Diabetes and cancer incidence among adults in the Hispanic Community Health Study/Study of Latinos

Background: Diabetes is associated with an increased risk of cancer; however, few epidemiological studies of diabetes and cancer risk have focused on Hispanic/Latino adults. This study examined the associations between three time-varying measures of diabetes and cancer incidence among participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Methods: HCHS/SOL is a multi-site prospective cohort study of 16,415 Hispanic/Latino adults. Time-varying diabetes measures (assessed at visit 1: 2008–2011 and visit 2: 2014–2017) included diabetes status (no diabetes, pre-diabetes, and diabetes), glycemic control (no diabetes, pre-diabetes, controlled diabetes [hemoglobin A_1c (HbA_1c) <7.0%], and uncontrolled diabetes [HbA_1c ≥7.0%]), and insulin resistance (no diabetes, pre-diabetes + Homeostatic Model Assessment of Insulin Resistance [HOMA-IR] <3.0, pre-diabetes + HOMA-IR ≥3.0, diabetes + HOMA-IR <3.0, and diabetes + HOMA-IR ≥3.0). Incident cancers diagnosed from visit 1 through 2021 were identified through state cancer registry linkages; 715 cancers including 330 obesity-related cancers (ORCs) were diagnosed over a mean follow-up of 10.7 years. The authors used survey-weighted marginal structural Cox regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for each time-varying diabetes measure and overall cancer and ORC risk, adjusting for demographic, social, and behavioral characteristics. Results: Time-varying pre-diabetes and diabetes (vs. no diabetes) status were associated with cancer HRs of 1.82 (95% CI, 1.27–2.61) and 2.49 (95% CI, 1.65–3.74), respectively. HRs were further elevated among those with diabetes + HbA_1c ≥7.0% (HR, 3.12; 95% CI, 1.44–6.79) and those with diabetes + HOMA-IR ≥3.0 (HR, 2.78; 95% CI, 1.69–4.56). Associations were stronger for ORC risk; however, estimates were less precise. Conclusion: Diabetes is associated with increased risk of cancer and ORC. Diabetes prevention and control may be additionally important for cancer prevention among Hispanic/Latino adults.