NIDDM in African-Americans and Black South Africans: Many Similarities but Some Important Differences

Joffe, B. I.; Wing, Jeffrey; Zouvanis, Michael; Pieterse, A.C.; Seftel, H. C.

doi:10.2337/diacare.19.12.1451

Cited by 12 publications

(7 citation statements)

References 10 publications

(15 reference statements)

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“…50,51 The majority of patients demonstrate progressive b-cell failure. This is in keeping with the concept that black Southern Africans either inherit or acquire a decreased pancreatic beta cell mass, 52 and that the functional ability of these b-cells will become rapidly exhausted when glucose intolerance supervenes, with many of the patients requiring insulin therapy to initially restore normoglycemia.…”

Section: Discussionmentioning

confidence: 99%

Evidence for insulin resistance in black women from South Africa

et al. 2000

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OBJECTIVE: The rate of glucose disposal was determined in 10 black and 10 white obese nondiabetic urban women from South Africa to assess insulin resistance. DESIGN AND METHODS: Euglycemic hyperinsulinemic clamp and body composition analysis. RESULTS: Age, body mass index (BMI), anthropometric measurements and body composition were similar in both groups of women. A ®ve-level computed tomography (CT) scan showed a similar mean subcutaneous fat mass in both groups of women (black obese women 555 AE 9.0 vs white obese women 532 AE 6.0 cm 2 ), but less visceral fat in black obese women (90 AE 3.0 vs 121 AE 3.1 cm 2 ; P`0.05). Black obese women had higher fasting free fatty acid (997 AE 69 vs 678 AE 93 m mmolal; P`0.05) and lactate concentrations (1462 AE 94 vs 1038 AE 39 m mmolal; P`0.05), but lower fasting insulin levels (87 AE 12 vs 155 AE 9 pmolal; P`0.001). Black obese women also had a more favorable HDL: total cholesterol ratio (30.5% vs 23.0%; P`0.04). The mean glucose disposal rate (M) and disposal expressed as glucose sensitivity index (MaI) were reduced in the black obese women vs white obese women (M: 7.1 AE 0.8 vs 13.7 AE 1.0 mmolakg Á min À1 Â100; P`0.01, and MaI: 0.12 AE 0.01 vs 0.24 AE 0.02 mmolakg Á min À1 apmolal Â1000; P`0.01). Only black obese women showed a signi®cant decrease in C-peptide levels during the clamp (2.9 AE 0.22 vs 1.2 AE 0.12 nmolal; P`0.001). During the euglycemic period, the black obese women had higher lactate levels at all time points, but only the white obese women had increased lactate levels (918 AE 66 to 1300 AE 53 m mmolal; P`0.05). CONCLUSION: Black obese women demonstrate a higher degree of insulin resistance, despite less visceral fat and a higher HDL: total-cholesterol ratio. In addition, endogenous b b-cell secretory function in black obese women appears to be more sensitive to the suppressive effect of exogenous insulin administration. The signi®cant increase in lactate levels in white obese women con®rms that they are more insulin sensitive.

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Section: Discussionmentioning

confidence: 99%

Evidence for insulin resistance in black women from South Africa

et al. 2000

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“…[6][7][8] Furthermore, among Afro-Caribbeans in the United Kingdom, CHD is also more prevalent in the diabetic population in comparison with those in Africans in South Africa, although lower than in the United Kingdom white diabetic population. 9,10 The lipid profiles in South African diabetic Africans exhibit some similarities to those of the uncommon insulin sensitive phenotype found among diabetic African-Americans, [11][12][13] and both are characterized by relatively low triglyceride (TG) and total cholesterol concentrations. Because insulin resistance itself is an independent risk factor for CHD in type 2 diabetic subjects, 14,15 we have recently postulated that lesser degrees of insulin resistance (IR) in African patients may contribute to their lower risk for CHD 5 ; however, surrogate measures of IR-TG levels and the TG:high-density lipoprotein cholesterol (TG:HDL-C) ratio were used in that analysis.…”

Section: Introductionmentioning

confidence: 96%

The Metabolic Syndrome, Insulin Resistance, and Its Surrogates in African and White Subjects with Type 2 Diabetes in South Africa

Kalk

Joffe

2008

Metabolic Syndrome and Related Disorders

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In diabetic Africans, in comparison with white patients, the lower prevalence of the metabolic syndrome in men and severe metabolic syndrome in women, and lesser insulin resistance, might contribute to their lower risk of CHD; the higher prevalence in women might contribute to the reversal of the male:female ratio. The TG:HDL-C ratio appears to be a valid estimate of insulin resistance in diabetic Africans.

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“…It is also unknown whether the results on African-Americans hold true for South Africans (16,17). The South African Demographic and Health Survey (18) described high rates of obesity, with women showing the highest levels for being obese or overweight (56%).…”

Section: Introductionmentioning

confidence: 99%

Differences and similarities regarding adiponectin investigated in African and Caucasian women

Schutte

Huisman²,

Schutte³

et al. 2007

eur j endocrinol

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Objective: Concentrations of adiponectin, an adipocytokine with insulin-sensitizing actions, may vary according to ethnic group. This study aimed to determine whether fasting adiponectin levels of Caucasian and African women differ. A second objective was to determine which components of the metabolic syndrome are more closely related to adiponectinemia in both groups. Design: A cross-sectional study including 102 urban African and 115 Caucasian women with a wide range of obesity aged 20-55 years. Methods: Anthropometric measurements were taken, namely weight, height, body mass index, waist circumference, and hip circumference. Cardiovascular measurements included blood pressure and arterial compliance. Fasting blood samples were taken to determine glucose, insulin, C-peptide, leptin, adiponectin, and lipid levels. Results: Mean adiponectin levels of the whole groups did not differ, but normal weight African women (NZ38) showed marginally lower adiponectin levels than their Caucasian counterparts (NZ41; PZ0.047). No differences in adiponectin were shown for overweight and obese women. Separate multiple regression analyses for ethnic groups showed that only homeostasis model assessment-insulin resistance (HOMA-IR) significantly contributed to the variance in adiponectin levels of African women, whereas leptin, triacylglycerol levels and HOMA-IR contributed significantly to adiponectin variance in Caucasian women. An additional multiple regression analysis in a combined ethnic group (NZ217) showed ethnicity to be a significant contributor to variances in adiponectin levels. Conclusions: Even though adiponectin levels of these ethnic groups are similar, different associations of adiponectin with leptin and triacylglycerol levels might indicate that there are ethnic differences regarding the mechanistic functions of adiponectin within the scope of the metabolic syndrome.

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NIDDM in African-Americans and Black South Africans: Many Similarities but Some Important Differences

Cited by 12 publications

References 10 publications

Evidence for insulin resistance in black women from South Africa

Evidence for insulin resistance in black women from South Africa

The Metabolic Syndrome, Insulin Resistance, and Its Surrogates in African and White Subjects with Type 2 Diabetes in South Africa

Differences and similarities regarding adiponectin investigated in African and Caucasian women

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