Global pattern, trend, and cross-country health inequality of adult acne aged 25 + years from 1990 to 2021, a comprehensive analysis for global burden of disease and global dietary database

The epidemiology and burden of adult acne have not been comprehensively evaluated. This study aims to analyze the global disease burden of adult acne from 1990 to 2021 and explore potential risk factors. With Global Burden of Disease (GBD), we got all the incidence, prevalence, disability-adjusted life years (DALYs), and corresponding age-standardised rate (ASR) of acne vulgaris (25 + years). The data were stratified by three dimensions of distribution and the Socio-Demographic Index (SDI). We calculated the estimated annual percentage change (EAPC) to evaluate trends, and assessed health inequality, then employed Bayesian age-period-cohort (BAPC) analysis for forecasting. Mendelian Randomization (MR) analysis was utilized for identifying potential risk factors, the Global Dietary Database (GDD) for verification. From 1990 to 2021, global incidence of adult acne cases increased by 66.6%, reaching 20,290,350 (95% UI: 19,253,788-21,344,142); prevalence rose by 66.4%; DALYs' by 66.2%. Projections suggest continued increases through 2030. Although the global ASRs began to decline in the twenty-first century, the lower SDI regions showed a contrasting upward trend. In all regions, the greatest increases in the EAPC of ASRs were observed in Western Sub-Saharan Afric, whereas the largest declines occurred in the High-Income Asia Pacific region,1990-2021. A negative correlation was found between the ASR of adult acne and countries' SDIs (p < 0.01). Notably, females experienced a higher burden of adult acne than males in various dimensions. MR results suggested that intake of sugar added to coffee is associated with an increased incidence of acne, consistent with the findings of the relationship between sugar-sweetened beverage (SSB) intakes and the ASR of adult acne across countries. The disease burden of adult acne demonstrates significant heterogeneity across regions and genders, with obviously greater severity in underdeveloped areas and among females. Meanwhile, it should pay attention to the parallel issue of nutritional inequality.