I WENG YENChien, Jen-ChiehJen-ChiehChienYang, Yu-HsuanYu-HsuanYangTan, Elise Chia-HuiElise Chia-HuiTanHUNG-YUAN LI2025-07-012025-07-012025-06-04https://scholars.lib.ntu.edu.tw/handle/123456789/730423Aims: Insulin is essential for glycemic control in type 1 diabetes but has mitogenic effects that may impact cancer risk. This study examines the relationship between daily insulin dose, cancer incidence, and all-cause mortality to assess its therapeutic benefits and potential risks. Methods: A retrospective cohort study was conducted using Taiwan's National Health Insurance Research Database and Cancer Registry. Patients were categorized by insulin dose percentiles (25th, 50th, 75th) and analyzed using Cox proportional hazards models, adjusting for demographic and clinical factors. Sensitivity analyses were performed using Poisson regression to validate the findings. Results: Among 10,248 patients, higher insulin doses were linked to lower cancer risk (HR = 0.42, 95 % CI: 0.28–0.64) and reduced all-cause mortality (HR = 0.35, 95 % CI: 0.26–0.49). Sensitivity analyses confirmed these findings. Conclusions: Higher insulin doses may protect against cancer and reduce mortality, likely due to improved glycemic control. While insulin's mitogenic effects raise concerns, poor glycemic control itself is a known cancer risk factor. These findings suggest that optimizing insulin therapy in type 1 diabetes may outweigh potential oncogenic risks. Future research should validate these results in broader populations and explore underlying mechanisms to refine insulin dosing strategies for improved long-term outcomes.enIncident cancerInsulinOverall survivalType 1 diabetes[SDGs]SDG3journal article10.1016/j.diabres.2025.11229040480375