (HOMA).
Results: There was no significant difference in BMI z-scores between AA and healthy controls (mean: 0.01 vs -0.10). However, significant differences were found in the blood levels of IL-6 (P = 0.05), IL-4 (P = 0.04), IL-5 (P = 0.01) and leptin (P = 0.02). IR was only found in the AA group (42.85%). Homeostasis model assessment insulin resistance (HOMA-IR) was significantly related to IL-6 (r = 0.44, P = 0.05) and tumour necrosis factor-alpha (r = -0.45, P = 0.05).
Conclusions: IR was observed in AA. Our findings are suggestive of a complex interaction between the inflammatory state and adiposity, allergy and asthma.