Global, regional, and national burden of thyroid cancer in working-age population: A systematic analysis for the Global Burden of Disease Study 2021.

Objective: This study aims to estimate the thyroid cancer (TC) burden and trends from 1990 and 2021 among working-age population (WAP), at the global, regional, and national levels. Methods: Based on the Global Burden of Disease 2021 study, this cross-sectional study included data on TC incidence and mortality for WAP aged 15-64 years across 204 countries and territories from 1990 to 2021. The age-standardized incidence rate (ASIR) and age-standardized mortality rate (ASMR) of TC were used to estimate the disease burden. Temporal trends of ASIR and ASMR were estimated by average annual percentage changes (AAPCs) based on age-period-cohort models. Relative inequality of TC burden across 204 countries was estimated by the slope index of concentration index. Results: Globally, ASIR of TC increased from 2.27 per 100,000 population to 3.41 per 100,000 population from 1990 to 2021, with AAPC of 1.59% [95% confidence interval (95% CI): 1.54, 1.64]; in contrast, ASMRs were stable at 0.31 per 100,000 population. Females had a higher disease burden than males, and adults aged 45-64 years accounted for more than 55% of the TC cases. Across regions and countries, North Africa and Comoros experienced the highest increase in ASIR, with AAPCs of 2.97% and 7.73%, respectively. All socio-demographic index (SDI) regions experienced a significant increase in ASIR, and regions with high and high-middle SDI experienced a significant decrease in ASMR. Global ASIR burden and ASMR burden were revealed to be concentrated mainly in higher-SDI and lower-SDI countries, respectively, with the concentration index in both sexes of 0.16 (95% CI: 0.13, 0.19) and -0.14 (95% CI: -0.18, -0.10) in 2021. Conclusions: Over the past three decades, the incidence burden of TC among the global WAP remarkably increased. International and regional policies for TC controls are supposed to be updated timely, to handle the current increasing burden and geographic disparities among WAP.