National Institute of Diabetes and Digestive and Kidney DiseasesThe Effect of Psychosocial and Physiologic Stress on the Development of β Cell Failure in African Immigrants with Abnormal Glucose Tolerance
Abnormal glucose tolerance (Abnl-GT) combines diabetes and prediabetes into a single term and occurs due to an imbalance between insulin resistance (IR) and β-cell function. In African American individuals, Abnl-GT is most often due to IR-related obesity. However, data emerging from the Africans in America cohort reveals that the majority of African immigrants with Abnl-GT are nonobese and have β-cell-failure. Most nonobese individuals are not identified as “at-risk” – consequently, they are usually diagnosed only after the onset of clinical complications. Hence, preventable disease progression occurs due to late diagnosis of Abnl-GT-β-cell-failure. Yet, knowledge on β-cell-failure as the primary determinant of Abnl-GT is lacking. The psychosocial precipitants, phenotype and optimal tests to detect β-cell-failure in African immigrants are also undetermined. The application of adiponectin and copeptin as markers of β-cell-failure have also never been assessed in African populations.
Working with African immigrants, Dr. Wentzel and her team’s primary goal is to assess the metabolic consequences in the Abnl-GT-β-cell-failure group vs NGT, and to examine and compare the psychosocial and physiological stress precipitants in the Abnl-GT-β-cell-failure group first to the NGT and then to the Abnl-GT-IR group.
Glucose tolerance will be determined by oral glucose tolerance test. Abnl-GT is defined as fasting glucose≥100 mg/dL and/or 2h glucose≥140 mg/dL. Insulin resistance (IR) will be determined by the lowest quartile of the Matsuda index. Abnl-GT-IR requires both Abnl-GT and IR. Abnl-GT-β-cell failure requires Abnl-GT without IR. Psychosocial and physiologic stress measures will include: Cohen Perceived Stress Scale, allostatic load score, acculturation, and sleep quality. Plasma adiponectin and copeptin levels will also be measured.
If the psychosocial and metabolic profiles are worse in Abnl-GT-β-cell-failure than the NGT group, this will reveal a previously unappreciated public health problem. Risk underestimation in the Abnl-GT-β-cell-failure means diagnosis only after the onset of clinical complications. If adiponectin and copeptin prove useful within the context of Abnl-GT-β-cell-failure in African immigrants, their application across African populations could provide diagnostic and mechanistic insight regarding Abnl-GT-β-cell-failure, and the psychosocial stress-linked to β-cell-failure.