Visceral adipose tissue is not increased in Pima Indians compared with equally obese Caucasians and is not related to insulin action or secretion

Gautier, J.F.; Milner, M.R.; El-Am, Edward; Chen, Kewei; Ravussin, Éric; Pratley, Richard E.

doi:10.1007/s001250051108

Cited by 46 publications

(31 citation statements)

References 31 publications

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“…For instance, the Pima Indians of Arizona (a population with the highest reported prevalence of type 2 diabetes in the world) have, like Hispanics, a central pattern of fat distribution (33). However, in this ethnic group, directly measured visceral fat (assessed by MRI) was not related to glucose disposal rate during a hyperinsulinemiceuglycemic clamp (34). Furthermore, the visceral fat accumulation did not explain the differences in insulin action and secretion between Pima Indians and Caucasians (33).…”

Section: Resultsmentioning

confidence: 86%

Unique Effect of Visceral Fat on Insulin Sensitivity in Obese Hispanic Children With a Family History of Type 2 Diabetes

2002

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OBJECTIVE -This study aimed to establish whether total fat or central fat was related to measures of insulin in obese Hispanic children with a family history of type 2 diabetes.RESEARCH DESIGN AND METHODS -Subjects were 32 children aged 8 -13 years. Visceral fat and subcutaneous abdominal fat were determined by magnetic resonance imaging at the umbilicus and total body fat was determined by dual-energy X-ray absorptiometry. Insulin sensitivity (S i ) and acute insulin response (AIR) were determined by frequently sampled intravenous tolerance test with minimal modeling.RESULTS -Mean fasting glucose and insulin, S i , and AIR (Ϯ SD) were 5.3 Ϯ 0.3 mmol/l, 206 Ϯ 105 pmol/l, 11.8 Ϯ 5.7 [ϫ 10 Ϫ4 min -1 /(pmol/l)], and 17,175 Ϯ 9,695 (pmol/l ϫ 10 min), respectively. In multivariate regression analysis, total fat mass was independently and positively related to fasting insulin (P Ͻ 0.01) and negatively related to S i (P Ͻ 0.05) but was not related to AIR. Visceral fat was independently and positively related to fasting insulin (P Ͻ 0.05) and AIR (P Ͻ 0.01) and negatively related to S i (P Ͻ 0.001).CONCLUSIONS -These findings support the hypothesis that specific accumulation of visceral fat in addition to overall adiposity in Hispanic children increases the risk of type 2 diabetes. Diabetes Care 25:1631-1636, 2002T he association between obesity and insulin resistance has been well documented, and it has been hypothesized that specific metabolic effects of visceral fat may explain this association (1). Support for a causal role of visceral fat causing insulin resistance has been shown in animal studies in which surgical removal of visceral fat in obese rats reversed insulin resistance (2) and in animal studies in aging rats in which the loss in visceral fat, as a consequence of caloric restriction, resulted in improvement in hepatic insulin sensitivity (S i ) (3).Visceral fat seems to be metabolically unique compared with subcutaneous abdominal fat. Bjorntorp (4) suggested that visceral fat results in hepatic insulin resistance via a "portal" effect of free fatty acids released by increased omental fat. The increased flux of fatty acids to the liver leads to increased hepatic glucose production (5, 6) and decreased hepatic insulin clearance, which in turn leads to insulin resistance and hyperinsulinemia. In children as in adults, central fat seems to be related to S i . However, the precise depot that is associated with S i is not entirely clear and may differ with obesity status (7-9).Although the relationship between central fat and S i has been widely studied in Caucasians, there are very few reports in the Hispanic population. Studies in Hispanic Americans may be important because both children and adults in this subgroup of the population are more obese (10,11), have higher waist-to-hip ratios (12,13), and have higher insulin levels (11) than Caucasians (13). In addition, Hispanic adults have been found to be more insulin-resistant than Caucasians (13) and have greater central distribution of fat (14) at similar le...

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Section: Resultsmentioning

confidence: 86%

Unique Effect of Visceral Fat on Insulin Sensitivity in Obese Hispanic Children With a Family History of Type 2 Diabetes

2002

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“…Among white subjects, the AIR correlates with indices of body fat distribution [73]. In contrast, among Pima Indians the AIR is not related (p = 0.66) to the waist-to-thigh ratio (an index of body fat distribution) after adjusting for age, sex, percent of body fat and insulin action in multiple regression analyses, nor is it related to the amount of visceral fat [74].…”

Section: Determinants Of First-phase Insulin Secretionmentioning

confidence: 82%

The role of impaired early insulin secretion in the pathogenesis of Type II diabetes mellitus

