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Cardiometabolic disease in Black African and Caribbean populations: an ethnic divergence in pathophysiology?
Reed, RM, Whyte, MB, Goff, LM
The Proceedings of the Nutrition Society. 2023;:1-11
Abstract
In the UK, populations of Black African and Caribbean (BAC) ethnicity suffer higher rates of cardiometabolic disease than White Europeans (WE). Obesity, leading to increased visceral adipose tissue (VAT) and intrahepatic lipid (IHL), has long been associated with cardiometabolic risk, driving insulin resistance and defective fatty acid/lipoprotein metabolism. These defects are compounded by a state of chronic low-grade inflammation, driven by dysfunctional adipose tissue. Emerging evidence has highlighted associations between central complement system components and adipose tissue, fatty acid metabolism and inflammation; it may therefore sit at the intersection of various cardiometabolic disease risk factors. However, increasing evidence suggests an ethnic divergence in pathophysiology, whereby current theories fail to explain the high rates of cardiometabolic disease in BAC populations. Lower fasting and postprandial TAG has been reported in BAC, alongside lower VAT and IHL deposition, which are paradoxical to the high rates of cardiometabolic disease exhibited by this ethnic group. Furthermore, BAC have been shown to exhibit a more anti-inflammatory profile, with lower TNF-α and greater IL-10. In contrast, recent evidence has revealed greater complement activation in BAC compared to WE, suggesting its dysregulation may play a greater role in the high rates of cardiometabolic disease experienced by this population. This review outlines the current theories of how obesity is proposed to drive cardiometabolic disease, before discussing evidence for ethnic differences in disease pathophysiology between BAC and WE populations.
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Ectopic fat deposition in populations of black African ancestry: A systematic review and meta-analysis.
Reed, RM, Nevitt, SJ, Kemp, GJ, Cuthbertson, DJ, Whyte, MB, Goff, LM
Acta diabetologica. 2022;(2):171-187
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Abstract
AIMS: In populations of black African ancestry (BA), a paradox exists whereby lower visceral adipose tissue is found despite their high risk for type 2 diabetes (T2D). This systematic review investigates ethnic differences in other ectopic fat depots (intrahepatic lipid: IHL; intramyocellular lipid: IMCL and intrapancreatic lipid; IPL) to help contextualise their potential contribution to T2D risk. METHODS A systematic literature search was performed in December 2020 to identify studies reporting at least one ectopic fat comparison between BA and one/more other ethnicity. For IHL, a meta-analysis was carried out with studies considered comparable based on the method of measurement. RESULTS Twenty-eight studies were included (IHL: n = 20; IMCL n = 8; IPL: n = 4). Meta-analysis of 11 studies investigating IHL revealed that it was lower in BA populations vs pooled ethnic comparators (MD -1.35%, 95% CI -1.55 to -1.16, I2 = 85%, P < 0.00001), white European ancestry (MD -0.94%, 95% CI -1.17 to -0.70, I2 = 79%, P < 0.00001), Hispanic ancestry (MD -2.06%, 95% CI -2.49 to -1.63, I2 = 81%, P < 0.00001) and South Asian ancestry comparators (MD -1.92%, 95% CI -3.26 to -0.57, I2 = 78%, P = 0.005). However, heterogeneity was high in all analyses. Most studies found no significant differences in IMCL between BA and WE. Few studies investigated IPL, however, indicated that IPL is lower in BA compared to WE and HIS. CONCLUSION The discordance between ectopic fat and greater risk for T2D in BA populations raises questions around its contribution to T2D pathophysiology in BA.
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Culturally tailored lifestyle interventions for the prevention and management of type 2 diabetes in adults of Black African ancestry: a systematic review of tailoring methods and their effectiveness.
