Associations of Type 2 Diabetes with risk of overall and site-specific cancers in a cohort of predominantly low-income racially diverse populations

Abstract Background: The prevalence of type 2 diabetes (T2D) is higher in Black than white Americans, and individuals with T2D have an increased cancer risk. We investigated the association of T2D with the risk of all cancer combined and 21 site-specific cancers, among predominantly low-income participants who experienced a disproportionately high risk of both T2D and cancer. Methods: The study included 76,121 participants (mean age: 52.0 years; 67.2% Black) from the Southern Community Cohort Study (SCCS). T2D was ascertained at the baseline survey. Incident cancer was ascertained via linkage to state cancer registries. Cox proportional hazard models were used to estimate the associations between T2D and cancer after adjusting for confounders. Results: Among participants, 21.2% (N=16,137) had baseline T2D, and 9.7% (N=7,376) were diagnosed with incident cancer. Compared to individuals without T2D, individuals with T2D had a significantly elevated risk of all cancer combined (HR: 1.07; 95% CI: 1.01-1.13) and several site-specific cancers, including cancers of the stomach, colorectum, pancreas, liver/intrahepatic bile duct, kidney, and renal pelvis as well as leukemia. The significant association for most cancers was largely observed within 15 years after T2D diagnosis, except for cancer of the pancreas and liver/intrahepatic bile duct, for which elevated risks remain statistically significant 15 to 30 years after T2D diagnosis Conclusion: T2D was associated with the risk of overall and certain site-specific cancers in this predominant low-income population. Impact: Preventive measures to reduce the burden from T2D could help reduce the risk of overall cancer and several site-specific cancers.