Insulin Sensitivity in African‐American and White Women: Association With Inflammation

Abstract

Whether the contribution of inflammation to risk for chronic metabolic disease differs with ethnicity is not known. The objective of this study was to determine: (i) whether ethnic differences exist in markers of inflammation and (ii) whether lower insulin sensitivity among African Americans vs. whites is due to greater inflammatory status. Subjects were African-American (n = 108) and white (n = 105) women, BMI 27-30 kg/m 2 . Insulin sensitivity was assessed with intravenous glucose tolerance test and minimal modeling; fat distribution with computed tomography; body composition with dual-energy X-ray absorptiometry; markers of inflammation (tumor necrosis factor (TNF)-α, soluble tumor necrosis factor receptor (sTNFR)-1, sTNFR-2, C-reactive protein (CRP), and interleukin (IL)-6) with enzymelinked immunosorbent assay (ELISA). Whites had greater intra-abdominal adipose tissue (IAAT), insulin sensitivity, and concentrations of TNF-α, sTNFR-1, and sTNFR-2 than African Americans. Greater TNF-α in whites vs. African Americans was attributed to greater IAAT in whites. Among whites, but not African Americans, CRP was independently and inversely associated with insulin sensitivity, after adjusting for IAAT (r = −0.29 P < 0.05, and r = −0.13 P = 0.53, respectively). Insulin sensitivity remained lower in African Americans after adjusting for CRP (P < 0.001). In conclusion, greater IAAT among whites may be associated with greater inflammation. Insulin sensitivity was lower among African Americans, independent of obesity, fat distribution, and inflammation.

Lack of association between body mass index and plasma adiponectin levels in healthy adults

“…29,45,46,55,57,59 The Pearson's correlation was 0.85 (Po0.05), indicating a significant positive correlation between plasma IL-6 and BMI in healthy adult women. No gender differences were found in plasma levels of TNFa and IL-6.…”

“…29,34,[45][46][47][48][49][50][51][52][53][54][55] Female data were compiled from 15 studies (26 groups of individuals), with study sample size ranging from 8 to 662 individuals and a mean sample size of 94. 29,45,46,48,50,[53][54][55][56][57][58][59][60][61][62] Lack of BMI-adiponectin association S-M Kuo and MM Halpern Among these studies, eight studies included subjects of both genders and the measurements from men and women were reported separately. The sample size as well as the age and BMI profiles of these studies are summarized in Table 1.…”

“…After applying our data exclusion criteria, we found very limited information available on the plasma TNFa level of healthy adult men (Figure 3a), 29,55 so regression analysis was not possible. The regression analysis of female TNFa to BMI was based on data from 12 groups (Figure 3b) 29,55,[57][58][59][60] and Pearson's correlation was 0.51 (P40.05, not significant). There was also limited information available (six groups) on the plasma IL-6 level of healthy adult men (Figure 4a).…”

“…Mean and standard deviation of plasma IL-6 and the corresponding mean BMI were compiled from various male 29,34,45,46 and female 29,45,46,55,57,59 studies included in Table 1. Some error bars are too small to be visible.…”

Transplant-Associated Hyperglycemia

“…Before transplantation, older age, obesity, hepatitis C infection, family history of type 2 diabetes, and metabolic syndrome increase the probability of subsequent glycemic abnormalities through insulin resistance (3). The association of black race with diabetes also seems to be mediated by insulin resistance, although studies of race-specific mechanisms of disease in TAH are lacking (12). After transplantation, corticosteroid use and weight gain may magnify insulin resistance further (13).…”