title: The prevalence of CMA/CMPI in young children: the validity of parentally perceived reactions in a population-based study.
abstract: BACKGROUND
  The present study aimed to estimate the prevalence of adverse reactions to milk, as population-based prevalence estimates based on objective diagnostic procedures are rare.
  
  
  METHODS
  Children with parentally reported reactions to milk were selected for further examination from a population-based cohort of 2721 children. At the age of 2(1/2) years, they underwent a stepwise diagnostic procedure that included diet trials at home, skin prick tests, and open and double-blind, placebo-controlled food challenges. A sample of children with symptoms not attributed to milk was selected for assessment of unrecognized reactions.
  
  
  RESULTS
  The estimated point prevalence of cow's milk allergy and cow's milk protein intolerance (CMA/CMPI) in children with parentally perceived reactions at the age of 2(1/2) years was estimated to be 1.1% (CI 0.8-1.6). However, this was an underestimate, as unrecognized reactions were detected. Most reactions were not IgE-mediated. The positive predictive value of a parentally perceived reaction depended on the number of times it had been reported and was good for reactions reported three times (at 12, 18, and 24 months of age).
  
  
  CONCLUSIONS
  The present study confirms previous findings that parents overestimate milk as a cause of symptoms in their children; however, it also indicates that unrecognized reactions may be a problem as well.
authors.affiliation: National Institute of Public Health, Section of Epidemiology, Department of Population Health Sciences, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Eggesbø
authors.forename: G
authors.initials: G
authors.lastname: Botten
authors.forename: R
authors.initials: R
authors.lastname: Halvorsen
authors.forename: P
authors.initials: P
authors.lastname: Magnus
mesh_terms: D017677:Age Distribution; D017668:Age of Onset; D001294:Attitude to Health; D015982:Bias; D002675:Child, Preschool; D015331:Cohort Studies; D004311:Double-Blind Method; D006801:Humans; D015994:Incidence; D007428:Intradermal Tests; D016269:Milk Hypersensitivity / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology; D008894:Milk Proteins / Q000009:adverse effects*; D009664:Norway / Q000453:epidemiology; D010290:Parents / Q000523:psychology*; D011159:Population Surveillance / Q000379:methods; D011237:Predictive Value of Tests; D015995:Prevalence; D011795:Surveys and Questionnaires / Q000592:standards*
chemical_list: D008894:Milk Proteins