Global trends and modifiable risk factors for atopic dermatitis incidence: Insights from GBD 2021.

Background: Global patterns in atopic dermatitis (AD) incidence and their associations with modifiable risk factors remain unclear.

Objective: We sought to analyze global trends in AD incidence and identify associated socioeconomic, environmental, and lifestyle factors contributing to its global disparities and epidemics.

Methods: Data on AD in 204 countries and territories from 1990 to 2021 were extracted from the Global Burden of Diseases Study 2021. Age-standardized incidence rates (ASIRs) were calculated by sex and region. Socioeconomic development was measured by the Sociodemographic Index, a composite indicator of income, education, and fertility. Modifiable risk factors-including high body mass index, low physical activity, air pollution, and unhealthy diets-were quantified using summary exposure values, reflecting the population-level exposure to each risk. Dietary risks included diet high in sugar-sweetened beverages, processed meat, and sodium, and low intake of whole grains. Relationships between ASIRs and summary exposure values were independently assessed using restricted cubic spline regression.

Results: In 2021, 16.0 million new cases of AD were recorded globally, with the highest ASIRs in high-income Asia Pacific (474.8 per 100,000 population) and Western Europe (421.7 per 100,000 population) geographically and higher ASIRs in women. AD incidence strongly increased with socioeconomic development. Among modifiable risk factors, high body mass index, low physical activity, and nitrogen dioxide pollution formed positive associations with AD risk. Diets rich in sugar-sweetened beverages, processed meat, and sodium and diet low in whole grains further increased the risk.

Conclusions: Global disparities in AD incidence trends are closely linked to socioeconomic development and modifiable risk factors, including obesity, air pollution, and unhealthy diets. Addressing these factors through targeted public health policies is essential to mitigating the global burden of AD, particularly in industrialized and rapidly developing regions.