Global and regional trends in psoriasis burden (1990–2021): age patterns and socio-demographic associations

Psoriasis is a chronic immune-mediated skin disease increasingly recognized as a systemic condition with broad implications for health and quality of life. This study aims to describe global, regional, and national in psoriasis burden from 1990 to 2021 using the Global Burden of Disease (GBD) database, characterize age-group patterns, and examine ecological associations with socio-demographic development. Incidence, prevalence, and disability-adjusted life years (DALYs) were extracted from GBD 2021 for 204 countries and territories. Age- and sex-specific trends were analyzed using joinpoint regression and Bayesian age–period–cohort models in R. The findings indicate substantial global disparities in psoriasis incidence and prevalence as of 2021, with developed nations like Germany reporting the highest rates, while Somalia exhibited the lowest. Psoriasis burden was particularly pronounced in high-income regions and among older populations. Age- and gender-specific analyses indicated that individuals aged 50–69 and over 70 were most severely affected, with middle-aged men exhibiting higher incidence and prevalence than women. Socio-demographic Index (SDI) analysis suggested a positive correlation between psoriasis burden and economic development. Psoriasis burden suggests marked age-pattern concentration and ecological associations with development level. These findings inform public health planning—especially for aging populations—while not quantifying the proportion of change attributable to population aging. Future work using formal decomposition and factor-level socio-demographic analyses is warranted.