Global epidemiology of atopic dermatitis: a comprehensive systematic analysis and modelling study

Epidemiological data on atopic dermatitis (AD) are lacking in 41.5% of countries worldwide. Incidence varies substantially with the location and age of surveyed participants. In this study, the global AD prevalence and affected population were estimated to be 2.6% [95% uncertainty interval (UI) 1.9-3.5] and 204.05 million people, respectively. Around 101.27 million adults and 102.78 million children had AD worldwide, corresponding to prevalence rates of 2.0% (1.4-2.6) and 4.0% (95% UI 2.8-5.3), respectively. Females were more likely to suffer from AD than males: the global prevalence of AD in females was 2.8% (95% UI 2.0-3.7) and affected 108.29 million people worldwide, while in males the corresponding estimates were 2.4% (95% UI 1.7-3.3%) and 95.76 million people. Background Atopic dermatitis (AD) is the leading cause of the global burden from skin disease; no study has provided global and country-specific epidemiological estimates of AD.Objectives To quantify global, regional and country-specific estimates of the epidemiology of AD.Methods A comprehensive search for epidemiological studies in AD was conducted in four electronic databases (PubMed, Embase, Web of Science and China National Knowledge Infrastructure). A Bayesian hierarchical linear mixed model was constructed to calculate epidemiological estimates of AD considering the heterogeneity of regions, countries, type of diagnoses and age strata.Results In total, 344 studies met the inclusion criteria. Incidence varied substantially with the location and age of the surveyed participants. The global prevalence of AD and the population affected by AD were estimated to be 2.6% [95% uncertainty interval (UI) 1.9-3.5] and 204.05 million people, respectively. Around 101.27 million adults and 102.78 million children worldwide have AD, corresponding to prevalence rates of 2.0% (95% UI 1.4-2.6) and 4.0% (95% UI 2.8-5.3), respectively. Females were more likely to suffer from AD than males: the global prevalence of AD in females was 2.8% (95% UI 2.0-3.7%) and affected 108.29 million people, while in males the corresponding estimates were 2.4% (95% UI 1.7-3.3%) and 95.76 million people.Conclusions Epidemiological AD data are lacking in 41.5% of countries worldwide. The epidemiology of AD varies substantially with age and sex and is distributed unequally across geographical regions.