Abstract
Objectives: To analyze and compare temporal trends, demographic characteristics, and stage at diagnosis for thyroid cancer (TC) between Saudi and non-Saudi populations in order to identify potential population-specific etiological drivers. Methods: We conducted a national retrospective cohort study of TC cases in Saudi Arabia from 2013–2022. To assess population-level trends, we computed age-standardized incidence rates (ASIRs) and multivariable Poisson regression alongside piecewise regression models for comparative analysis. Results: Among 14,159 total cases, TC incidence increased disproportionately in Saudi nationals, rising from 884 to 1,677 (90%), significantly outpacing the 184 to 275 (49%) increase observed in non-Saudis. The incidence rate ratio for Saudis versus non-Saudis was 5.67 (95% CI [5.41, 5.94]). Saudis presented with a significantly younger median age at diagnosis (5–10 years earlier, p < 0.001) and demonstrated a steeper annual increase in ASIRs (Interaction β = 0.0307, p < 0.001). A marked stage migration was concurrently observed among Saudi nationals, with localized diagnoses increasing from 55% to 71%. The recent period of the study (post-pandemic) revealed an acceleration in the Saudi cohort (+316.50 cases annually), a pattern absent in non-Saudis. Conclusion: The profound divergence in incidence trends provides compelling evidence consistent with distinct, population-specific etiological drivers. This suggests a need to investigate genetic and environmental factors unique to the Saudi population. However, the heterogeneity of the non-Saudi comparator group necessitates cautious interpretation of the observed incidence rates.
Article Type
Original Study
First Page
859
Last Page
868
Recommended Citation
Khamjan, Nizar A.
(2026)
"Ethnic Background as a Determinant of Thyroid Cancer Risk: A Decade-Long National Cohort Study Reveals Divergent Epidemics in Saudi Arabia,"
Saudi Medical Journal: Vol. 47:
Iss.
5, Article 12.
DOI: https://doi.org/10.15537/1658-3175.8770