Global Burden of Alopecia Areata and Associated Diseases: A Trend Analysis From 1990 to 2021

Alopecia areata (AA) is a chronic autoimmune disorder characterized by non-scarring hair loss, affecting approximately 2% of the global population. Its etiology involves genetic, immunological, and environmental factors, with significant psychological impacts such as anxiety and depression. However, international trends and comorbidity associations remain poorly understood.

This study aims to analyze global trends in the incidence and prevalence of AA and assess its associations with major comorbidities across different demographic and regional groups.

Using data from the Global Burden of Disease Study (GBD) 2021, AA incidence, prevalence, and years lived with disability (YLDs) from 1990 to 2021 were analyzed by age, sex, geographic region, and socioeconomic indices (SDI and HDI). Temporal trends were evaluated with Pearson's correlation and Joinpoint regression, and comorbidities were assessed against 22 conditions.

From 1990 to 2021, global AA incidence increased in absolute terms, though age-standardized incidence rates (ASIR) slightly declined. Incidence was highest in North America, Southeast Asia, and Australia, with females and individuals aged 30-34 most affected. Significant associations were found with atopic dermatitis, iron deficiency, and depressive disorders, with regional variations in comorbidity patterns.

This study highlights rising AA cases with stable ASIRs, reflecting improved awareness and reporting. Findings underscore the complex interplay of socioeconomic factors, healthcare access, and AA burden. Further research should investigate mechanisms underlying comorbidities and guide targeted interventions to mitigate the physical and psychological impacts of AA.