Relationship of glucose intolerance to coronary risk in Afro-Caribbeans compared with Europeans

Ancestry, ethnicity, and race: explaining inequalities in cardiometabolic disease

Population differences in cardiometabolic disease remain unexplained. Misleading assumptions over genetic explanations are partly due to terminology used to distinguish populations, specifically ancestry, race, and ethnicity. These terms differentially implicate environmental and biological causal pathways, which should inform their use. Genetic variation alone accounts for a limited fraction of population differences in cardiometabolic disease. Research effort should focus on societally driven, lifelong environmental determinants of population differences in disease. Rather than pursuing population stratifiers to personalize medicine, we advocate removing socioeconomic barriers to receipt of and adherence to healthcare interventions, which will have markedly greater impact on improving cardiometabolic outcomes. This requires multidisciplinary collaboration and public and policymaker engagement to address inequalities driven by society rather than biology per se.

Racial and Ethnic Disparities in Peripheral Artery Disease

Peripheral artery disease is an obstructive, atherosclerotic disease of the lower extremities causing significant morbidity and mortality. Black Americans are disproportionately affected by this disease while they are also less likely to be diagnosed and promptly treated. The consequences of this disparity can be grim as Black Americans bear the burden of lower extremity amputation resulting from severe peripheral artery disease. The risk factors of peripheral artery disease and how they differentially affect certain groups are discussed in addition to a review of pharmacological and nonpharmacological treatment modalities. The purpose of this review is to highlight health care inequities and provide a review and resource of available recommendations for clinical management of all patients with peripheral artery disease.

Diabetes and COVID-19: Diseases of racial, social and glucose intolerance

Diabetes and coronavirus disease 2019 (COVID-19) are worldwide pandemics that have had a major impact on public health throughout the globe. Risk factors for developing diabetes and having adverse outcomes of COVID-19 appear to be similar; metabolic factors (such as obesity), non-White ethnicity and poorer socioeconomic status appear to be risk factors for both. Diabetes and COVID-19 have a significant effect on populations adversely affected by health inequality. Whilst we hope that COVID-19 will be mitigated by widespread use of vaccines, no such prospect exists for mitigating the pandemic of diabetes. In this brief opinion review, I compare risk factors for diabetes and adverse outcomes of COVID-19 and argue that tackling health and social inequality is likely to play a major role in solving the global diabetes pandemic and improve outcomes of COVID-19.

Association of low-level inorganic arsenic exposure from rice with age-standardized mortality risk of cardiovascular disease (CVD) in England and Wales

Adverse health outcomes, including death from cardiovascular disease (CVD), arising from chronic exposure to inorganic arsenic (iAs) are well documented. Consumption of rice is a major iAs exposure route for over 3 billion people, however, there is still a lack of epidemiological evidence demonstrating the association between iAs exposure from rice intake and CVD risks. We explored this potential association through an ecological study using data at local authority level across England and Wales. Local authority level daily per capita iAs exposure from rice (E-iAs_ing,rice) was estimated using ethnicity as a proxy for class of rice consumption. A series of linear and non-linear models were applied to estimate the association between E-iAs_ing,rice and CVD age-standardized mortality rate (ASMR), using Akaike's Information Criterion as the principle model selection criterion. When adjusted for significant confounders, notably smoking prevalence, education level, employment rate, overweight percentage, PM2.5, female percentage and medical and care establishments, the preferred non-linear model indicated that CVD risks increased with iAs exposure from rice at exposures above 0.3 μg/person/day. Also, the best-fitted linear model indicated that CVD ASMR in the highest quartile of iAs exposure (0.375-2.71 μg/person/day) was 1.06 (1.02, 1.11; p-trend <0.001) times higher than that in the lowest quartile (<0.265 μg/person/day). Notwithstanding the well-known limitations of ecological studies, this study further suggests exposure to iAs, including from rice intake, as a potentially important confounder for studies of the factors controlling CVD risks.