Wadi, NM, Asantewa-Ampaduh, S, Rivas, C, Goff, LM
Public health nutrition. 2022;(2):422-436
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Abstract
OBJECTIVE To evaluate the cultural tailoring methods used in type 2 diabetes (T2D), prevention and management interventions for populations of Black African ancestry and to examine their effectiveness on measures of glycaemia. DESIGN Three databases were searched in October 2020; eligible studies used a randomised controlled trial (RCT) design to evaluate the effectiveness of culturally tailored lifestyle interventions compared with usual care for the prevention or management of T2D in adults of Black African ancestry. Cultural tailoring methods were evaluated using the Facilitator-Location-Language-Messaging (FiLLM) framework, whereby facilitator refers to delivery by individuals from the target community, language focuses on using native language or language appropriate to literacy levels, location refers to delivery in meaningful settings, and messaging is tailoring with relevant content and modes of delivery. RESULTS Sixteen RCT were identified, all from USA. The mean age of participants was 55 years, majority female. Six of fifteen RCT reported significant improvements in glycated haemoglobin (HbA1c) at 6 and 8 months; one, in prediabetes, reported significantly improved fasting plasma glucose. Diabetes knowledge improvement (5/7 studies) was associated with HbA1c improvement. The majority tailored to location (12/16), facilitators (11/16), messaging (9/16) and language (6/16) domains of FiLLM. Those with ethnically matched facilitators and those which tailored to more than one domain showed the greatest HbA1C benefits. CONCLUSION This evidence supports the effectiveness of culturally tailored lifestyle interventions for T2D management in populations of Black African ancestry, with further RCT needed to evaluate interventions for T2D prevention and for communities outside of the USA.
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Ethnic differences in beta cell function occur independently of insulin sensitivity and pancreatic fat in black and white men.
Ladwa, M, Bello, O, Hakim, O, Shojaee-Moradie, F, Boselli, ML, Charles-Edwards, G, Peacock, J, Umpleby, AM, Amiel, SA, Bonadonna, RC, et al
BMJ open diabetes research & care. 2021;(1)
Abstract
INTRODUCTION It is increasingly recognized that type 2 diabetes (T2D) is a heterogenous disease with ethnic variations. Differences in insulin secretion, insulin resistance and ectopic fat are thought to contribute to these variations. Therefore, we aimed to compare postprandial insulin secretion and the relationships between insulin secretion, insulin sensitivity and pancreatic fat in men of black West African (BA) and white European (WE) ancestry. RESEARCH DESIGN AND METHODS A cross-sectional, observational study in which 23 WE and 23 BA men with normal glucose tolerance, matched for body mass index, underwent a mixed meal tolerance test with C peptide modeling to measure beta cell insulin secretion, an MRI to quantify intrapancreatic lipid (IPL), and a hyperinsulinemic-euglycemic clamp to measure whole-body insulin sensitivity. RESULTS Postprandial insulin secretion was lower in BA versus WE men following adjustment for insulin sensitivity (estimated marginal means, BA vs WE: 40.5 (95% CI 31.8 to 49.2) × 103 vs 56.4 (95% CI 48.9 to 63.8) × 103 pmol/m2 body surface area × 180 min, p=0.008). There was a significantly different relationship by ethnicity between IPL and insulin secretion, with a stronger relationship in WE than in BA (r=0.59 vs r=0.39, interaction p=0.036); however, IPL was not a predictor of insulin secretion in either ethnic group following adjustment for insulin sensitivity. CONCLUSIONS Ethnicity is an independent determinant of beta cell function in black and white men. In response to a meal, healthy BA men exhibit lower insulin secretion compared with their WE counterparts for their given insulin sensitivity. Ethnic differences in beta cell function may contribute to the greater risk of T2D in populations of African ancestry.
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Healthy Eating and Active Lifestyles for Diabetes (HEAL-D), a culturally tailored self-management education and support program for type 2 diabetes in black-British adults: a randomized controlled feasibility trial.
