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- Goedecke, Julia H., et al.
(författare)
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Waist circumference thresholds predicting incident dysglycaemia and type 2 diabetes in Black African men and women
- 2022
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Ingår i: Diabetes, obesity and metabolism. - : John Wiley & Sons. - 1462-8902 .- 1463-1326. ; 24:5, s. 918-927
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To determine the waist circumference (WC) thresholds for the prediction of incident dysglycaemia and type 2 diabetes (T2D) in Black South African (SA) men and women and to compare these to the advocated International Diabetes Federation (IDF) Europid thresholds.Materials and Methods: In this prospective study, Black SA men (n = 502) and women (n = 527) from the Middle-aged Sowetan Cohort study who had normal or impaired fasting glucose at baseline (2011-2015) were followed up until 2017 to 2018. Baseline measurements included anthropometry, blood pressure and fasting glucose, HDL cholesterol and triglyceride concentrations. At follow-up, glucose tolerance was assessed using an oral glucose tolerance test. The Youden index was used to determine the optimal threshold of WC to predict incident dysglycaemia and T2D.Results: In men, the optimal WC threshold was 96.8 cm for both dysglycaemia and T2D (sensitivity: 56% and 70%; specificity: 74% and 70%, respectively), and had higher specificity (P < 0.001) than the IDF threshold of 94 cm. In women, the optimal WC threshold for incident dysglycaemia was 91.8 cm (sensitivity 86%, specificity 37%) and for T2D it was 95.8 cm (sensitivity 85%, specificity 45%), which had lower sensitivity, but higher specificity to predict incident dysglycaemia and T2D than the IDF threshold of 80 cm (sensitivity: 97% and 100%; specificity: 12% and 11%, respectively)).Conclusions: We show for the first time using prospective cohort data from Africa that the IDF Europid WC thresholds are not appropriate for an African population, and show that African-specific WC thresholds perform better than the IDF Europid thresholds to predict incident dysglycaemia and T2D.
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| 2. |
- Kufe, Clement N., et al.
(författare)
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Increased risk for type 2 diabetes in relation to adiposity in middle-aged Black South African men compared to women
- 2022
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Ingår i: European Journal of Endocrinology. - : Bioscientifica. - 0804-4643 .- 1479-683X. ; 186:5, s. 523-533
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Despite a higher prevalence of overweight/obesity in Black South African women compared to men, the prevalence of type 2 diabetes (T2D) does not differ. We explored if this could be due to sex differences in insulin sensitivity, clearance and/or beta-cell function and also sex-specific associations with total and regional adiposity.Methods: This cross-sectional study included 804 Black South African men (n = 388) and women (n = 416). Dual-energy X-ray absorptiometry was used to measure total and regional adiposity. Insulin sensitivity (Matsuda index), secretion (C-peptide index) and clearance (C-peptide/insulin ratio) were estimated from an oral glucose tolerance test.Results: After adjusting for sex differences in the fat mass index, men were less insulin sensitive and had lower beta-cell function than women (P < 0.001), with the strength of the associations with measures of total and central adiposity being greater in men than women (P < 0.001 for interactions). Further, the association between total adiposity and T2D risk was also greater in men than women (relative risk ratio (95% CI): 2.05 (1.42-2.96), P < 0.001 vs 1.38 (1.03-1.85), P = 0.031).Conclusion: With increasing adiposity, particularly increased centralisation of body fat linked to decreased insulin sensitivity and beta-cell function, Black African men are at greater risk for T2D than their female counterparts.
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| 3. |
- Kufe, Nyuyki Clement, et al.
