Background Onychomycosis is a common fungal nail infection worldwide; however, comprehensive data on global prevalence, causative pathogens, risk factors and socioeconomic distribution remain limited. This study examines these aspects globally to inform clinical practice. Methods This systematic review, registered on PROSPERO and following Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analyses of Observational Studies in Epidemiology guidelines, searched Scopus, PubMed and EMBASE for English-language studies published from January 2013 to September 2023 reporting on onychomycosis prevalence. A random-effects model estimated global prevalence, with meta-regression and subgroup analyses by study setting, region, income level, demographics and fungal species. Results Of 4961 studies, 219 were included. The pooled prevalence among tested samples was 22.91% (95% CI 20.32% to 25.60%). Laboratory-based, medical centre-based or hospital-based studies showed higher prevalence (24.19%; 95% CI 20.99% to 27.54%) compared with community-based studies (8.57%; 95% CI 6.77% to 10.55%). Prevalence was highest in Southeast Asia (42.99%) and lowest in West Asia (16.15%). High-income countries exhibited a prevalence of 25.90%, compared with 17.76% in low-income countries. Prevalence was comparable for men (31.54%) and women (30.05%), peaking at ages 41–50 years (25.05%). Higher prevalence was observed among individuals with metabolic disorders (53.96%) and occlusive footwear users (44.17%). Dermatophytes predominated (53.03%), followed by non-dermatophyte moulds (22.30%) and yeasts (22.12%), with regional differences. Conclusions Onychomycosis represents a considerable global health burden that varies by study setting, geographic region and socioeconomic factors. Given the low to very low certainty of evidence primarily from healthcare settings, these findings underscore the need for more community-based epidemiological research and the importance of targeted prevention and effective management strategies. PROSPERO registration number CRD42024501728.
Wongyikul et al. (Thu,) studied this question.