Prevalence of Adverse Reactions to Gluten and People Going on a Gluten-Free Diet: A Survey Study Conducted in Brazil.

BACKGROUND: The prevalence of gluten-related disorders (GRD) and adherence to a gluten-free diet (GFD) remains unknown in Brazilian population and there is no published information on the scientific literature about the proportion of Brazilians that were diagnosed with a gluten-related disorder. Thus, the aim of this work was to estimate the prevalence of GRDs and adherence to a GFD by self-report in adult Brazilian population. MATERIALS AND METHODS: A questionnaire-based cross-sectional study was conducted in two Brazilian cities. RESULTS: The response rate was 93.2% (1630/1749). The self-reported prevalence rates were (95% CI): adverse reactions to gluten 10.06% (8.64-11.62); gluten sensitivity 2.33% (1.65-3.18); physician-diagnosed celiac disease 0.3% (0.09-0.71); non-celiac gluten sensitivity 1.71% (1.14-2.47); wheat allergy 0.79% (0.42-1.36); adherence to gluten-free diet 7.48% (6.25-8.87); gluten avoiders 15.21% (13.5-17.05). Among those who were following a GFD (n = 122), 65.6% (n = 80) of them reported that they did not develop symptoms after wheat/gluten ingestion and 50% (n = 61) were following the diet without medical/dietitian advice. The main motivation for following a GFD in the self-reported and non-self-reported gluten sensitivity groups were the symptoms triggered after wheat/gluten ingestion (86.8%) and weight control (57.1%), respectively. CONCLUSIONS: Implementation of programs to increase awareness about GRDs among healthcare professionals and giving scientifically sound information to the general population about the risks and benefits for following a GFD are desirable actions in Brazil. The results also add to the growing body of evidence for highlighting the under-diagnosis of GRD and the trend for following a GFD in Latin America.

Translation, Cultural Adaptation, and Evaluation of a Brazilian Portuguese Questionnaire to Estimate the Self-Reported Prevalence of Gluten-Related Disorders and Adherence to Gluten-Free Diet.

BACKGROUND: A Spanish version of a questionnaire intended to estimate, at the population level, the prevalence rates of self-reported gluten-related disorders and adherence to gluten-free diets has been applied in four Latin American countries. However, idiom issues have hampered the questionnaire application in the Brazilian population. Thus, the aim of the present study was to carry out a translation, cultural adaptation, and evaluation of a Brazilian Portuguese questionnaire to estimate the self-reported prevalence of gluten-related disorders and adherence to gluten-free diets in a Brazilian population. MATERIALS AND METHODS: Two bilingual Portuguese-Spanish health professionals carried out the translation of the original Spanish version of the questionnaire to Brazilian-Portuguese. Matching between the two translations was evaluated using the WCopyFind.4.1.5 software. Words in conflict were conciliated, and the conciliated version of the Brazilian Portuguese instrument was evaluated to determine its clarity, comprehension, and consistency. A pilot study was carried out using an online platform. RESULTS: The two questionnaires translated into Brazilian Portuguese were highly matched (81.8%-84.1%). The questions of the conciliated questionnaire were clear and comprehensible with a high agreement among the evaluators (n = 64) (average Kendall's W score was 0.875). The participants did not suggest re-wording of questions. The answers to the questions were consistent after two applications of the questionnaire (Cohen's k = 0.869). The pilot online survey yielded low response rates (9.0%) highlighting the need for face-to-face interviews. CONCLUSIONS: The translation and evaluation of a Brazilian Portuguese questionnaire to estimate the self-reported prevalence rates of gluten-related disorders and adherence to gluten-free diets was carried out. The instrument is clear, comprehensible, and generates reproducible results in the target population. Further survey studies involving face-to-face interviews are warranted.

Design, Assessment, and Validation of a Questionnaire to Estimate Food-Dependent Exercise-Induced Anaphylaxis Prevalence in Latin American Population.

There are no epidemiological data about food-dependent exercise-induced anaphylaxis (FDEIA) in Latin America. Our aim was to design, assess, and validate a questionnaire to identify potential FDEIA cases and/or estimate its prevalence by self-report. Questions were included in the instrument to address the main symptoms of FDEIA, type/intensity of physical activity, and anaphylaxis. The instrument's clarity, comprehension and repeatability were evaluated. These evaluations were carried out by Hispanic people (Argentinians/Colombians/Mexicans/Peruvians), including nine individuals with medical diagnosis of FDEIA, and Brazilians. The Flesch-Kincaid score was calculated using the INFLESZ software. The instrument was translated from Spanish to Brazilian Portuguese following the translation back-translation procedure. The participants rated the two versions of the questionnaire as clear and comprehensible (three-point ordinal scale) and very easy to understand [0.33; average (scale 0-10)]. For these evaluations, the Kendall's W coefficient showed strong agreement among raters (W = 0.80; average). The Flesch-Kincaid score was 63.5 in average (documents considered as readable). The Cohen's Kappa coefficient showed almost perfect agreement in repeatability (0.88; average). The validation process of two versions of an instrument, used to identify potential FDEIA cases, was successfully carried out and it was found applicable to Latin American countries for generating epidemiological data.