To the Editor, We read with great interest the article by Morales-Romero et al. 1, which provides valuable data on the prevalence of adverse food reactions and food allergy (FA) among adults in western Mexico. Their finding that self-reported FA prevalence has remained stable over a decade is an important contribution in a country with limited epidemiological data on FA. The authors rightly acknowledge that survey-based studies may overestimate the prevalence of FA, highlighting the need for studies incorporating objective diagnostic criteria. In this context, we wish to share our experience from a population-based study on FA in northwestern Mexico, which highlights the challenge of estimating FA prevalence rates based on objective diagnostic criteria in our country. We conducted a 2-phase, cross-sectional study in a representative sample of adults (n = 834) from Culiacán, Sinaloa, using a validated questionnaire. Suspected cases of immediate-type FA were identified in phase 1, and skin prick tests (SPTs) were performed in phase 2 (the Research Ethics Committee of the Center for Research and Teaching in Health Sciences from the Autonomous University of Sinaloa approved the study, Registry No. 191-2025). Eighteen participants met the criteria to undergo SPTs (no medical diagnosis of FA, but suspected of it), but only 3 of them (16.7%) agreed to take the test, which hampered a statistically robust estimation of SPT-positive FA prevalence. Certainly, a positive SPT does not guarantee a clinical reaction to the suspected food, but a negative one has a high negative predictive value, allowing us to make estimates closer to the real prevalence than when only surveys are conducted. In fact, food sensitization was confirmed in 2 of the 3 cases tested in our study (Table 1). We speculate that the low response rate at follow-up for performing SPTs may stem from factors common in the research field, such as fear of medical procedures, logistical barriers for participants, or a general distrust, which are significant obstacles to consider 2. Table 1. - Demographic characteristics and SPT results of participants with suspected FA Participant ID 010 Participant ID 014 Participant ID 018 Age (years) 25 26 21 Sex Female Female Male Positive control 8 mm 6 mm 6 mm Negative control 1 mm 1 mm 0 mm Raw fish 4 mm (+) Not evaluated Not evaluated Cooked fish 5 mm (+) Not evaluated Not evaluated Raw shrimp Not evaluated 0 mm (−) 6 mm (+) Cooked shrimp Not evaluated 1 mm (−) 7 mm (+) Tomato Not evaluated Not evaluated 2 mm (−) Results of 3 adults from Culiacán, Sinaloa, with suspected IgE-mediated FA without a prior medical diagnosis. Skin prick tests (SPTs) were performed using the prick-by-prick technique with fresh foods (raw and cooked). A positive control (histamine) and a negative control (saline solution) were included for each participant. The test was read after 15–20 minutes, and a result was considered positive (+) when the wheal diameter was ≥3 mm larger than the negative control. A negative result (−) was indicated by a wheal diameter <3 mm. All participants showed an adequate response to the positive control and no reaction to the negative control, confirming the validity of the tests. Undoubtedly, methodological barriers will arise in estimating the prevalence of FA at the population level in Mexico if we want to go beyond what can be estimated using validated questionnaires. Certainly, survey studies in the Mexican population 1,3–5 are essential for broad surveillance, but in our experience, epidemiological data on FA based on objective diagnostic criteria remain unachievable in some regions of Mexico due to the loss of participants at follow-up. Therefore, designing FA prevalence studies in Mexico should focus first on integrating robust strategies for enhancing participation rates in diagnostic confirmation phases. Conflicts of interest The authors have no financial conflicts of interest. Author contributions Conceptualization: Jesús G. Arámburo-Gálvez and Noé Ontiveros. Investigation: Lizbeth Vizcarra-Olguin, Oscar G. Figueroa-Salcido, and Juancarlos M. Velásquez-Rodríguez. Methodology: Lizbeth Vizcarra-Olguin and Oscar G. Figueroa-Salcido. Validation: Juancarlos M. Velásquez-Rodríguez. Project administration: Noé Ontiveros. Supervision: Jesús G. Arámburo-Gálvez. Writing—original draft: Jesús G. Arámburo-Gálvez and Noé Ontiveros. Writing—review and editing: Lizbeth Vizcarra-Olguin, Juancarlos M. Velásquez-Rodríguez, and Oscar G. Figueroa-Salcido.
Arámburo-Gálvez et al. (Tue,) studied this question.