LOW INSULIN-SECRETION AND HIGH FASTING INSULIN AND C-PEPTIDE LEVELS PREDICT INCREASED VISCERAL ADIPOSITY - 5-YEAR FOLLOW-UP AMONG INITIALLYNONDIABETIC JAPANESE-AMERICAN MEN

Insulin resistance and hyperinsulinemia occur more frequently in subje cts with greater visceral adiposity, but it is not known whether these metabolic abnormalities precede or follow visceral fat accumulation, We prospectively studied the development of visceral adiposity in rela tion to fasting and stimulated insulin and C-peptide levels, We follow ed 137 nondiabetic, second-generation Japanese-American men for change s in visceral adiposity over 5 years, Intra-abdominal fat (IAF) area ( square centimeters) was measured at the umbilicus by computed tomograp hy at baseline and after 5 years, Plasma insulin and C-peptide levels were measured after an overnight fast and during an oral glucose toler ance test. beta-cell function was measured by the insulin secretion ra tio (30-0 min plasma insulin difference)/(30-0 min plasma glucose diff erence), After adjustment for baseline IAF in multiple linear regressi on models, baseline fasting insulin (coefficient = 0.241, P = 0.048) a nd C-peptide (coefficient 38.538, P < 0.001) levels were positively co rrelated, while the baseline insulin secretion ratio was negatively co rrelated with IAF change (coefficient -0.099, P = 0.027), With lAF dif ference coded as a dichotomous variable (>0 cm(2) vs, less than or equ al to 0 cm(2)), the highest versus lowest tertile of baseline fasting insulin (odds ratio [OR] = 3.0, 95% CI 1.0-9.7) and fasting C-peptide (OR = 8.1, 95% CI 2.4-26.8) levels and the lowest versus highest terti le of the insulin secretion ratio (OR = 3.3, 95% CI 1.0-10.0) were ass ociated with higher odds of IAF gain, Greater insulin resistance and r educed insulin secretion precede visceral fat accumulation in nondiabe tic Japanese-American men.