Abstract B131: Association between type 2 diabetes and prevalence of monoclonal gammopathy of undetermined significance in a large screened U.S. population

Abstract Introduction: Monoclonal gammopathy of undetermined significance (MGUS) is a benign clone of plasma cells and a necessary precursor to multiple myeloma (MM) — a rare and fatal cancer of the blood that is 2-3 times more common in Black men and women than non-Hispanic White individuals. MGUS prevalence is also higher in Black men and women; therefore, the racial disparity in MGUS prevalence likely drives the disparity observed in MM incidence. Inflammatory processes may influence MGUS/MM, but few previous studies have evaluated the possible association between type 2 diabetes (T2D) and MGUS in a multi-racial population. This study evaluates the association between T2D and MGUS among participants in three large cohorts: the Black Women’s Health Study (BWHS), the Multiethnic Cohort (MEC), and the Southern Community Cohort Study (SCCS). Methods: In the BWHS (n=3,801), participants aged 50-79 years were randomly selected for MGUS screening. In the MEC (n=1,289) and SCCS (n=2,986), participants were efficiently selected using the Medicare MGUS billing code and laboratory validation in serum. MGUS case status was defined as detection of a paraprotein <3 g/dL in serum by serum protein electrophoresis (SPEP) with reflex to immunofixation for positive or equivocal SPEP among participants with archived blood samples. History of T2D before blood draw was based on self-report of a physician diagnosis or use of medication for T2D. We pooled and harmonized data and used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between T2D and MGUS, adjusting for age, sex, race/ethnicity, and body mass index (BMI); cohort was adjusted for in separate models. We also evaluated the relationship between treated and untreated T2D with MGUS prevalence. Lastly, we evaluated this association within strata of BMI at blood draw (<30 vs. ≥30 kg/m2 ). Results: Our analysis included 916 MGUS cases and 7,160 non-cases. ORs comparing a history of T2D to no diabetes were 0.75 (95% CI 0.63, 0.90) in age- and sex-adjusted models and 0.76 (95% CI 0.63, 0.92) in models additionally adjusted for BMI and race/ethnicity. Multivariable-adjusted ORs for T2D treated with metformin, other medications, or untreated compared to no diabetes were 0.71 (95% CI 0.53, 0.94), 0.80 (95% CI 0.61, 1.06), and 0.79 (95% CI 0.57, 1.10), respectively. Restricting to participants with a history of T2D, ORs for types of T2D treatment were 0.92 (metformin; 95% CI 0.61, 1.39) and 1.25 (other treatment; 95% CI 0.80, 1.93). Further adjustment for cohort resulted in attenuated estimates (OR: 0.90, 95% CI 0.74, 1.09). Inverse results were observed within strata of BMI. Conclusions: In contrast to our hypothesis, these preliminary findings do not provide evidence that T2D is associated with a higher prevalence of MGUS, regardless of whether T2D was treated with medication or not. Future work will include a fourth cohort, the Women’s Health Initiative. Citation Format: Etienne X. Holder, Mallory Bernstein, Jia Wan, Esther A. Lam, Jane Emerson, Yatchana Kataria, Gary Zirpoli, Sabrina Racine-Brzostek, Christopher A. Haiman, Qiuyin Cai, Alexander Reiner, Julie R. Palmer, Pinkal Desai, Wendy Cozen, Kimberly A. Bertrand. Association between type 2 diabetes and prevalence of monoclonal gammopathy of undetermined significance in a large screened U.S. population [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr B131.