Development and preliminary validation of the Food Intolerance Quality of Life Questionnaire (FIQLQ): Parent, Teenager and Child Forms

"Background: A significant proportion (up to 20%) of children and young people avoid food due a perceived food hypersensitivity. Disease-specific quality-of-life scales are needed to measure the impact of living with a food hypersensitivity on physical, psychological and social wellbeing. Although quality-of-life scales exist for children and young people with a food allergy and coeliac disease and a proxy version for parents, there is only an adult version for food intolerance.Aims: This study aimed to develop the child (aged 8-12 years), teenager (aged 13-17 years) and a parent proxy (for parents of children aged 0-17 years) versions of the Food Intolerance Quality of Life Questionnaire (FIQLQ).Methods: We adapted the existing child and teenager version of the Food Allergy Quality of Life Questionnaire (FAQLQ) following interviews with two teenagers. There was a pre-existing but unvalidated version of the parent FIQLQ that had already been adapted from the FAQLQ. 29 children, 39 teenagers and 132 parents completed the relevant FIQLQ along with general questions about their food intolerance and experience of living with intolerance (as part of a broader study funded by the Food Standards Agency).Results: All three versions of the FIQLQs had excellent internal consistency for the subscales and total scores (Cronbach’s ⍺ 0-83-0.97). The parent version was analysed through Principal Component Analysis, resulting in a 23-item measure with three subscales: Dietary Impact, Emotional Impact and Social Impact. Construct validity with hypothesised variables including perceived severity of intolerance, age, and quality-of-life measured through the EQ-5D-Y suggested that the scales might be valid, but further validation with larger samples is needed.Conclusion: The child, teenager and parent proxy versions of the FIQLQ have been developed and have excellent internal consistency. They are quick and easy to use but need further validation to confirm the findings.