title: Cortisol diurnal rhythm and stress reactivity in constipation and abdominal pain: the Generation R Study.
abstract: OBJECTIVE
  The aim of this study was to assess whether diurnal cortisol rhythm and cortisol stress reactivity were associated with functional constipation and abdominal pain in infancy.
  
  
  METHODS
  This study was embedded in a subset of the Generation R Study, a prospective cohort study from fetal life onward in Rotterdam, the Netherlands. Data of infants between 14 and 24 months of age (N =483) were used. Salivary cortisol diurnal rhythm and salivary cortisol stress reactivity after a Strange Situation Procedure were assessed at age 14 months. Data on functional constipation were available according to the Rome II criteria, and data on abdominal pain on the basis of the Abdominal Pain Index were available from questionnaire data at 24 months.
  
  
  RESULTS
  In the second year of life, 13% of the infants had functional constipation and 17% had abdominal pain. Only 4% had symptoms of both functional constipation and abdominal pain. Diurnal cortisol rhythm did not differ significantly between children with and children without functional constipation and abdominal pain. Cortisol stress reactivity was slightly higher in infants with abdominal pain than in those without it, but this was not statistically significant (odds ratio 1.41; 95% confidence interval 0.46-4.31). No association was found between the cortisol stress reactivity and functional constipation.
  
  
  CONCLUSIONS
  Our results suggest that cortisol as a marker for stress does not play a major role in functional constipation or abdominal pain in infancy.
authors.affiliation: The Generation R Study Group, Erasmus University Medical Centre, Rotterdam, The Netherlands.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Kiefte-de Jong
authors.forename: Nathalie S
authors.initials: NS
authors.lastname: Saridjan
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Escher
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: Henning
authors.initials: H
authors.lastname: Tiemeier
authors.forename: Henriette A
authors.initials: HA
authors.lastname: Moll
mesh_terms: D015746:Abdominal Pain / Q000139:chemically induced / Q000503:physiopathology*; D019540:Area Under Curve; D015415:Biomarkers / Q000032:analysis; D002675:Child, Preschool; D002940:Circadian Rhythm; D003248:Constipation / Q000139:chemically induced / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000378:metabolism*; D007223:Infant; D016014:Linear Models; D008297:Male; D009426:Netherlands; D011446:Prospective Studies; D012463:Saliva / Q000737:chemistry; D013312:Stress, Physiological; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone