1King's College London, Department of Psychology, London, UK.
2King's College London, Diabetes and Nutritional Sciences Division, London, UK.
3King's College London, Health and Social Care Division, London, UK.
4Frimley Park Hospital NHS Foundation Trust, Department of Gastroenterology, Frimley, UK.
5King's College London, Diabetes and Nutritional Sciences Division, London, UK Guys and St Thomas' NHS Foundation Trust, Department of Nutrition & Dietetics, London, UK Guys and St Thomas' NHS Foundation Trust, Department of Gastroenterology, London, UK.
6Barts and the London School of Medicine and Dentistry, Blizard Institute, Queen Mary University of London, London, UK Digestive Diseases Unit, Barts Health NHS Trust, London, UK.
7King's College London, Diabetes and Nutritional Sciences Division, London, UK email@example.com.
Psychosocial factors surrounding eating and drinking, such as enjoying food, managing restrictions, and maintaining social relationships, remain under-researched in inflammatory bowel disease [IBD]. This study aimed to develop and validate a food-related quality of life [FR-QoL] questionnaire to systematically measure these issues in the IBD population.
Following semi-structured interviews with 28 IBD patients, 150 potential questionnaire items were generated. These were ranked by 100 IBD patients, and items were removed based on ceiling/floor effects and high inter-item correlations [> 0.7], with 41 items being retained. In total, 323 IBD patients, 100 asthma patients [chronic disease control], and 117 healthy controls completed the FR-QoL questionnaire, alongside generic and disease-specific QoL and food satisfaction questionnaires. Principal components analysis [PCA], construct and discriminant validity, and test-retest reliability were calculated.
Twelve items were removed following PCA. The reduced questionnaire [FR-QoL-29] explained 63.9% of the variance [Cronbach's α = 0.96]. FR-QoL-29 correlated significantly with generic QoL [r = 0.697], depression [r = -0.519], anxiety [r = -0.531], and food satisfaction [r = 0.701]. The FR-QoL-29 sumscores were significantly lower for IBD (89.5, standard deviation [SD] 28.6) than asthma [125.4, SD 24.1; p < 0.001] and healthy volunteers [123.0, SD 16.5; p<0.001]. Within IBD, worse food-related QoL was found in those with moderate/high disease activity [66.7, SD 22.1] compared with remission/low disease activity [92.5, SD 28.1]. Test-retest reliability was good (intra-class correlation [ICC] = 0.83, 95% confidence interval [CI] = 0.76:0.88).
The FR-QoL-29 shows good reliability and validity across a range of IBD characteristics. This easily administered questionnaire is a useful tool in identifying poor food-related QoL and in the future may identify areas for intervention.