Supplementary Material for: Adult Food Allergy Prevalence: Reducing Questionnaire Bias

<p><b><i>Background:</i></b> Food allergy (FA) prevalence has increased in the last decades, but epidemiologic studies could show overestimated results. The objective of this study is to estimate the prevalence of immediate FA in adults in a region of Central Brazil, using a questionnaire to try to reduce misperceptions about FA reaction. <b><i>Methods:</i></b> A cross-sectional study was conducted, enrolling an adult population aged 18-65 years comprised of families in a Central Brazilian city. In the first phase, participants answered a self-administered questionnaire for FA screening. In the second phase, the participants who reported an FA in the first questionnaire were visited to complete the second questionnaire applied by trained researchers. <b><i>Results:</i></b> Of the 4,916 adults visited, 1,583 returned a completed questionnaire. Reported FA occurred in 171 (10.8%) subjects, and the more frequent citations were cow's milk, pork, fruits, shrimp, and vegetables. One hundred and four of these individuals completed the second questionnaire, and 15 (1.0%) were considered to have an FA diagnosis. The main foods were fruits, followed by cow's milk, shrimp, pork, and vegetables. <b><i>Conclusion:</i></b> After use of a specific questionnaire to recognize possible IgE-mediated FAs, a low frequency of FA was considered in this population. Use of a directed questionnaire administered by trained researchers could be an alternative for epidemiological IgE-mediated FA studies to achieve more accurate results.</p