ORIGINAL ARTICLE Asthma and insulin resistance in children MANDANA ARSHI, 1 JOHN CARDINAL, 2 REBECCA J. HILL, 1 PETER S.W. DAVIES 1 AND CLAIRE WAINWRIGHT 3,4 1 The University of Queensland, Children’s Nutrition Research Centre, Discipline, Royal Children’s Hospital, 2 Department of Chemical Pathology, Queensland Health Pathology Services, 3 Queensland Children’s Respiratory Centre, Royal Children’s Hospital, and 4 The University of Queensland, Discipline of Paediatrics and Child Health, Royal Children’s Hospital, Brisbane, Queensland, Australia ABSTRACT 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 evi- dence 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, resis- tin, tumour necrosis factor-a, 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-a (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. Key words: adipokine, asthma, body mass index, insulin resistance, obesity. INTRODUCTION The increase in overweight/obesity and asthma is an emerging public health concern. Obese individuals have an increased risk for the development of insulin resistance and diabetes. 1–4 Recently, a large body of epidemiologic data have linked obesity with the development of asthma 5 and obesity is a risk factor for asthma. 6,7 Nevertheless, little is known about the bio- logical mechanisms that relate obesity and insulin resistance to asthma. Fat tissue is no longer considered simply a storage tissue for energy. Fat may induce systemic low-grade inflammation in obese and overweight individuals by recruiting macrophages and production and secre- tion of a wide range of inflammatory molecules known as adipokines that include leptin, resistin, plasminogen activator inhibitor-1 (PAI-1), tumour necrosis factor-a (TNF-a) and IL-6. 8–10 Adipokines have local effects on the physiology of adipose tis- sue, 11 but may also have systemic effects on other organs. 12,13 These findings have lead to excessive fat tissue accumulation being implicated as a risk factor for the development of insulin resistance, cardiovas- cular diseases 14,15 and diabetes. 15–17 It is well known that increased BMI is associated with insulin resistance. 2,3,18–20 Recently, an epidemio- logical, population-based study on the relationship of insulin resistance and asthma found that insulin resistance was associated with increased risk of aeroallergen sensitization and allergic asthma in adults. 21 A recent 5-year prospective study in adults has reported that patients with insulin resistant are more prone to the development of wheezing and asthma-like symptoms than their non-insulin resis- tance counterpart and that the effect of insulin Correspondence: Mandana Arshi, Children’s Nutrition Research Centre, Discipline of Paediatrics and Child Health, Royal Children’s Hospital, Brisbane, Qld 4029, Australia. Email: m.arshi@uq.edu.au Received 11 June 2009; invited to revise 13 August 2009; revised 2 January 2010; accepted 1 February 2010 (Associate Editor: Darryl Knight). SUMMARY AT A GLANCE Although it has been shown that obesity and asthma are related, little is known about the linking mechanism. This study explores the under- lying mechanism in this relationship by investigat- ing insulin resistance (IR), a clinical sequel to obesity, and the blood levels of adiposity-related cytokines and chemokines (adipokines) in Austra- lian children with persistence allergic asthma. © 2010 The Authors Journal compilation © 2010 Asian Pacific Society of Respirology Respirology (2010) 15, 779–784 doi: 10.1111/j.1440-1843.2010.01767.x