Abstract
Functional gastrointestinal disorders (FGIDs) are classified as a combination of persistent gastrointestinal symptoms. The Rome IV criteria can elucidate several factors in the pathogenesis of FGIDs. The frequency of FGIDs can differ between clinical and nonclinical settings and between geographic regions. To determine the global prevalence of FGIDs in neonates and toddlers according to the Rome IV criteria. We included cohort and descriptive observational studies reporting the prevalence of FGIDs according to the Rome IV criteria in children aged 0-48 months. We searched the Medline, Embase, Lilacs, and CENTRAL databases from May 2016 to the present day. Furthermore, unpublished literature was searched to supplement this information. The Strengthening the Reporting of Observational Studies in Epidemiology statement was used to evaluate the risk of bias. A meta-analysis of the proportions was performed using MetaProp in R. The results are reported in forest plots. We identified and analyzed 15 studies comprising 48,325 participants. Six studies were conducted in Europe, three in Latin America, two in North America, and four in Asia. Most participants were 12-48 months old (61.0%) and were recruited from the community. The global prevalence of FGIDs was 22.0% (95% confidence interval, 15-31%). The most common disorder was functional constipation (9.0%), followed by infant regurgitation syndrome (8.0%). Its prevalence was higher in the Americas (28.0%). FGIDs, as defined by the Rome IV criteria, are present in 22% of children, and the most common primary disorder is functional constipation. A higher prevalence of FGIDs has been reported in America.