2001

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Normal glucose tolerance is maintained by a precise balance between insulin secretion from pancreatic beta cells and insulin action on sensitive tissues, principally muscle, adipose tissue and liver [1,2]. Patients with Type II (non-insulin-dependent) diabetes mellitus manifest impairments in insulin secretion and insulin action and an increased rate of endogenous glucose production [1±3]. The relative importance of these abnormalities in the pathogenesis of the disease has been debated for many years. It is now generally accepted that abnormalities in insulin secretion and insulin action contribute to the development of Type II diabetes, whereas the increase in endogenous glucose production is a later phenomenon. Insulin secretory dysfunction in Type II diabetes is both quantitative and qualitative [3±4]. In addition to a relative impairment in the amount of insulin released, the pattern of insulin secretion is abnormal. In this review, we focus on the critical role of impaired early insulin secretion in the pathogenesis of Type II diabetes.Current understanding of the pathophysiology of Type II diabetes is based on the contributions of many laboratories working with different populations around the world. Since 1982, the National Institutes of Health has conducted a longitudinal study of the metabolic predictors of Type II diabetes in the Pima Indians of Arizona [5], a population uniquely suited for such studies because of their extraordinarily high Diabetologia (2001) AbstractPatients with Type II (non-insulin-dependent) diabetes mellitus manifest abnormalities in insulin action and insulin secretion. It is widely accepted that insulin resistance is an early finding, evident before the onset of hyperglycaemia and predictive of the subsequent development of diabetes. Whether abnormalities in insulin secretion also precede and predict diabetes has been debated. However, recent studies clearly indicate that early insulin secretion plays a critical role in maintaining normal glucose homeostasis. Crosssectional analyses show that acute insulin secretory responses (AIR) to intravenous glucose are lower in subjects with impaired glucose tolerance and those at high risk for developing diabetes. Prospectively, a low AIR predicts the development of diabetes in several populations. In longitudinal studies, AIR declines dramatically as patients progress from normal to impaired glucose tolerance and ultimately to diabetes. Early insulin secretion is important for the rapid and efficient suppression of endogenous glucose production after a meal. Thus, loss of early insulin secretion initially leads to post-prandial hyperglycaemia which, as the disease progresses, worsens to clinical hyperglycaemia. Strategies that enhance early insulin secretion improve glucose tolerance and represent a novel and more physiologic approach to improving glycaemic control in patients with Type II diabetes mellitus. [Diabetologia (2001) 44: 929±945]

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“…These data are nonetheless consistent with a similar study in USA Aboriginals showing no difference in VAT between Pima Indians and Caucasians matched for BMI. 84 (ii) Other studies have suggested that abdominal (SAT) depots, which are thicker in adult Asian Indians compared with European Caucasians, are a more important predictor of the metabolic syndrome in Asian Indians than VAT. 85,86 In a recent comprehensive investigation comparing South Asians and Europeans, Kohli et al 87 showed that body fat distribution, as measured by SSAT and DSAT, also differs according to ethnicity and gender.…”

Section: Adipose Tissue Expandabilitymentioning

confidence: 99%

Body composition phenotypes in pathways to obesity and the metabolic syndrome

et al. 2010

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Dynamic changes in body weight have long been recognized as important indicators of risk for debilitating diseases. While weight loss or impaired growth can lead to muscle wastage, as well as to susceptibility to infections and organ dysfunctions, the development of excess fat predisposes to type 2 diabetes and cardiovascular diseases, with insulin resistance as a central feature of the disease entities of the metabolic syndrome. Although widely used as the phenotypic expression of adiposity in population and gene-search studies, body mass index (BMI), that is, weight/height 2 (H 2 ), which was developed as an operational definition for classifying both obesity and malnutrition, has considerable limitations in delineating fat mass (FM) from fat-free mass (FFM), in particular at the individual level. After an examination of these limitations within the constraints of the BMI-FM% relationship, this paper reviews recent advances in concepts about health risks related to body composition phenotypes, which center upon (i) the partitioning of BMI into an FM index (FM/H 2 ) and an FFM index (FFM/H 2 ), (ii) the partitioning of FFM into organ mass and skeletal muscle mass, (iii) the anatomical partitioning of FM into hazardous fat and protective fat and (iv) the interplay between adipose tissue expandability and ectopic fat deposition within or around organs/tissues that constitute the lean body mass. These concepts about body composition phenotypes and health risks are reviewed in the light of race/ethnic variability in metabolic susceptibility to obesity and the metabolic syndrome.

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Visceral adipose tissue is not increased in Pima Indians compared with equally obese Caucasians and is not related to insulin action or secretion

Cited by 46 publications

References 31 publications

Unique Effect of Visceral Fat on Insulin Sensitivity in Obese Hispanic Children With a Family History of Type 2 Diabetes

Unique Effect of Visceral Fat on Insulin Sensitivity in Obese Hispanic Children With a Family History of Type 2 Diabetes

The role of impaired early insulin secretion in the pathogenesis of Type II diabetes mellitus

Body composition phenotypes in pathways to obesity and the metabolic syndrome

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