Goff, LM, Rivas, C, Moore, A, Beckley-Hoelscher, N, Reid, F, Harding, S
BMJ open diabetes research & care. 2021;(1)
Abstract
INTRODUCTION Black-British communities are disproportionately affected by type 2 diabetes (T2D). Structured education programs are a core component of T2D healthcare but they are less successful in people from minority ethnic groups. Culturally tailored T2D education has demonstrated greater benefits than usual care. The aim of our study was to evaluate acceptability, fidelity and trial feasibility of the Healthy Eating and Active Lifestyles for Diabetes ('HEAL-D') culturally tailored T2D self-management education and support (DSMES) program. RESEARCH DESIGN AND METHODS A mixed-methods randomized controlled feasibility trial in black-British adults with T2D was conducted. Participants were assigned to control (usual care) or intervention (HEAL-D; 7 sessions, 14 hours of group-based culturally tailored diet and lifestyle education, behavior change support and supervised physical activity), in a ratio of 1:1. Primary outcomes were recruitment and retention rates, intervention attendance and completion. Fidelity was assessed through observations and qualitative evaluation was undertaken with participants and educators. RESULTS 102 patients responded to invitation letters (n=1335); 63 were randomized but 8 were subsequently deemed ineligible due to high baseline glycosylated hemoglogin (HbA1c) requiring intensive medical management or missing baseline HbA1c measurement. Of the remaining 55 participants (27 intervention, 28 control), 69% were female, 47% were of African and 51% were of Caribbean ethnicity. 93% completed the trial, providing end point data. Intervention attendance was high; 85% completed the program (attendance at ≥5 sessions), and 74% attended ≥6 sessions. The intervention was delivered with acceptable fidelity, although the qualitative evaluations identified some areas of structure and format in need of refinement. CONCLUSIONS We have shown it is feasible to recruit and randomize black-British adults with T2D to a trial of a culturally tailored DSMES program. We have shown the intervention is highly acceptable for both patients and healthcare providers. A future trial should assess clinical and cost-effectiveness of HEAL-D. TRIAL REGISTRATION NUMBER NCT03531177.
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Factors Influencing Pregnancy and Postpartum Weight Management in Women of African and Caribbean Ancestry Living in High Income Countries: Systematic Review and Evidence Synthesis Using a Behavioral Change Theoretical Model.
Moore, AP, Flynn, AC, Adegboye, ARA, Goff, LM, Rivas, CA
Frontiers in public health. 2021;:637800
Abstract
Background: Women of black African heritage living in high income countries (HIC) are at risk of obesity and weight-related complications in pregnancy. This review aimed to synthesize evidence concerning attitudes to weight management-related health behaviors in pregnancy and postpartum, in women of black African ancestry, living in high-income countries. Methods: A systematic review of the literature and thematic evidence synthesis using the Capability-Opportunity-Motivation Behavioral change theoretical model (COM-B). Databases searched included MEDLINE, EMBASE, Web of Science, and Scopus. The CASP tool was used to assess quality. Results: Twenty-four papers met the selection criteria, most of which were from the US. Motivational factors were most commonly described as influencers on behavior. Normative beliefs about "eating for two," weight gain being good for the baby, the baby itself driving food choice, as well as safety concerns about exercising in pregnancy, were evident and were perpetuated by significant others. These and other social norms, including a cultural acceptance of larger body shapes, and daily fast food, created a challenge for healthy behavior change. Women also had low confidence in their ability to lose weight in the postpartum period. Behavior change techniques, such as provision of social support, use of credible sources, and demonstration may be useful to support change. Conclusions: The women face a range of barriers to engagement in weight-related health behaviors at this life-stage. Using a theoretical behavior change framework can help identify contextual factors that may limit or support behavior change.
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Effect of exercise training on insulin sensitivity, hyperinsulinemia and ectopic fat in black South African women: a randomized controlled trial.