Candidate Gene Analysis Reveals Strong Association of CETP Variants With High Density Lipoprotein Cholesterol and PCSK9 Variants With Low Density Lipoprotein Cholesterol in Ghanaian Adults: An AWI-Gen Sub-Study

Variations in lipid levels are attributed partly to genetic factors. Genome-wide association studies (GWASs) mainly performed in European, African American and Asian cohorts have identified variants associated with LDL-C, HDL-C, total cholesterol (TC) and triglycerides (TG), but few studies have been performed in sub-Saharan Africans. This study evaluated the effect of single nucleotide variants (SNVs) in eight candidate loci (ABCA1, LCAT, LPL, PON1, CETP, PCSK9, MVK, and MMAB) on lipid levels among 1855 Ghanaian adults. All lipid levels were measured directly using an automated analyser. DNA was extracted and genotyped using the H3Africa SNV array. Linear regression models were used to test the association between SNVs and log-transformed lipid levels, adjusting for sex, age and waist circumference. In addition Bonferroni correction was performed to account for multiple testing. Several variants of CETP, LCAT, PCSK9, and PON1 (MAF > 0.05) were associated with HDL-C, LDL-C and TC levels at p < 0.05. The lead variants for association with HDL-C were rs17231520 in CETP (β = 0.139, p < 0.0001) and rs1109166 in LCAT (β = −0.044, p = 0.028). Lower LDL-C levels were associated with an intronic variant in PCSK9 (rs11806638 [β = −0.055, p = 0.027]) and increased TC was associated with a variant in PON1 (rs854558 [β = 0.040, p = 0.020]). In silico functional analyses indicated that these variants likely influence gene function through their effect on gene transcription. We replicated a strong association between CETP variants and HDL-C and between PCSK9 variant and LDL-C in West Africans, with two potentially functional variants and identified three novel variants in linkage disequilibrium in PON1 which were associated with increasing TC levels in Ghanaians.

Ethnicity and Type 2 diabetes in the UK

Type 2 diabetes is a major UK public health priority. Among minority ethnic communities, the prevalence is alarmingly high, approximately three to five times higher than in the white British population. Particularly striking is the earlier onset of Type 2 diabetes, which occurs some 10-12 years younger, with a significant proportion of cases being diagnosed before the age of 40 years. This review focuses on the UK context and Type 2 diabetes in adult populations, exploring the available evidence regarding the complex interplay of biological, lifestyle, social, clinical and healthcare system factors that are known to drive these disparities.

Ethnic distinctions in the pathophysiology of type 2 diabetes: a focus on black African-Caribbean populations

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.

Association of APOE gene polymorphism with lipid profile and coronary artery disease in Afro-Caribbeans

OBJECTIVES

Apolipoprotein E gene (APOE) polymorphism is associated with the lipid profile and cardio-vascular disease. However, these relationships vary between ethnic groups. We evaluated, for the first time in an Afro-Caribbean population, the distribution of APOE polymorphisms and their associations with coronary artery disease (CAD), the lipid profile and other cardio-metabolic risk factors.

METHODS

We studied 712 Afro-Caribbean subjects including 220 with documented CAD and 492 healthy subjects. TaqMan assays were performed to genotype rs7412 and rs429358, the two variants that determine the APOE alleles ε2, ε3 and ε4. The association between APOE genotype and the lipid profile was analysed by comparing ε2 carriers, ε3 homozygotes and ε4 carriers.

RESULTS

The frequencies of ε2, ε3 and ε4 in the overall sample were 8%, 70% and 22%, respectively. CAD was not associated with APOE polymorphism. The total cholesterol level was higher in ε4 carriers compared with ε2 carriers: 5.07 vs 4.59 mmol/L (P = 0.016). The LDL-cholesterol level was lower in APOE ε2 carriers compared with ε3 homozygotes and ε4 carriers: 2.65 vs 3.03 and 3.17 mmol/L, respectively (p = 0.002). The total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios were similar in the three allelic groups. APOE polymorphism was not associated with diabetes, hypertension, waist circumference or body mass index.

CONCLUSIONS

Our results indicate that APOE gene polymorphism is associated with the lipid profile but not with CAD in Afro-Caribbean people. This lack of association with CAD may be explained by the low atherogenic profile observed in ε4 carriers, which may warrant further investigation.

Protection from Cardiovascular Disease Due to Increased High-Density Lipoprotein Cholesterol in African Black Populations: Myth or Reality?

