Association of total and central adiposity measures with fasting insulin in a biracial population of young adults with normal glucose tolerance: the CARDIA study

Objective: To determine the association of computed tomography (CT)-measure d visceral adipose tissue (AT) and other measures of adiposity with fasting insulin in a biracial (African American and Caucasian) study population of young adults. Research Methods and Procedures: The study population consisted of 251 youn g adults with normal glucose tolerance (NGT), ages 28-40 years, who were Vo lunteers from the Birmingham, Alabama, and Oakland, California centers of t he Coronary Artery Risk Development in Young Adults (CARDIA) study. Results: In regression models with total adiposity measures (body mass inde x or dual-energy X-ray absorptiometry-measured percent fat), visceral AT (m easured as a cross-sectional area in cm(2)) was generally a stronger predic tor of insulin than overall adiposity in all race/gender groups (partial co rrelation coefficients ranging from 0.31 to 0.47) except for black men, in whom the associations were nonsignificant. Partial correlation coefficients between waist circumference and insulin, controlling for percent fat, were nearly identical to those between visceral AT and insulin in women and in white men. Analyses performed on 2060 NGT CARDIA subjects who were not in t his study of visceral AT showed significant correlations of waist circumfer ence with insulin in all race/gender groups, including black men, and that black men in the visceral AT study group were significantly leaner than oth er black male CARDIA subjects. Discussion: We conclude that visceral AT was associated with fasting insuli n in NGT participants in three of the four race/gender groups (black men ex cepted) and that waist circumference was a good surrogate for visceral AT i n examining associations of central adiposity with fasting insulin.