Racial Disparity in Glucagon-Like Peptide 1 and Inflammation Markers Among Severely Obese Adolescents

Abstract

OBJECTIVE—Compared with Caucasians, obese African-American adolescents have a higher risk for type 2 diabetes. Subclinical inflammation and reduced glucagon-like peptide 1 (GLP-1) concentration are linked to the pathogenesis of the disease. We determined the relationship between insulin resistance, β-cell activity, and subclinical inflammation with GLP-1 concentrations and whether racial disparities in GLP-1 response were present in 49 obese adolescents (14 ± 3 years; 76% African American; 71% female). RESEARCH DESIGN AND METHODS—Subjects underwent physical examination and an oral glucose tolerance test. We measured levels of high-sensitivity CRP (CRPhs), fibrinogen, glucose, GLP-1total, GLP-1active, and insulin. Insulin and glucose area under the curve (AUC), insulinogenic index (ΔI30/ΔG30), and composite insulin sensitivity index (CISI) were computed. Subjects were categorized by race and as inflammation positive (INF+) if CRPhs or fibrinogen were elevated. RESULTS—No racial differences were seen in mean or relative BMI. Thirty-five percent of subjects had altered fasting or 2-h glucose levels (African American vs. Caucasian, NS), and 75% were INF+ (African American vs. Caucasian, P = 0.046). Glucose and insulin, CISI, and ΔI30/ΔG30 values were similar; African Americans had lower GLP-1total AUC (P = 0.01), GLP-1active at 15 min (P = 0.03), and GLP-1active AUC (P = 0.06) and higher fibrinogen (P = 0.01) and CRPhs (NS) compared with Caucasians. CONCLUSIONS—African Americans exhibited lower GLP-1 concentrations and increased inflammatory response. Both mechanisms may act synergistically to enhance the predisposition of obese African Americans to type 2 diabetes. Our findings might be relevant to effective deployment of emerging GLP-1–based treatments across ethnicities.