The burden of cardiovascular disease (CVD) in sub-Saharan Africa has increased over the last decade. Despite this, African Black populations present with relatively low incidences of coronary heart disease and ischemic heart disease, which may be attributed to their lower total cholesterol, triglycerides and low-density lipoprotein cholesterol concentrations, compared with White populations. Commensurate with these lower lipid levels, it was believed that high-density lipoprotein cholesterol (HDL-C) concentrations would be higher in Black populations compared with their White counterparts. This is based on data from previous studies of African and African American populations; however, recent studies conducted in Africa found similar or lower HDL-C concentrations in Black compared with White individuals. Current research, therefore, suggests that HDL-C may not be a good indicator of cardiovascular risk and future research should focus on HDL quality (vs quantity), by measuring HDL functionality and subclass.

Significantly greater triglyceridemia in Black African compared to White European men following high added fructose and glucose feeding: a randomized crossover trial

BACKGROUND

Black African (BA) populations are losing the cardio-protective lipid profile they historically exhibited, which may be linked with increasing fructose intakes. The metabolic effects of high fructose diets and how they relate to blood lipids are documented for Caucasians, but have not been described in BA individuals.

OBJECTIVE

The principle objective of this pilot study was to assess the independent impacts of high glucose and fructose feeding in men of BA ancestry compared to men of White European (WE) ancestry on circulating triglyceride (TG) concentrations.

METHODS

Healthy males, aged 25-60 years, of BA (n = 9) and WE (n = 11) ethnicity were randomly assigned to 2 feeding days in a crossover design, providing mixed nutrient meals with 20 % total daily caloric requirements from either added glucose or fructose. Circulating TG, non-esterified fatty acids (NEFA), glucose, insulin and C-peptide were measured over two 24-h periods.

RESULTS

Fasting TGs were lower in BAs than WEs on the fructose feeding day (p < 0.05). There was a trend for fasting TG concentrations 24 h following fructose feeding to increase in both BA (baseline median fasting: 0.80, IQR 0.6-1.1 vs 24-h median post-fructose: 1.09, 0.8-1.4 mmol/L; p = 0.06) and WE (baseline median fasting 1.10, IQR 0.9-1.5 vs 24-h median post-fructose: 1.16, IQR 0.96-1.73 mmol/L; p = 0.06). Analysis within ethnic group demonstrated that in TG iAUC was significantly higher in BA compared to WE on both glucose (35, IQR 11-56 vs -4, IQR -10-1 mmol/L/min; p = 0.004) and fructose (48, IQR 15-68 vs 13, IQR -7-38 mmol/L/min; p = 0.04). Greater suppression of postprandial NEFA was evident in WE than BA after glucose feeding (-73, IQR -81- -52 vs -26, IQR -48- -3 nmol/L/min; p = 0.001) but there was no ethnic difference following fructose feeding.

CONCLUSIONS

Understanding the metabolic effects of dietary acculturation and Westernisation that occurs in Black communities is important for developing prevention strategies for chronic disease development. These data show postprandial hypertriglyceridemia following acute feeding of high added fructose and glucose in BA men, compared to WE men, may contribute to metabolic changes observed during dietary acculturation and Westernisation.

TRIAL REGISTRATION

The study was retrospectively registered on clinicaltrials.gov: NCT02533817 .

Influence of Genetic Risk Factors on Coronary Heart Disease Occurrence in Afro-Caribbeans

BACKGROUND

Despite excessive rates of cardiovascular risk factors such as hypertension, diabetes, and obesity, Afro-Caribbeans have lower mortality rates from coronary heart disease (CHD) than do whites. This study evaluated the association of genetic risk markers previously identified in whites and CHD in Afro-Caribbeans.

METHODS

We studied 537 Afro-Caribbean individuals (178 CHD cases and 359 controls) who were genotyped for 19 CHD-related single-nucleotide polymorphisms (SNPs). A genetic risk score (GRS) incorporating the 19 SNPs was calculated. These participants were compared with 1360 white individuals from the Second Northwick Park Heart Study.

RESULTS

In Afro-Caribbeans, patients with CHD had higher rates of hypertension (78.7% vs 30.1%), hypercholesterolemia (52.8% vs 15.0%), and diabetes (53.9% vs 14.8%) and were more often men (64.0% vs 43.7%) and smokers (27.5% vs 13.4%) compared with non-CHD controls (all P < 0.001). The GRS was higher in Afro-Caribbeans with CHD than in those without CHD (13.90 vs 13.17; P < 0.001) and was significantly associated with CHD after adjustment for cardiovascular risk factors, with an odds ratio of 1.40 (95% confidence interval, 1.09-1.80) per standard deviation change. There were significant differences in allelic distributions between the 2 ethnic groups for 14 of the 19 SNPs. The GRS was substantially lower in Afro-Caribbean controls compared with white controls (13.17 vs 16.59; P < 0.001).

