title: Effect of age on fructose malabsorption in children presenting with gastrointestinal symptoms.
abstract: OBJECTIVE
  Fructose malabsorption can produce symptoms such as chronic diarrhoea and abdominal pain. Here, we retrospectively review breath hydrogen test (BHT) results to determine whether age has an effect on the clinical application of the fructose BHT and compare this with the lactose BHT.
  
  
  METHODS
  Patients were referred to a gastroenterology breath-testing clinic (2003-2008) to investigate carbohydrate malabsorption as a cause of gastrointestinal symptoms. Patients received either 0.5 g/kg body weight of fructose (maximum of 10 g) or 2 g/kg of lactose (maximum of 20 g), in water, and were tested for 2.5 hours.
  
  
  RESULTS
  Patient age showed a significant effect on the fructose BHT results (P < 0.001, 0.1-79 years old, n = 1093). The odds of testing positive for fructose malabsorption in paediatric patients (15 years old or younger, n = 760) decreased by a factor of 0.82/year (95% confidence interval 0.79-0.86, P < 0.001). There were 88.2% positive in younger than 1-year-olds, 66.6% in 1- to 5-year-olds, 40.4% in 6- to 10-year-olds, and 27.1% in 10- to 15-year-olds. In contrast, 39.3% of lactose BHTs were positive, with no significant relation between patient age and test result (P = 0.115, 0.1-89 years old, n = 3073).
  
  
  CONCLUSIONS
  The majority of infants with gastrointestinal symptoms exhibited fructose malabsorption, but the capacity to absorb fructose increased with patient age up to 10 years old. The low threshold for fructose absorption in younger children has significant implications for the performance and interpretation of the fructose BHT and for the dietary consumption of fructose in infants with gastrointestinal symptoms.
authors.affiliation: Cell Biology of Disease Research Group and PERI Centre, Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia.
authors.forename: Hilary F
authors.initials: HF
authors.lastname: Jones
authors.forename: Esther
authors.initials: E
authors.lastname: Burt
authors.forename: Kate
authors.initials: K
authors.lastname: Dowling
authors.forename: Geoff
authors.initials: G
authors.lastname: Davidson
authors.forename: Doug A
authors.initials: DA
authors.lastname: Brooks
authors.forename: Ross N
authors.initials: RN
authors.lastname: Butler
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001944:Breath Tests / Q000379:methods; D002648:Child; D004040:Dietary Carbohydrates / Q000378:metabolism*; D005260:Female; D005632:Fructose / Q000378:metabolism*; D005767:Gastrointestinal Diseases / Q000209:etiology* / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D008286:Malabsorption Syndromes / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D005632:Fructose; D006859:Hydrogen