FAT DISTRIBUTION AND INSULIN-RESPONSE IN PREPUBERTAL AFRICAN-AMERICANAND WHITE-CHILDREN

Ethnic differences in obesity-related disease prevalence may relate to differences in fat distribution or metabolism. We conducted a study i n 73 African Americans and white children to examine the relation betw een fat distribution and insulin and to determine whether ethnic diffe rences in fat distribution or in adiposity-insulin relations contribut e to differences in insulin concentrations. Fasting and postchallenge insulin concentrations were determined by oral-glocose-tolerance test, total body fat by dual-energy X-ray absorptiometry, and subcutaneous abdominal (SAAT) and intraabdominal (IAAT) adipose tissue by computeri zed tomography. African Americans had greater fasting insulin (X &PLUS MN; SD: 79&PLUSMN; 37 compared with 55&PLUSMN; 23 pmol/L,P<0.01), incr emental 30-min insulin (567&PLUSMN; 438 compared with 300&PLUSMN; 304 pmol/L,P<0.01). In multiple linear regression, fating insulin was inde pendently related to total fat within both ethnic groups (model R-2=0. 42 and 0.52 for African Americans and whites, respectively), increment al 30-min insulin to total fat and IAAT in whites only (model R-2=0.71 ), and AUC to SAAT in African Americans only (model R-2=0.49). Adjusti ng insulin indexes for adiposity did note eliminate the significant ef fect of ethnicity. In general, relations between adiposity and insulin were stronger in whites than in African Americans. African American c hildren had higher insulin concentrations than white children after to tal body fat, IAAT, and SAAT were controlled for. However, strong rela tions between adiposity (total and abdominal) and insulin in both grou ps suggest that obesity may contribute to disease risk regardless of e thnicity.