Prevalence of Anorexia Nervosa in Population-Based Studies: A Systematic Review and Meta-Analysis

Background: Reported prevalence of anorexia nervosa (AN) varies across populations, diagnostic systems, and reference periods. Methods: A systematic review of population-based prevalence studies was conducted using PubMed, Embase, Scopus, Web of Science, PsycINFO, LILACS, and SciELO. Methodological quality was assessed using the nine-domain Joanna Briggs Institute checklist. Compatible adult and adolescent survey estimates were synthesized using random-effects inverse-variance meta-analysis with restricted maximum likelihood estimation and modified Hartung–Knapp confidence intervals. Results: A total of 21,316 records were identified, of which 105 reports met the eligibility criteria. Five publications provided data for four meta-analyses stratified by age group, diagnostic criteria, and prevalence period. Among adults, pooled lifetime prevalence was 0.34% (95% CI < 0.01–43.67%; k = 2) based on DSM-IV criteria and 0.48% (95% CI 0.09–2.44%; k = 3) when a DSM-5 estimate was included. Among adolescents, pooled lifetime prevalence was 0.39% (95% CI 0.01–9.18%; k = 2), whereas 12-month prevalence was 0.19% (95% CI 0.01–4.05%; k = 2). Conclusions: Although the pooled point estimates were low, their substantial uncertainty limits generalization. More consistent ascertainment and reporting of survey-specific precision are needed to improve comparisons across populations.