USA: Higher C-reactive protein (CRP) is a risk factor for incident diabetes, states a recent study, however, the excess diabetes burden in Black adults was observed only in those having lower CRP. This suggests inflammation is not likely to be the main driver of this racial disparity. The study was published in the Journal of Clinical Endocrinology & Metabolism on 08 February 2022.
Black adults compared to White adults have been shown to experience more type 2 diabetes mellitus (T2DM) ansl also high inflammatory markers including CRP. Inflammatory markers are linked with incident diabetes risk but the impact of inflammation on racial differences in incident diabetes is not known. To fill this knowdlge gap, Timothy B Plante, Larner College of Medicine at the University of Vermont, Burlington, VT, and colleagues aimed to assess whether CRP mediated the Black-White incident diabetes disparity in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study.
The study enrolled 30,239 US Black and White adults aged ≥45 years in 2003-2007 with a second visit approximately 10-years later. In participants without baseline baseline diabetes, adjusted sex- and race-stratified risk ratios (RR) for incident diabetes at the second visit by CRP level were calculated. The percent mediation of the racial disparity by CRP was estimated by inverse odds weighting.
Based on the study, the researchers found the following:
Of 11,073 participants without baseline diabetes (33% Black, 67% White), 1,389 (12.5%) developed diabetes.
Black participants had higher CRP at baseline and greater incident diabetes than White participants.
Relative to CRP <3 mg/L, CRP ≥3 mg/L was associated with greater risk of diabetes in all race-sex strata.
Black participants had higher risk of diabetes at CRP <3 mg/L, but not at CRP ≥3mg/L.
In women, CRP mediated 10.0% of the racial difference in incident diabetes. This mediation was not seen in men.
To conclude, higher CRP is a risk factor for incident diabetes, but the excess diabetes burden in Black adults was only seen in those with lower CRP. This implies that inflammation is unlikely to be the main driver of this racial disparity, the researchers wrote.
Reference:
Kaitlyn M Peper, BS, Boyi Guo, MS, D Leann Long, PhD, George Howard, DrPH, April P Carson, PhD MSPH, Virginia J Howard, PhD MSPH, Suzanne E Judd, PhD MPH, Neil A Zakai, MD MSc, Andrea Cherrington, MD MPH, Mary Cushman, MD MSc, Timothy B Plante, MD MHS, C-reactive protein and racial differences in type 2 diabetes incidence: The REGARDS study, The Journal of Clinical Endocrinology & Metabolism, 2022;, dgac074, https://doi.org/10.1210/clinem/dgac074