Epidemiology of functional gastrointestinal disorders in children and adolescents: A systematic review.

AIM: To assess the prevalence of functional gastrointestinal disorders (FGIDs) in children and adolescents.

METHODS: PubMed, EMBASE, and Scopus databases were searched for original articles from inception to September 2016. The literature search was made in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. For inclusion, each study had to report epidemiological data on FGIDs in children between 4 and 18 years old and contain standardized outcome based on Rome II, III or IV criteria. The overall quality of included epidemiological studies was evaluated in accordance with Loney's proposal for prevalence studies of health literature. Two reviewers assessed each study for data inclusion and extraction. Discrepancies were reconciled through discussion with seniors.

RESULTS: A total of 659 articles were identified from the databases and 16 through manual search. A total of 43 articles fulfilled the eligibility criteria for full-text reading, with 26 remaining to be included in the final analysis. All studies were written in English and published between 2005 and 2016. Eight (30.8%) articles were performed in North America, five (19.2%) in Latin America, five (19.2%) in Europe, seven (27%) in Asia, and one (3.8%) in Africa. Sample size varied between 114 and 99416 subjects, totaling 132600 individuals. Fourteen (53.9%) studies recruited their target samples from schools, 11 (42.3%) from healthcare settings and the remaining one (3.8%) from online panel community. The overall FGID prevalence rates for student samples ranged from 9.9% to 29% to as high as 87% in clinical samples. Cyclic vomiting, irritable bowel syndrome and functional constipation were the most researched conditions, with a prevalence ranging from 0.2% to 6.2%, 0% to 45.1% and 0.5% to 86.9%, respectively. The qualitative appraisal revealed that most of the studies showed average or below average generalizability.

CONCLUSION: The heterogeneity of the studies on FGIDs must be improved in order to allow comparison. Improvements should include appropriate sampling of representative population, comparable study setting, and consistent data collection.