Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study: baseline characteristics of enrolled subjects

Abstract

Background: The Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study is a prospective evaluation of the natural history impaired glucose regulation.

Design and methods: The eligibility requirements include age 18-65 yr, history of type 2 diabetes in one or both parents, normal fasting plasma glucose (FPG) or normal glucose tolerance, and African-American or Caucasian status. Participants underwent assessments (including dietary and exercise behavior, clinical examination, glucose tolerance, insulin sensitivity, β-cell function, body composition, energy expenditure) during 2.25-5.5 yr of quarterly follow-up. The primary outcome is the occurrence of prediabetes. Baseline data are presented for the 376 enrolled participants. The cohort was also compared with National Health and Nutrition Examination Survey 2007/2008 participants meeting the age and glycemic criteria for the POP-ABC study.

Results: The POP-ABC cohort [mean (±SD) age was 44.2 ± 10.6 yr] was 57.7% African-Americans, 42.3% Caucasians, and 70.7% females; 86% had one parent with diabetes and 14% had both parents affected. Although greater than 70% of the cohort were employed and 75% had more than 13 yr of education, more African-Americans reported incomes less than $20,000 and fewer reported incomes more than $75,000 compared with Caucasians. Compared with Caucasians, African-Americans had a higher body mass index (31.3 ± 7.8 vs. 28.8 ± 7.8 kg/m(2), P = 0.001), a lower FPG (90.0 ± 7.72 vs. 92.2 ± 7.60 mg/dl, P = 0.008), higher glycosylated hemoglobin, lower triglycerides, and similar blood pressure, and homeostasis model assessment of insulin resistance, homeostasis model assessment of β-cell function, high-density lipoprotein, and low-density lipoprotein cholesterol levels. Compared with a cross-section of U.S. subjects (National Health and Nutrition Examination Survey 2007/2008) with normal FPG and normal glucose tolerance, participants in the POP-ABC study had similar lipid profile but were more educated and had higher body mass index, glycosylated hemoglobin, and blood pressure.

Conclusions: The POP-ABC study has successfully enrolled healthy African-American and Caucasian adults with parental type 2 diabetes mellitus. The study will generate novel data on incidence rates and predictors of prediabetes, and clarify the role of race/ethnicity on early dysglycemia.