Development and preliminary validation of the food intolerance Quality of Life Questionnaire (FIQLQ): Adult Form
Approximately 20% of children and adults avoid certain foods because of perceived food intolerance. Valid and reliable health-related quality of life instruments are needed to measure changes following clinical, therapeutic or policy interventions. However, there are no disease-specific quality of life instruments for adults with food intolerances.
To develop the Food Intolerance Quality of Life Questionnaire FIQLQ. Then to conduct psychometric validation including reliability and construct validity.
We adapted the existing Food Allergy Quality of Life questionnaire (FAQLQ) for interviews with 14 adults with food intolerance. For preliminary psychometric validation, 229 adults with food intolerances completed the online electronic version of FIQLQ.
The resultant FIQLQ had 18 items which loaded onto 3 subscales—Emotional Impact, Social and Dietary Restrictions, Reactions and Avoidance. Each subscale had excellent internal consistency reliability (Cronbach’s α 0.81–0.94). Content, convergent and construct validity was supported by significant correlations of FIQLQ subscale scores with hypothesised variables including age, numbers of symptoms and level of stress experienced due to intolerance.
The FIQLQ has good reliability, construct validity and internal consistency. It is short and easy to use, providing a good tool for evaluating quality of life in the clinical research setting and to inform health and regulatory policies.
KeywordsFood intolerance Food venues Validation Consumer Patient Health-related quality of life Measurement Regulation Outcomes
This study was funded by the UK Food Standards Agency under project code FS305013. The research based at University of Southampton was further supported by The Asthma, Allergy and Inflammation Research Charity (AAIR).
JB and JL conceived the study and were involved in design and co-ordination of study. ADG drafted the paper and carried out data analysis. KR and FB collected data and assisted in data analysis. All authors helped in the final editing of paper and all authors read and approved the final manuscript.
Compliance with ethical standards
Conflict of interest
No competing interests for any of the authors, according to BioMed Central criteria.
The Research Ethics Committee of the School of Applied Psychology, UCC, provided approval for the study. Data were stored in compliance with data protection laws.
Consent for participation and publication
Consent for participation and publication form was provided and signed by all participants in all phases of the study prior to participation. Available on request.
Availability of data and material
Data are stored in compliance with data protection laws in School of Applied Psychology, University College Cork, College Rd., Cork City, Ireland, and Department of Psychology, University of Bath, Claverton Down, Bath, North East Somerset BA2 7AY, United Kingdom.
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