6893 The Interaction Effect Between BMI, Diabetes, and Age at Diabetes Onset on the Risk of Thyroid Cancer: A Population-Based Cohort Study

Abstract Disclosure: T. Hou: None. Y. Li: None. J. Tian: None. Z. Bloomgarden: None. Y. Shi: None. ObjectiveThe relationship between type 2 diabetes mellitus (T2DM) and thyroid cancer was confounded by some characteristics of diabetes. We aimed to determine the association of the presence of diabetes and, among persons with diabetes, the age at T2DM onset, BMI, and the interactive effect with the subsequent thyroid cancer risk. MethodsWe conducted a population-based longitudinal cohort study including 428,568 persons with new-onset T2DM matched with the general population (100,649,346 person-years). Risk of thyroid cancer by subgroups were calculated based on standardized incidence ratio (SIR), hazard ratio (HR), and Cox proportional hazards models. ResultsIn T2DM patients, 1142 thyroid cancer cases were identified during eight years of follow-up, with an incidence rate of 59.01/100,000 person-years and a higher SIR: 1.21 (95% CI: 1.14-1.28) compared to the general population. New-onset T2DM had an overall 21% higher risk of thyroid cancer. Both the earlier age at T2DM onset and higher BMI were associated with a significant increasing risk of thyroid cancer independently (T2DM onset age <50: SIR 1.46 (1.27-1.69); BMI ≥30.0 Kg/m2 SIR: 1.93 (1.57-2.38)). The highest risk of cancer appeared in the patients with both BMI ≥30.0 Kg/m2 and T2DM onset age <50 years (SIR=3.91, HR=3.04). Among patients with T2DM onset age <60 years, SIR shows an increasing trend of cancer risk with higher BMI levels, while no significant increasing trends with higher BMI in T2DM onset age ≥60 years. For patients with BMI ≥25.0 Kg/m2, SIR of cancer risk decreases with an later T2DM onset age, whereas no significant decreasing trends of cancer risk in BMI <24.9 Kg/m2 group. Obese (BMI ≥30.0 Kg/m2) patients had a significant higher HR of thyroid cancer only when T2DM onset age <60 years. ConclusionsBoth earlier age of T2DM onset (<50 years) and higher BMI (≥30 Kg/m2) contributed to higher risk of thyroid cancer. These results suggest that earlier screening of thyroid cancer might be appropriate in patients diagnosed with T2DM, especially in individuals with young-onset T2DM and obesity. Presentation: 6/3/2024