P4.047: Gut Instincts: Understanding Early-Life Gastroenteritis and Its Epidemiologic Impact on Pediatric Functional GI Disorders

Background: Pediatric functional gastrointestinal disorders (FGIDs) affect over 1 in 5 children and are associated with chronic mental health conditions and rising pediatric hospitalization, making them a growing concern in pediatric public health. Although they demonstrate high prevalence and persistence into adulthood, early-life risk factors remain under-characterized. A child’s first three years of life represent a critical window for gut microbiome maturation, yet the long-term impact of viral versus bacterial gastroenteritis during this period on subsequent FGID development during childhood is yet to be thoroughly explored.

Methods: Our retrospective cohort study leveraged the TriNetX national research network encompassing a large-scale, real-world pediatric dataset across 135 healthcare organizations to investigate early life acute gastroenteritis during the microbiome’s formative period. We compared the impact of common childhood viral (rotavirus, norovirus, adenovirus, astrovirus) and bacterial (ETEC, EIEC, EPEC, EHEC, Campylobacter jejuni, Clostridioides difficile, and others) pathogens on the subsequent development of FGIDs using ICD-10 codes. We defined our index event as the first documented gastroenteritis episode between ages 0–3. Patients with factors such as prior FGIDs, family history of GI disorders, congenital anomalies, or celiac disease were excluded to reduce confounding. Propensity score matching (PSM) was applied for age at index event, sex, and race. Relative risk ratios (RR) were calculated post-PSM to compare FGID risk between viral and bacterial cohorts, from ages 3 to 18 based on infectious etiology.

Results: Of our two propensity score matched cohorts comprising 15,178 pediatric patients each, acute bacterial gastroenteritis emerges as a significant event while young microbiomes are susceptible to perturbation by pathogens, with marked increase the risk of FGID development. In greater detail, dyspepsia was more than twice as common in the bacterial cohort (1.118%) compared to the viral cohort (0.45%) (RR=0.402; p< 0.0001), suggesting bacterial infections may drive persistent GI dysfunction. Similar trends were observed for IBS (RR=0.213; p< 0.0001) and generalized abdominal pain (RR=0.622; p< 0.0001), supporting the hypothesis that bacterial infections of the gut provoke stronger immune responses leading to increased incidence of dysbiosis and microbiota imbalance. These findings underscore the need for adequate treatment and targeted follow-up of children experiencing a bacterial-type gastroenteritis as well as prevention strategies to mitigate long-term gastrointestinal sequelae.

Conclusion: Understanding the long-term impact of early-life infections on gut health is critical for informing preventive strategies in pediatrics. This study highlights the need for early-life exposures to be considered in FGID risk assessments and supports ongoing public health research into the microbiome's role in chronic pediatric conditions.