Global epidemiology of thyroid cancer: trends in incidence, mortality, and DALYs from 1990 to 2021

Objectives: This study provides the first comprehensive assessment of the global thyroid cancer burden from 1990 to 2021, focusing on incidence, mortality, and DALYs trends across 204 countries. Methods: Using Global Burden of Disease (GBD) 2021 data, age-standardized rates (ASRs) and estimated annual percentage changes (EAPCs) were calculated. Associations with the Socio-demographic Index (SDI) were analyzed via linear regression. Results: Globally, the age-standardized incidence rate increased from 2.06 to 2.91 per 100,000 (EAPC=1.25), with women accounting for 67 % of cases. Mortality showed a modest decline (EAPC=-0.23), but DALYs remained high (14.57 million in 2021). High-SDI regions, such as North America, accounted for 72 % of cases, reflecting intensive screening, whereas low-SDI regions, particularly Sub-Saharan Africa, contributed 68 % of deaths due to delayed diagnosis. High BMI contributed 1.68 % of DALYs, peaking at 4.26 % in Andean Latin America. Incidence varied significantly across countries, from 7.13 per 100,000 in Saudi Arabia (linked to iodine excess) to 0.014 per 100,000 in Tajikistan (iodine deficiency). Mortality was highest among elderly males, reaching 12.57 per 100,000 in those aged ≥90 years. Conclusions: The rising global burden of thyroid cancer highlights pronounced gender and regional disparities. High-SDI regions should prioritize risk-stratified strategies to reduce overdiagnosis, while low-SDI regions require improved access to healthcare. Targeted efforts in early detection and metabolic risk reduction are critical to mitigate disease burden.