title: Different cutoff values of methacholine bronchial provocation test depending on age in children with asthma.
abstract: BACKGROUND
  Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma. Although several factors such as airway caliber can affect BHR, no study has established age-dependent cutoff values of BHR to methacholine for the diagnosis of asthma in children. We investigated the cutoff values of the methacholine challenge test (MCT) in the diagnosis of asthma according to age.
  
  
  METHODS
  A total of 2383 individuals aged from 6 to 15 years old were included in this study. MCTs using the five-breath technique were performed in 350 children with suspected asthma based on symptoms by pediatric allergists and in 2033 healthy children from a general population-based cohort. We determined the provocative concentration of methacholine producing a 20% decrease in forced expiratory volume in 1 second from baseline (PC20). A modified Korean version of the International Study of Asthma and Allergies in Childhood questionnaire was used to distinguish asthmatics and healthy subjects. Receiver-operator characteristic curve analysis was used to assess the cutoff value of PC20for the diagnosis of asthma.
  
  
  RESULTS
  Cutoff values of methacholine PC20, which provided the best combination of diagnostic sensitivity and specificity, showed an increasing pattern with age: 5.8, 9.1, 11.8, 12.6, 14.9, 21.7, 23.3, 21.1, 21.1, and 24.6 mg/mL at ages 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 years, respectively.
  
  
  CONCLUSIONS
  The application of different cutoff values of methacholine PC20depending on age might be a practical modification for the diagnosis of asthma in children and adolescents with asthmatic symptoms.
authors.affiliation: Department of Pediatrics, Chonnam National University Hospital, Gwangju, Korea.
authors.forename: Eun
authors.initials: E
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Gyeongsang National University Changwon Hospital, Changwon, Korea.
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Applied Statistics, Gachon University, Seongnam, Korea.
authors.forename: Seungbong
authors.initials: S
authors.lastname: Han
authors.affiliation: Department of Pediatrics, Hallym University Sacred Heart Hospital, Anyang, Korea.
authors.forename: Song-I
authors.initials: SI
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, Bundang CHA Medical Center, CHA University School of Medicine, Seongnam, Korea.
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Jung
authors.affiliation: Department of Pediatrics, Dankook University College of Medicine, Cheonan, Korea.
authors.forename: Ju-Hee
authors.initials: JH
authors.lastname: Seo
authors.affiliation: Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea.
authors.forename: Hyo-Bin
authors.initials: HB
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Childhood Asthma Atopy Center, Research Center for Standardization of Allergic Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Seoul National University Bundang Hospital, 82, Gumi-ro, 173 beon-gil, Bundang-gu, Songnam-si, Gyeuonggi-do, 463-707, Korea. pedas@snubh.org.
authors.forename: Ji-Won
authors.initials: JW
authors.lastname: Kwon
authors.affiliation: Department of Pediatrics, Childhood Asthma Atopy Center, Research Center for Standardization of Allergic Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Soo-Jong
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001249:Asthma / Q000175:diagnosis*; D001985:Bronchial Provocation Tests / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000008:administration & dosage*; D018721:Muscarinic Agonists / Q000008:administration & dosage*
chemical_list: D018721:Muscarinic Agonists; D016210:Methacholine Chloride
keywords: asthma; bronchial hyperresponsiveness; cutoff value; receiver-operator characteristics