Fortuin-de Smidt, MC, Mendham, AE, Hauksson, J, Hakim, O, Stefanovski, D, Clamp, L, Phiri, L, Swart, J, Goff, LM, Micklesfield, LK, et al
European journal of endocrinology. 2020;(1):51-61
Abstract
OBJECTIVE We investigated the effects of a 12-week exercise intervention on insulin sensitivity (SI) and hyperinsulinemia and associated changes in regional and ectopic fat. RESEARCH DESIGN AND METHODS Healthy, black South African women with obesity (mean age 23 ± 3.5 years) and of isiXhosa ancestry were randomised into a 12-week aerobic and resistance exercise training group (n = 23) and a no exercise group (control, n = 22). Pre and post-intervention testing included assessment of SI, insulin response to glucose (AIRg), insulin secretion rate (ISR), hepatic insulin extraction (FEL) and disposition index (DI) (AIRg × SI) (frequently sampled i.v. glucose tolerance test); fat mass and regional adiposity (dual-energy X-ray absorptiometry); hepatic, pancreatic and skeletal muscle fat content and abdominal s.c. and visceral adipose tissue volumes (MRI). RESULTS Exercise training increased VO2peak (mean ± s.d.: 24.9 ± 2.42 to 27.6 ± 3.39 mL/kg/min, P < 0.001), SI (2.0 (1.2-2.8) to 2.2 (1.5-3.7) (mU/l)-1 min-1, P = 0.005) and DI (median (interquartile range): 6.1 (3.6-7.1) to 6.5 (5.6-9.2) × 103 arbitrary units, P = 0.028), and decreased gynoid fat mass (18.5 ± 1.7 to 18.2 ± 1.6%, P < 0.001) and body weight (84.1 ± 8.7 to 83.3 ± .9.7 kg, P = 0.038). None of these changes were observed in the control group, but body weight increased (P = 0.030). AIRg, ISR and FEL, VAT, SAT and ectopic fat were unaltered after exercise training. The increase in SI and DI were not associated with changes in regional or ectopic fat. CONCLUSION Exercise training increased SI independent from changes in hyperinsulinemia and ectopic fat, suggesting that ectopic fat might not be a principal determinant of insulin resistance in this cohort.
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Exercise training results in depot-specific adaptations to adipose tissue mitochondrial function.
Mendham, AE, Larsen, S, George, C, Adams, K, Hauksson, J, Olsson, T, Fortuin-de Smidt, MC, Nono Nankam, PA, Hakim, O, Goff, LM, et al
Scientific reports. 2020;(1):3785
Abstract
We assessed differences in mitochondrial function in gluteal (gSAT) and abdominal subcutaneous adipose tissue (aSAT) at baseline and in response to 12-weeks of exercise training; and examined depot-specific associations with body fat distribution and insulin sensitivity (SI). Obese, black South African women (n = 45) were randomized into exercise (n = 23) or control (n = 22) groups. Exercise group completed 12-weeks of aerobic and resistance training (n = 20), while the control group (n = 15) continued usual behaviours. Mitochondrial function (high-resolution respirometry and fluorometry) in gSAT and aSAT, SI (frequently sampled intravenous glucose tolerance test), body composition (dual-energy X-ray absorptiometry), and ectopic fat (MRI) were assessed pre- and post-intervention. At baseline, gSAT had higher mitochondrial respiratory capacity and hydrogen peroxide (H2O2) production than aSAT (p < 0.05). Higher gSAT respiration was associated with higher gynoid fat (p < 0.05). Higher gSAT H2O2 production and lower aSAT mitochondrial respiration were independently associated with lower SI (p < 0.05). In response to training, SI improved and gynoid fat decreased (p < 0.05), while H2O2 production reduced in both depots, and mtDNA decreased in gSAT (p < 0.05). Mitochondrial respiration increased in aSAT and correlated with a decrease in body fat and an increase in soleus and hepatic fat content (p < 0.05). This study highlights the importance of understanding the differences in mitochondrial function in multiple SAT depots when investigating the pathophysiology of insulin resistance and associated risk factors such as body fat distribution and ectopic lipid deposition. Furthermore, we highlight the benefits of exercise training in stimulating positive adaptations in mitochondrial function in gluteal and abdominal SAT depots.
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Ethnic distinctions in the pathophysiology of type 2 diabetes: a focus on black African-Caribbean populations.
Goff, LM, Ladwa, M, Hakim, O, Bello, O
The Proceedings of the Nutrition Society. 2020;(2):184-193
Abstract
Type 2 diabetes (T2D) is a global public health priority, particularly for populations of black African-Caribbean ethnicity, who suffer disproportionately high rates of the disease. While the mechanisms underlying the development of T2D are well documented, there is growing evidence describing distinctions among black African-Caribbean populations. In the present paper, we review the evidence describing the impact of black African-Caribbean ethnicity on T2D pathophysiology. Ethnic differences were first recognised through evidence that metabolic syndrome diagnostic criteria fail to detect T2D risk in black populations due to less central obesity and dyslipidaemia. Subsequently more detailed investigations have recognised other mechanistic differences, particularly lower visceral and hepatic fat accumulation and a distinctly hyperinsulinaemic response to glucose stimulation. While epidemiological studies have reported exaggerated insulin resistance in black populations, more detailed and direct measures of insulin sensitivity have provided evidence that insulin sensitivity is not markedly different to other ethnic groups and does not explain the hyperinsulinaemia that is exhibited. These findings lead us to hypothesise that ectopic fat does not play a pivotal role in driving insulin resistance in black populations. Furthermore, we hypothesise that hyperinsulinaemia is driven by lower rates of hepatic insulin clearance rather than heightened insulin resistance and is a primary defect rather than occurring in compensation for insulin resistance. These hypotheses are being investigated in our ongoing South London Diabetes and Ethnicity Phenotyping study, which will enable a more detailed understanding of ethnic distinctions in the pathophysiology of T2D between men of black African and white European ethnicity.
