title: Food allergy-related quality of life after double-blind, placebo-controlled food challenges in adults, adolescents, and children.
abstract: BACKGROUND
  Currently, the longitudinal validity (validity over time) and responsiveness (ability to measure change over time) of the Food Allergy Quality of Life Questionnaire-Adult Form (FAQLQ-AF), the Food Allergy Quality of Life Questionnaire-Teenager Form (FAQLQ-TF), and the Food Allergy Quality of Life Questionnaire-Child Form (FAQLQ-CF) are unknown. Additionally, the self-reported impact of a double-blind, placebo-controlled food challenge (DBPCFC) on health-related quality of life (HRQL) in adults (≥18 years of age), adolescents (13-17 years of age), and children (8-12 years of age) is unknown.
  
  
  OBJECTIVE
  The aims of this study were to assess the longitudinal validity and responsiveness of the FAQLQ-AF, FAQLQ-TF, and FAQLQ-CF and to assess the impact of a DBPCFC on HRQL.
  
  
  METHODS
  Two hundred twenty-one participants suspected of food allergy were included from Dutch allergy centers. Participants undergoing a DBPCFC (experimental group) completed the FAQLQ and Food Allergy Independent Measure (FAIM) 1 month before (baseline) and 6 months after (follow-up) a DBPCFC. Participants not undergoing a DBPCFC (control group) completed the questionnaire package twice with a 7-month interval.
  
  
  RESULTS
  HRQL scores improved after a DBPCFC, with greater improvements in HRQL scores after a negative outcome (food allergy ruled out) than a positive outcome (food allergy confirmed), demonstrating responsiveness of the FAQLQs. Significant correlations were shown between the change (follow-up minus baseline) in FAQLQ and FAIM scores supporting longitudinal validity of these questionnaires: FAQLQ-AF (Pearson correlation coefficient = 0.71, P < .001), FAQLQ-TF (Pearson correlation coefficient = 0.35, P = .018), and FAQLQ-CF (Pearson correlation coefficient = 0.51, P < .001).
  
  
  CONCLUSIONS
  Our findings demonstrate the longitudinal validity and responsiveness of the FAQLQs. Greater improvements in HRQL scores were shown after a negative outcome than after a positive outcome.
authors: Department of Pediatrics, Division of Pediatric Pulmonology and Pediatric Allergy, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. j.l.van.der.velde@umcg.nl
authors: Jantina L
authors: JL
authors: van der Velde
authors: Bertine M J
authors: BM
authors: Flokstra-de Blok
authors: Hans
authors: H
authors: de Groot
authors: Joanne N G
authors: JN
authors: Oude-Elberink
authors: Marjan
authors: M
authors: Kerkhof
authors: Eric J
authors: EJ
authors: Duiverman
authors: Anthony E J
authors: AE
authors: Dubois
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004311:Double-Blind Method; D005500:Follow-Up Studies; D005512:Food Hypersensitivity / Q000175:diagnosis*; D006801:Humans; D007114:Immunization; D009426:Netherlands; D015990:Placebo Effect; D011379:Prognosis; D011788:Quality of Life; D015203:Reproducibility of Results; D057566:Self Report; D012680:Sensitivity and Specificity