based Diabetes Heart Study (28) were included in this study. All subjects from cohorts 1–5 were recruited in North Carolina, South Carolina, Georgia, Tennessee, or Virginia. The Insulin Resistance Atherosclerosis (IRAS) Studies cohort (cohort 6) consisted of subjects recruited from two multicenter community-based cohort studies, the IRAS Study (29) and the IRAS Family Study (30), designed to examine the epidemiology and genetics of glucose homeostasis traits, respectively. Among these, 575 related subjects from 42 families of the IRAS Family Study recruited from Los Angeles, CA and 278 unrelated subjects from the IRAS study recruited from Los Angeles and Oakland, CA were included in this study.
