title: Hypoglycemia is common in children with cystic fibrosis and seen predominantly in females.
abstract: OBJECTIVE
  To determine the prevalence of hypoglycemia in children and adolescents with cystic fibrosis (CF) in 2-hour oral glucose tolerance test (OGTT) and continuous glucose monitoring (CGM) under free-living conditions.
  
  
  METHODS
  Height, weight, body mass index (BMI), hemoglobin A1c (HbA1c), and Forced expiratory volume (FEV1%) were measured in children with CF (aged 5-18 years). Following OGTT, CGM was installed for 3 days. The total hypoglycemic and hyperglycemic time (%) during 3 days was measured. Subjects were categorized according to hypoglycemic time <3% (hypo -) and ≥3% (hypo +). Each category was further divided according to hyperglycemic time <3% (hyper -) or ≥3% (hyper +).
  
  
  RESULTS
  OGTT and CGM were sequentially performed in 45 CF patients. The frequency of hypoglycemia in OGTT and hypoglycemic time ≧3% of CGM were 13.3% and 27.5%, respectively. After 5 cystic fibrosis-related diabetes (CFRD) subjects were excluded, the number of subjects in each subgroup was 17 (hypo-/hyper-), 12 (hypo-/hyper+), 6 (hypo+/hyper-), and 5 (hypo+/hyper+). Significantly higher insulin at 120 minutes was observed in OGTT in (hypo+/hyper-), as compared with subgroup (hypo-/hyper-) (P = .018). Total insulin levels were also significantly higher in (hypo+/hyper-), than (hypo-/hyper-), but were similar to those in the healthy control group (P = .049 and P = .076, respectively). There was a female predominance in hypoglycemic subjects both in OGTT and subgroup (hypo+/hyper-) in the CGM group (P = .033 and P = .033, respectively). FEV1 was significantly lower in hypo + group as a whole, and (hypo+/hyper+) subgroup than in (hypo-/hyper-), (P = .044 and P = .042, respectively); the difference was independent of body mass index-standard deviation score (BMI-SDS) (P = .15 and P = .12, respectively).
  
  
  CONCLUSIONS
  The frequency of hypoglycemia in children with CF was higher in CGM than that in OGTT. Insulin secretion was delayed and total insulin levels increased in the hypoglycemic patients. Glucose instability/hypoglycemia is associated with poorer lung function in patients with CF, independent of nutritional status.
authors.affiliation: Department of Pediatric Endocrinology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Belma
authors.initials: B
authors.lastname: Haliloglu
authors.affiliation: Department of Pediatric Pulmonology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Gokdemir
authors.affiliation: Department of Pediatric Endocrinology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Atay
authors.affiliation: Department of Pediatric Endocrinology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Saygin
authors.initials: S
authors.lastname: Abali
authors.affiliation: Department of Pediatric Endocrinology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Tulay
authors.initials: T
authors.lastname: Guran
authors.affiliation: Department of Pediatric Pulmonology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Fazilet
authors.initials: F
authors.lastname: Karakoc
authors.affiliation: Department of Pediatric Pulmonology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Refika
authors.initials: R
authors.lastname: Ersu
authors.affiliation: Department of Pediatric Pulmonology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Bulent
authors.initials: B
authors.lastname: Karadag
authors.affiliation: Department of Pediatric Endocrinology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Serap
authors.initials: S
authors.lastname: Turan
authors.affiliation: Department of Pediatric Endocrinology, Marmara University, School of Medicine, Istanbul, Turkey.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Bereket
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D003550:Cystic Fibrosis / Q000097:blood / Q000453:epidemiology* / Q000208:ethnology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000503:physiopathology; D007003:Hypoglycemia / Q000097:blood / Q000453:epidemiology* / Q000208:ethnology / Q000503:physiopathology; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D000078790:Insulin Secretion; D008168:Lung / Q000503:physiopathology*; D008297:Male; D018670:Monitoring, Ambulatory; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D014421:Turkey / Q000453:epidemiology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human
keywords: 
  CGM
  ; 
  FEV1
  ; 
  OGTT
  ; cystic fibrosis; hypoglycemia