Microvascular Complications and Cancer Risk in Type 2 Diabetes: A Population-Based Study

Background: Microvascular complications in type 2 diabetes (T2D) and cancer share biological pathways, including chronic inflammation, dysregulated angiogenesis, and endothelial dysfunction, yet their impact on cancer risk and mortality remains unclear. This study evaluated whether T2D patients with microvascular complications face increased cancer incidence or cancer-related mortality. Methods: Using the Taiwan National Health Insurance Research Database, we identified individuals newly diagnosed with T2D (2008-2021) and assessed the outcomes with multivariable Cox proportional hazards models. Results: Our findings indicate that T2D patients with diabetic neuropathy, retinopathy, or chronic kidney disease do not have a significantly increased risk of major cancers, including those of the oral cavity, thyroid, breast, respiratory tract, digestive system, or lymphoid tissues. Similarly, microvascular complications were not associated with higher cancer-related mortality. However, microvascular complications significantly increased all-cause mortality in a dose-dependent manner: adjusted hazard ratio (aHR) 1.16 [95% CI: 1.15-1.17] for one complication, aHR 1.42 [1.38-1.45] for two, and aHR 1.71 [1.60-1.83] for three. Conclusions: In this nationwide cohort study, we demonstrate that while microvascular complications are associated with increased all-cause mortality in T2D, they do not appear to elevate cancer risk or cancer-specific mortality. These findings provide crucial epidemiological insights into the relationship between diabetes complications and cancer.