Pediatric Diabetes 2010: 11: 493–497 doi: 10.1111/j.1399-5448.2010.00639.x All rights reserved © 2010 John Wiley & Sons A/S Pediatric Diabetes Original Article Low prevalence of glucose intolerance in racially mixed children with cystic fibrosis Alves C, Lima DS, Cardeal M, Santana A. Low prevalence of glucose intolerance in racially mixed children with cystic fibrosis. Pediatric Diabetes 2010: 11: 493 – 497. Objective: To evaluate glucose tolerance in racially mixed Brazilian youth with cystic fibrosis (CF). Methods: Cross-sectional study conducted between August and September 2007, at a reference service for CF, evaluating: glycated hemoglobin (HbA1c), blood glucose, and insulin levels, before and 2 h after a glucose overload. Results: There were 46 patients aged between 6 yr and 16 yr and 2 months (median: 9 yr and 10 months) of whom 64% were boys. Of these, 26% were Whites; 54.4% Mulattoes; and 19.6% Blacks. HbA1c was normal in all patients. Only one participant (12-yr old) had glucose intolerance. Insulin levels ranged from 1 to 23 μIU/mL (median: 4.5 μIU/mL) at baseline and from 3.2 to 192.1 μIU/mL (median: 11 μIU/mL) after a glucose overload. Insulin resistance evaluated by the HOMA index, stratified by sex and age, was present in three patients. The F508 mutation was present in only 4.3% of the sample, all of them being heterozygous. Conclusions: The low prevalence of carbohydrate intolerance in this population is probably a result of their young age. Another possibility is the low frequency of the F508 mutation. Although not conclusive, these data suggest that in addition to age, the genotype:phenotype ratio may influence the development of glucose intolerance in patients with CF. Cr ´ esio Alves a,b , Daniela S Lima a,b , Mauricio Cardeal c and Angelica Santana d a Federal University of Bahia, Salvador-Bahia, Brazil; b Pediatric Endocrinology Unit, Hospital Universitario Professor Edgard Santos, Federal University of Bahia, Salvador-Bahia, Brazil; c Biomedical Statistics Department, Federal University of Bahia, Salvador-Bahia, Brazil; and d Cystic Fibrosis Center, Hospital Oct ´ avio Mangabeira, Salvador-Bahia, Brazil Key words: cystic fibrosis – diabetes mellitus – glucose intolerance – race/ethnicity Corresponding author: Dr. Cr ´ esio Alves, Rua Plínio Moscoso, No. 222, Apto. 601, CEP: 40157-190, Salvador-Bahia, Brazil. Tel: +55 71 9178 4055; Fax: +55 71 3797 9990; e-mail: cresio.alves@uol.com.br Submitted 5 December 2009. Accepted for publication 21 December 2009 Introduction The increased longevity of patients with cystic fibrosis (CF) has lead to a higher incidence of glucose intolerance and diabetes mellitus associated with cystic fibrosis [cystic fibrosis-related diabetes (CFRD)] (1, 2). The main risk factors for CFRD are: adolescents and young adults, female gender, and exogenous pancreatic insufficiency (2–4). CFRD also appears to be more frequent in individuals homozygous for the F508 mutation (5). The insulopenia resulting from fibrosis and fatty infiltration of the pancreas is the main mechanism responsible for CFRD, although insulin resistance may also participate in this process (2, 6). As there is great variability in the prevalence of glucose intolerance and CFRD, the aim of this study was to evaluate the presence of glucose intolerance in youth with CF, from a racially mixed population. Materials and methods A cross-sectional study was conducted between August and September of 2007. Forty-six patients aged between 6 yr and 16 yr and 2 months, followed at a ref- erence service for CF in Salvador, Bahia, Brazil, were selected. Diagnosis of CF was made based on clinical criteria and by analyzing the sweat chloride concen- tration, in accordance with the technique described by Gibson & Cooke (7). The F508 mutation search 493