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Associations of dietary intake with cardiometabolic risk in a multi-ethnic cohort: a longitudinal analysis of the Determinants of Adolescence, now young Adults, Social well-being and Health (DASH) study.
Goff, LM, Huang, P, Silva, MJ, Bordoli, C, Enayat, EZ, Molaodi, OR, Cassidy, A, Maynard, M, Harding, S
The British journal of nutrition. 2019;121(9):1069-1079
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Plain language summary
Ethnic inequalities in a wide range of chronic diseases are well documented. Poor dietary habits in childhood may contribute to higher rates of chronic diseases such as type 2 diabetes (T2D), hypertension and Coronary Heart Disease (CHD). This study was a longitudinal follow-up of a subsample of the Determinants of Adolescent Social well-being and Health (DASH) study. The researchers aimed to identify dietary patterns and investigate their impact on chronic diseases in young adulthood. The study participants were 107 White British, 102 Black Caribbean, 132 Black African, 98 Indian, 111 Bangladeshi/Pakistani and 115 other/mixed ethnicity. Participants completed a 24-hour dietary intake recall and behaviour questionnaire at age 11-13yrs, and then again at age 21-23yrs. Body mass index (BMI), blood pressure, blood cholesterol and blood sugar were measured. The researchers found that dietary behaviours such as skipping breakfast and a low intake of fruit and vegetables were common. Rates of skipping breakfast and low fruit and vegetable consumption were highest among Black African and Black Caribbean participants. BMI and cholesterol levels in young adults were higher among those who regularly skipped breakfast. The researchers concluded that skipping breakfast is more common in certain ethnic groups and is associated with risk factors for chronic disease in young adults. They suggest that interventions to improve dietary habits could be targeted at specific population groups.
Abstract
Unfavourable dietary habits, such as skipping breakfast, are common among ethnic minority children and may contribute to inequalities in cardiometabolic disease. We conducted a longitudinal follow-up of a subsample of the UK multi-ethnic Determinants of Adolescent Social well-being and Health cohort, which represents the main UK ethnic groups and is now aged 21-23 years. We aimed to describe longitudinal patterns of dietary intake and investigate their impact on cardiometabolic risk in young adulthood. Participants completed a dietary behaviour questionnaire and a 24 h dietary intake recall; anthropometry, blood pressure, total cholesterol and HDL-cholesterol and HbA1c were measured. The cohort consisted of 107 White British, 102 Black Caribbean, 132 Black African, 98 Indian, 111 Bangladeshi/Pakistani and 115 other/mixed ethnicity. Unhealthful dietary behaviours such as skipping breakfast and low intake of fruits and vegetables were common (56, 57 and 63 %, respectively). Rates of skipping breakfast and low fruit and vegetable consumption were highest among Black African and Black Caribbean participants. BMI and cholesterol levels at 21-23 years were higher among those who regularly skipped breakfast at 11-13 years (BMI 1·41 (95 % CI 0·57, 2·26), P=0·001; cholesterol 0·15 (95 % CI -0·01, 0·31), P=0·063) and at 21-23 years (BMI 1·05 (95 % CI 0·22, 1·89), P=0·014; cholesterol 0·22 (95 % CI 0·06, 0·37), P=0·007). Childhood breakfast skipping is more common in certain ethnic groups and is associated with cardiometabolic risk factors in young adulthood. Our findings highlight the importance of targeting interventions to improve dietary behaviours such as breakfast consumption at specific population groups.