Purpose: To assess the association between birth weight and the development of functional gastrointestinal disorders (FGIDs) in the first year of life. Methods: This is a secondary analysis of a prospective cohort multicenter study including neonates, consecutively enrolled at birth, and followed up for one year. At birth all infants were classified by birth weight as extremely low (ELBW), very low, or low when <1,000, <1,500, and <2,500 g, respectively, and by birth weight for gestational age as appropriate (AGA, weight in the 10–90th percentile), small (SGA, weight <10th percentile), and large (LGA, weight >90th percentile) for gestational age. FGIDs were classified according to the Rome III criteria and assessed at 1, 3, 6, and 12 months of life. Results: Among 1,152 newborns enrolled, 934 (81.1%) completed the study: 302 (32.3%) were preterm, 35 (3.7%) were ELBW, 104 (11.1%) were SGA, 782 (83.7%) were AGA, and 48 (5.1%) were LGA infants. Overall, throughout the first year of life, 718 (76.9%) reported at least one FGID. The proportion of infants presenting with at least one FGID was significantly higher in ELBW (97%) compared to LBW (74%) (p=0.01) and in LGA (85.4%) and SGA (85.6%) compared to AGA (75.2%) (p=0.0001). On multivariate analysis, SGA was significantly associated with infantile colic. Conclusion We observed an increased risk of FGIDs in ELBW, SGA, and LGA neonates. Our results suggest that prenatal factors determining birth weight may influence the development of FGIDs in infants. Understanding the role of all potential risk factors may provide new insights and targeted approaches for FGIDs.

Background/Aims: Since available data on pediatric non-erosive esophageal phenotypes (NEEPs) are scant, we investigated their prevalence and the phenotype-dependent treatment response in these children. Methods: Over a 5-year period, children with negative upper endoscopy, who underwent esophageal pH-impedance (off-therapy) for persisting symptoms not responsive to proton pump inhibitor (PPI)-treatment, were recruited. Based on the results of acid reflux index (RI) and symptom association probability (SAP), patients were categorized into: (1) abnormal RI (non-erosive reflux disease [NERD]), (2) normal RI and abnormal SAP (reflux hypersensitivity [RH]), (3) normal RI and normal SAP (functional heartburn [FH]), and (4) normal RI and not-reliable SAP (normal-RI-not otherwise-specified [normal-RI-NOS]). For each subgroup, treatment response was evaluated. Results: Out of 2333 children who underwent esophageal pH-impedance, 68 cases, including 18 NERD, 14 RH, 26 FH, and 10 normal-RI-NOS were identified as fulfilling the inclusion criteria and were analyzed. Considering symptoms before endoscopy, chest pain was more reported in NERD than in other cases (6/18 vs 5/50, P = 0.031). At long-term follow-up of 23 patients (8 NERD, 8 FH, 2 RH, and 5 normal-RI-NOS): 17 were on PPIs and 2 combined alginate, 1 (FH) was on benzodiazepine + anticholinergic, 1 (normal-RI-NOS) on citalopram, and 3 had no therapy. A complete symptom-resolution was observed in 5/8 NERD, in 2/8 FH, and in 2/5 normal-RI-NOS. Conclusions FH may be the most common pediatric NEEP. At long-term follow-up, there was a trend toward a more frequent complete symptom resolution with PPI-therapy in NERD patients while other groups did not benefit from extended acid-suppressive-treatment.