Development of a screening questionnaire for the study of food allergy in adults

Carlos Lozoya-Ibáñez; João Belo; Rosa M Afonso; Henrique Pereira; Alexandra Rodrigues; Luís Taborda-Barata

doi:10.1016/j.waojou.2020.100456

Development of a screening questionnaire for the study of food allergy in adults

World Allergy Organ J. 2020 Aug 22;13(9):100456. doi: 10.1016/j.waojou.2020.100456. eCollection 2020 Sep.

Authors

Carlos Lozoya-Ibáñez^{1

2

3}, João Belo^{3

4}, Rosa M Afonso^{3

5}, Henrique Pereira^{3

5}, Alexandra Rodrigues^{3

6}, Luís Taborda-Barata^{2

3

7}

Affiliations

¹ Allergy Department, Castelo Branco Local Health Unit, Castelo,Branco, Portugal.
² CICS-Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.
³ CACB-Clinical Academic Center of Beiras, Portugal.
⁴ Polytechnic Institute of Castelo Branco, Escola Superior de Saúde Dr. Lopes Dias, Castelo Branco, Portugal.
⁵ Psychology and Education Department, University of Beira Interior, Covilhã, Portugal.
⁶ Outpatient Clinic Department, Castelo Branco Local Health Unit, Portugal.
⁷ Department of Allergy & Clinical Immunology, Cova da Beira University Hospital Centre, Covilhã, Portugal.

Abstract

Background & aims: As far as we know, no screening questionnaire has been developed and validated for identification of adverse food reactions in Portuguese-speaking adults, as an initial approach towards the investigation of cases of possible food allergy. Thus, the objective of this study was to develop and validate a screening questionnaire of food allergy in adult Portuguese-speaking patients.

Methods: This was a multicentre, cross-sectional study using a simple random sample of 186 adults between 18 and 82 years old from various parts of the centre of Portugal. Intelligibility of the questionnaire was first assessed in 24 patients with confirmed IgE- or non-IgE-mediated food allergy, and in 24 volunteers without food allergies. The 17-item questionnaire was subsequently applied by phone to 78 food allergic patients (66 IgE-mediated and 12 non-IgE mediated) and to 60 non-food allergic volunteers, with subsequent reassessment (re-test). Face and content validity, intelligibility, construct validity, and test-retest reliability (temporal stability) were analysed.

Results: Face and content validity allowed item reduction from 30 to 17 items with adequate content validity index >0.78. Construct validity was confirmed in the 66 confirmed IgE-mediated food allergic patients, 12 non-IgE-mediated food allergic patients, and 60 non-allergic patients. Test-Retest Reliability (general temporal stability) of the test had a Spearman correlation coefficient value of 0.845 for the retest. Cohen's Kappa values for the relevant questions were greater than 0.890 for almost all items. No differences were found when sex, age, and volunteers' recruitment origin were analysed. An inverse relationship was found between reliability and retest time interval.

Conclusions: Due to the quick and easy implementation, confirmation of face, content and construct validity as well as high temporal reproducibility, this screening questionnaire may be a useful study tool for an initial approach to detection of food allergies in adults.

Keywords: Adults; Adverse food reactions; Food allergy; Questionnaire; Validation.