Evaluation of the measurement properties of the Brazilian version of two quality-of-life questionnaires in food allergy – for children and their parents

OBJECTIVE: To evaluate the psychometric properties of the Brazilian version of health-related quality-of-life questionnaires of children with food allergy and their parents. METHODS: The translation and cultural adaptation processes were previously performed, according to the method proposed by the World Health Organization. After this stage, the questionnaires were applied to 201 parents of children under 6 years of age with food allergy. The assessment of the psychometric properties included: evaluation of the internal consistency by Cronbach's alpha coefficient; of the reproducibility by the intraclass correlation coefficient between test and retest; and of the construct, using Spearman's correlation coefficient, comparing the obtained scores with those of generic questionnaires that evaluate health-related quality of life. RESULTS: The means of the obtained scores were 2.44 and 3.35, for the children and their parents, respectively. Cronbach's alpha coefficients were 0.85 and 0.91, respectively, which showed good internal consistency of the tools. The intraclass correlation coefficients between test and retest were 0.87 and 0.84 for children and their parents, respectively, showing good reproducibility for both questionnaires. The correlation between the specific and the generic questionnaires was significant (-0.27 for the children, -0.64 for their parents, p<0.05). CONCLUSIONS: The specific questionnaires to evaluate the health-related quality of life of children with food allergy and of their parents were satisfactorily validated to be used in Brazil.