Abstract 734: History of diabetes is differentially associated with urothelial cancer risk in understudied racial/ethnic groups in the Multiethnic Cohort Study (MEC)
Authors: Bogumil David , Cortessis Victoria , Wilkens Lynne , Setiawan Veronica Wendy , Haiman Christopher , Marchand Loic Le , Maskarinec Gertraud 
Published: June 2022

Abstract
Background: Type 2 diabetes (T2D) is an established risk factor for urothelial cancer (UC), however there is very little data characterizing this association in populations of non-European ancestry. Understanding the relationship between T2DM and UC across multiple populations is important since both risk and severity of each condition differ according to race and ethnicity.
Methods: We estimated the association between T2D and UC among 185,587 MEC participants who were between 45 and 75 years old at enrollment (1993-1996) and from five major racial/ethnic groups (African Americans, Japanese Americans, Native Hawaiians, Latinos, and non-Hispanic whites). T2D status was assessed by self-report at cohort entry. UC cases were identified through linkages to statewide SEER cancer registries. We estimated the association between T2D and UC using Cox regression, adjusting for known confounders (smoking duration, smoking intensity, alcohol consumption, body mass index), stratifying on sex, age, and ethnicity. Using the full model, we assessed heterogeneity of associations by race/ethnicity.
Results: Over a mean of 19 years of follow-up, 2,398 incident UC cases were identified. The prevalence of T2D was highest among African Americans (15.7%), followed by Latinos (15.6%), Native Hawaiians (14.8%), Japanese Americans (10.5%), and non-Hispanic whites (5.9%). The age-standardized UC incidence rates were highest among whites (60/100,000) followed by Japanese Americans (42/100,000), Native Hawaiians (40/100,000), African Americans (37/100,000), and Latinos (29/100,000). Incidence of UC was 1.11 (95% CI: 0.97, 1.26)-fold greater in those who reported a history of T2D, and this association differed between racial-ethnic groups (pheterogeneity=0.04). Estimates of the association between T2D and UC achieved statistical significance among African Americans (HR=1.49; 95% CI: 1.12, 1.98) and Native Hawaiians (HR=1.68; 95% CI: 1.08, 2.60), but not among non-Hispanic whites (HR=1.06; 95% CI: 0.78, 1.43), Latinos (HR=0.96; 95% CI: 0.71, 1.29), or Japanese Americans (HR=0.95; 95% CI: 0.75, 1.21).
Conclusions: In this multiethnic analysis, estimates of the association between T2DM and UC were strongest among African American and Native Hawaiian participants. The apparently stronger associations in these groups may be due to greater severity and/or poorer control of T2DM. African Americans and Native Hawaiians may benefit from targeted interventions to better manage T2D in these populations to reduce risk of UC.
Citation Format: David Bogumil, Victoria Cortessis, Lynne Wilkens, Veronica Wendy Setiawan, Christopher Haiman, Loic Le Marchand, Gertraud Maskarinec. History of diabetes is differentially associated with urothelial cancer risk in understudied racial/ethnic groups in the Multiethnic Cohort Study (MEC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 734.