An Examination of the Food Allergy Quality of Life Questionnaire Performance in a Countrywide American Sample of Children: Cross-Cultural Differences in Age and Impact in the United States and Europe

Background It is important to ensure that tools are valid and reliable in the context in which they are used. The development of age and country norms is part of this process. Objectives The primary aim of the present study was to examine the performance of the Food Allergy Quality of Life Questionnaire – Parent Form (FAQLQ-PF) in a countrywide American sample of children with food allergy. The secondary aim was to compare age differences in impact across 9 European countries. Methods In a cross-sectional quantitative design, questionnaires were completed by the parents of 1029 food-allergic children (0-12 years). Participants were recruited via support groups and allergists. Data were analyzed by using multivariate analysis of variance and tests for internal consistency and validity. The average score was calculated for each age group in 15 studies in Ireland, Switzerland, the Netherlands, Spain, Portugal, Germany, Italy, Denmark, Israel, and the United Kingdom. Results The FAQLQ-PF has high convergent validity (child: r = 0.49, n = 695, P =.01; parent: r = 0.36, n = 696, P =.01) and discriminant validity, parent: t (719) = 4.67, P =.001 (anaphylaxis yes vs no); t (513), P =.009 (single vs multiple allergens). Internal consistency was excellent (r = 0.96). US health-related quality of life was worse than European health-related quality of life, as indicated by higher FAQLQ-PF scores in US samples. Burden increased with age in all populations. Conclusions The FAQLQ-PF is appropriate for use in an American population. Findings will form the basis for further work in the development of an online manual with food allergy–normed age scores to allow for precise measurement, interpretation of scores, and comparison across countries and cultures, in clinical and research settings.