To the Editor: With respect to the article by Zeevenhooven et al (1), its statistical strengths related to oversaling, with significance levels <0.10 in univariate logistic regression analysis and the fit-of-multiple tests with Bonferroni <0.002, are highlighted. How did the researchers, however, extrapolate questions related to the evolution times of the functional gastrointestinal disorders (FGDs), given that they administered the Questionnaire on Pediatric Gastrointestinal Symptoms (QPGS)-III over 8 weeks and the QPGS-IV over 4 weeks? Moreover, has the questionnaire used in part 2 about psychosocial factors been validated? As the QPGS-IV classifies irritable bowel syndrome (IBS) into 4 subtypes and the QPGS-III includes questions about the consistency of the feces, is it possible to determine this classification, as other authors have (2–5)? The authors’ interpretation of the highest frequency of FGDs associated with abdominal pain is that among other factors, children from Curacao (1) have a much higher frequency of IBS and are older than children from Colombia (6) and the USA (7). This high frequency of IBS, however, could also be explained as the QPGS-III, unlike the QPGS-IV, does not include questions about the presence of pain only when girls are menstruating or about improvement in constipation when using medications. Finally, one of the weaknesses of the study is that the researchers failed to identify the group of FGDs associated with nausea and vomiting; therefore, as they do not describe their 2 subtypes, functional dyspepsia would also be a valid possibility.