(författare)
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Protocol for systematic review and meta-analysis of sex hormones and diabetes risk in ageing men and women of African ancestry
- 2019
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 9:1
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Forskningsöversikt (refereegranskat)abstract
- Aim: To present the protocol of a systematic review and meta-analysis of the available evidence examining the association between sex hormones and type 2 diabetes risk in ageing men and women of African descent.Methods: We shall conduct a comprehensive search of published studies that examined the association between sex hormones and type 2 diabetes risk in men and women aged ≥40 years from 01/01/1980 to 31/03/2018 with no language restriction. Databases to be searched include: PubMed, Scopus, Cochrane Library, Cumulative Index to Nursing and Allied Health, ISI Web of Science, Clinical Trial registries, Google Scholar and institutional websites such as the WHO, American Diabetes Association, International Diabetes Federation, World Diabetes Foundation, European Association for the Study of Diabetes, African Journal Online and ProQuest databases. This protocol is developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. Independent screening for eligible studies using defined criteria and data extraction, will be completed in duplicate. Discrepancies will be resolved by consensus or consultation with a third researcher. Risk of bias of included studies will be assessed by the appropriate Cochrane risk of bias tool. The overall association estimates will be pooled using appropriate meta-analytic techniques. Heterogeneity will be assessed using Cochrane Q statistic and the inconsistency index (I2). The random effects model will be used to calculate a pooled estimate.Ethics and dissemination: No ethics clearance is required as no primary data will be collected. The systematic review and meta-analysis are part of a PhD project at WITS University (Johannesburg, South Africa) and results will be presented at conferences and published in a peer-review journal. The results will guide future population specific interventions.
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| 4. |
- Mendham, Amy E., et al.
(författare)
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Targeted proteomics identifies potential biomarkers of dysglycaemia, beta cell function and insulin sensitivity in Black African men and women
- 2023
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Ingår i: Diabetologia. - : Springer. - 0012-186X .- 1432-0428. ; 66, s. 174-189
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis: Using a targeted proteomics approach, we aimed to identify and validate circulating proteins associated with impaired glucose metabolism (IGM) and type 2 diabetes in a Black South African cohort. In addition, we assessed sex-specific associations between the validated proteins and pathophysiological pathways of type 2 diabetes.Methods: This cross-sectional study included Black South African men (n=380) and women (n=375) who were part of the Middle-Aged Soweto Cohort (MASC). Dual-energy x-ray absorptiometry was used to determine fat mass and visceral adipose tissue, and fasting venous blood samples were collected for analysis of glucose, insulin and C-peptide and for targeted proteomics, measuring a total of 184 pre-selected protein biomarkers. An OGTT was performed on participants without diabetes, and peripheral insulin sensitivity (Matsuda index), HOMA-IR, basal insulin clearance, insulin secretion (C-peptide index) and beta cell function (disposition index) were estimated. Participants were classified as having normal glucose tolerance (NGT; n=546), IGM (n=116) or type 2 diabetes (n=93). Proteins associated with dysglycaemia (IGM or type 2 diabetes) in the MASC were validated in the Swedish EpiHealth cohort (NGT, n=1706; impaired fasting glucose, n=550; type 2 diabetes, n=210).Results: We identified 73 proteins associated with dysglycaemia in the MASC, of which 34 were validated in the EpiHealth cohort. Among these validated proteins, 11 were associated with various measures of insulin dynamics, with the largest number of proteins being associated with HOMA-IR. In sex-specific analyses, IGF-binding protein 2 (IGFBP2) was associated with lower HOMA-IR in women (coefficient –0.35; 95% CI –0.44, –0.25) and men (coefficient –0.09; 95% CI –0.15, –0.03). Metalloproteinase inhibitor 4 (TIMP4) was associated with higher insulin secretion (coefficient 0.05; 95% CI 0.001, 0.11; p for interaction=0.025) and beta cell function (coefficient 0.06; 95% CI 0.02, 0.09; p for interaction=0.013) in women only. In contrast, a stronger positive association between IGFBP2 and insulin sensitivity determined using an OGTT (coefficient 0.38; 95% CI 0.27, 0.49) was observed in men (p for interaction=0.004). A posteriori analysis showed that the associations between TIMP4 and insulin dynamics were not mediated by adiposity. In contrast, most of the associations between IGFBP2 and insulin dynamics, except for insulin secretion, were mediated by either fat mass index or visceral adipose tissue in men and women. Fat mass index was the strongest mediator between IGFBP2 and insulin sensitivity (total effect mediated 40.7%; 95% CI 37.0, 43.6) and IGFBP2 and HOMA-IR (total effect mediated 39.1%; 95% CI 31.1, 43.5) in men.Conclusions/interpretation: We validated 34 proteins that were associated with type 2 diabetes, of which 11 were associated with measures of type 2 diabetes pathophysiology such as peripheral insulin sensitivity and beta cell function. This study highlights biomarkers that are similar between cohorts of different ancestry, with different lifestyles and sociodemographic profiles. The African-specific biomarkers identified require validation in African cohorts to identify risk markers and increase our understanding of the pathophysiology of type 2 diabetes in African populations.
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