Global Prevalence of Functional Constipation Across All Age Groups According to Rome II–IV Criteria, 1999–2025: A Systematic Review and Meta-Analysis

INTRODUCTION: The most recent global estimates of functional constipation (FC) were reported in 2020 for adults and in 2017 for children; however, no comprehensive update encompassing all age groups has been published since then. Thus, we aimed to provide an updated, standardized global estimate of FC prevalence across all age groups using the Rome criteria. METHODS: We systematically searched PubMed/MEDLINE, Embase, CINAHL, and Cochrane Library, from inception to March 28, 2025, for population-based observational studies reporting FC prevalence according to Rome II, III, or IV criteria. Eligible studies included cross-sectional or prospective designs involving children, adults, or older population. Studies without Rome-based definitions, extractable prevalence data, or population-based sampling were excluded. The primary outcome was pooled prevalence of FC. Subgroup analyses were performed by Rome version, diagnostic method, geographic region, age, sex, and behavioral factors. RESULTS: From 12,574 identified records, a total of 128 studies from 44 countries comprising 459,061 participants met inclusion criteria. The global pooled prevalence of FC was 12.14% (95% CI, 11.14-13.23; I 2 = 98.99%). Prevalence was higher in female patients (14.60% [12.50-17.04]; I 2 = 99.01%) than male patients (10.62% [8.84-12.75]; I 2 = 98.74%). By age, prevalence was highest in older population (19.89% [95% CI, 14.67-26.97]; I 2 = 98.77%), followed by children (12.06% [11.05-13.16]; I 2 = 97.85%) and adults (9.50% [8.11-11.14]; I 2 = 99.12%). The pooled prevalence was highest with Rome II (12.68% [95% CI, 8.02-20.04]; I 2 = 99.31%) and lowest with Rome IV (10.34% [9.11-11.75]; I 2 = 98.79%). DISCUSSION: FC is a highly prevalent global disorder, with substantial variation by age, sex, diagnostic criteria, country, and region. Standardized population-based assessments using validated Rome criteria are essential to inform clinical practice and public health strategies.