title: Morning Salivary Cortisol in Young Children: Reference Values and the Effects of Age, Sex, and Acute Bronchiolitis.
abstract: To identify morning salivary cortisol reference values in infancy and at 2 years of age and to investigate the influence of age, sex and acute bronchiolitis.
  
  
  
  In this South-East Norwegian cohort study, 308 children hospitalized with moderate to severe acute bronchiolitis in infancy in 2010-2011 were compared with 223 healthy controls included in 2012 by measuring morning salivary cortisol levels at inclusion and at 2 years of age. Samples were collected shortly after awakening after 6 am. The influences of age, sex, and acute bronchiolitis were assessed by regression analysis.
  
  
  
  In infancy, cortisol values were higher in acute bronchiolitis, with an age- and sex-adjusted weighted mean group difference of 13.9 nmol/L (95% CI 8.1-19.7; P < .0001). The median level in reference group was 23.7 nmol/L (95% CI 9.7-119.6). At 2 years of age, sex but not inclusion groups differed, with significantly higher values in girls. The weighted mean of all boys' cortisol levels was 32.4 nmol/L, (95% CI 30.5-34.3), and all girls' levels were 36.9 nmol/L (95% CI 34.7-39.2; P < .003).
  
  
  
  Salivary cortisol levels were higher at 2 years of age than in infancy in the reference group, were higher in girls than in boys at 2 years of age, and were higher in infants at the time of acute bronchiolitis than in healthy infants.
  
  
  
  ClinicalTrials.gov: NCT00817466.
authors.affiliation: Department of Pediatrics, Innlandet Hospital Trust, Elverum, Norway; Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Norway; Faculty of Medicine, Institute of Clinical Medicine, University of Oslo. Electronic address: rolfl@sykehuset-innlandet.no.
authors.forename: Leif Bjarte
authors.initials: LB
authors.lastname: Rolfsjord
authors.affiliation: Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Norway.
authors.forename: Egil
authors.initials: E
authors.lastname: Bakkeheim
authors.affiliation: Faculty of Medicine, Institute of Clinical Medicine, University of Oslo; Department of Dermatology, Oslo University Hospital, Norway.
authors.forename: Teresa Løvold
authors.initials: TL
authors.lastname: Berents
authors.affiliation: Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden; Sachs' Children and Youth Hospital, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Alm
authors.affiliation: Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Norway; Faculty of Medicine, Institute of Clinical Medicine, University of Oslo.
authors.forename: Håvard Ove
authors.initials: HO
authors.lastname: Skjerven
authors.affiliation: Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Norway; Faculty of Medicine, Institute of Clinical Medicine, University of Oslo.
authors.forename: Kai-Håkon
authors.initials: KH
authors.lastname: Carlsen
authors.affiliation: Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Norway.
authors.forename: Petter
authors.initials: P
authors.lastname: Mowinckel
authors.affiliation: Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden; Starbovägen 47, Vällingby, Sweden.
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Sjöbeck
authors.affiliation: Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Norway; Faculty of Medicine, Institute of Clinical Medicine, University of Oslo.
authors.forename: Karin Cecilie Lødrup
authors.initials: KCL
authors.lastname: Carlsen
mesh_terms: D000208:Acute Disease; D000367:Age Factors; D001988:Bronchiolitis / Q000378:metabolism; D002675:Child, Preschool; D002940:Circadian Rhythm; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000096:biosynthesis; D007223:Infant; D008297:Male; D012016:Reference Values; D012463:Saliva / Q000737:chemistry*; D012720:Severity of Illness Index; D012737:Sex Factors
chemical_list: D006854:Hydrocortisone
keywords: adrenocortical function; allergic disease; allergic rhinitis; asthma; health-related quality of life; infants; morning salivary cortisol; stress; toddlers