Development and validation of the self-administered Food Allergy Quality of Life Questionnaire for adolescents

Background: Food allergy can affect health-related quality of life (HRQL). Currently, no validated, self-administered, disease-specific HRQL questionnaire for adolescents with food allergy exists. Objective: We sought to develop and validate the Food Allergy Quality of Life Questionnaire-Teenager Form (FAQLQ-TF) in the Dutch language. Methods: Ten adolescents (13-17 years) with food allergy were interviewed and generated 166 HRQL items. The most important items were identified by 51 adolescents with food allergy by using the clinical impact method, resulting in the FAQLQ-TF containing 28 items (score range: 1 no impairment to 7 maximal impairment). The FAQLQ-TF, the Food Allergy Independent Measure, and a generic HRQL questionnaire (CHQ-CF87) were sent to 98 adolescents with food allergy for cross-sectional validation of the FAQLQ-TF. Results: Construct validity was assessed based on the correlation between the FAQLQ-TF and the Food Allergy Independent Measure (rho = 0.57, P <.001). The FAQLQ-TF had excellent internal consistency (Cronbach alpha =.92) and discriminated between adolescents who differed in number of food allergies (1 vs >2 food allergies: total FAQLQ-TF score, 4.3 vs 3.5; P = 0.037) but did not discriminate between those who did or did not have reported anaphylaxis. The FAQLQ-TF correlated weakly with 6 of the 11 CHQ-CF87 scales, demonstrating convergent/discriminant validity. Conclusion: The FAQLQ-TF is the first self-administered, disease-specific HRQL questionnaire for adolescents with food allergy. It has good construct validity and excellent internal consistency and discriminates between adolescents who differ in the number of food allergies. The FAQLQ-TF is short: and easy to use and might therefore be a useful tool in clinical research.