CONCLUSIONS

This study demonstrates that a multilocus GRS composed of 19 SNPs associated with CHD in whites is a strong predictor of the disease in Afro-Caribbeans. The differences in CHD occurrence between Afro-Caribbeans and whites might be a result of significant discrepancies in common gene variant distribution.

[Lower limb peripheral arterial disease in 268 patients in Guadeloupe]

Peripheral arterial disease of the lower limbs is a serious condition because of its local and general prognosis.

OBJECTIVES

To identify the localization of peripheral arterial disease, associated risk factors, topography and features of the disease in Guadeloupe.

PATIENTS AND METHODS

A descriptive non-interventional study was performed in Guadeloupe located in French West Indies from March to June 2014. Data for all patients, who underwent Doppler ultrasound of the lower limb in a vascular outpatient clinic and in the University Hospital in Guadeloupe for known or suspected peripheral arterial disease were included.

RESULTS

The study included 268 patients. Localizations were: infrapopliteal (n=227 patients), popliteal (n=148), femoral (n=185) and aorto-iliac (n=115). Smoking was associated with aorto-iliac (16 patients; P<0.05) and femoral (27 patients; P<0.05) localizations. Diabetes was associated with infrapopliteal localizations (133 patients; P<0.05), and high blood pressure was associated with infrapopliteal, popliteal and femoral localizations. Mean age was 73.1±10.8 years; half of patients (51 %) were women. Peripheral arterial disease was known for 52 % of the population; 147 patients were asymptomatic. Associated factors were high blood pressure (88 %), diabetes (63 %), dyslipidemia (45 %), and smoking (7 %). Ischemic heart disease was found in 14 % of patients, cerebrovascular disease in 18 % and all three localizations in 4 %. A history of amputation, bypass or endovascular treatment was found in 11 %, 20 % and 32 % of patients respectively.

CONCLUSION

In our population, an infrapopliteal site was more often found than a proximal site. Distal localization was associated with diabetes, and proximal localization with smoking. Cardiovascular risk factors exhibited an atypical pattern with a large majority of patients (88 %) having high blood pressure, two-thirds diabetes, but with very few (7 %) smokers. Peripheral arterial disease was more often associated with a history of stroke than with ischemic heart disease.

Disparities in cardiovascular disease among Caribbean populations: a systematic literature review

Background

Cardiovascular diseases (CVD) are the predominant cause of death globally. The large health disparities in the distribution of the burden of disease seen in developed and developing countries are of growing concern. Central to this concern is the poor outcome which is seen disproportionately in socially disadvantaged groups and racial/ethnic minorities. The aim of the study was to conduct a systematic literature review to investigate the nature of cardiovascular disease health disparities among Afro-Caribbean origin populations and identify current knowledge gaps.

Methods

A systematic literature review including a detailed search strategy was developed to search MEDLINE and other research databases. Using an a priori protocol peer-reviewed publications and grey literature articles were retrieved and screened and relevant data extracted by two independent review authors. Thematic analysis was done according to CVD outcomes and measures of disparity including age, sex, ethnicity and socioeconomic status.

Results

The search retrieved 665 articles of which 22 met the inclusion criteria. Most studies were conducted in the United Kingdom and centered on the prevalence of CVD by ethnicity, age and sex. An important sub-theme identified was the disparities in health service utilization/hospital admission. Coronary Heart Disease (CHD) and Peripheral Arterial Disease (PAD) were less prevalent among Afro-Caribbeans compared to Caucasian and South East Asian ethnic groups. The prevalence of CHD ranged from 0–7 % in Afro-Caribbean to 2–22 % in Caucasians. Strokes were more common among Afro-Caribbeans. There are inadequate data on morbidity and mortality from CVD, particularly across the socio-economic gradient, in Afro-Caribbean populations.

Conclusions

There are important differences in morbidity and mortality from CVD across ethnic groups. Important knowledge gaps remain in understanding the social determinants of these disparities in CVD. More research exploring these gaps by varying disparity indicators needs to be undertaken.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2166-7) contains supplementary material, which is available to authorized users.

Ethnicity and long-term vascular outcomes in Type 2 diabetes: a prospective observational study (UKPDS 83)

AIMS

Evidence of ethnic differences in vascular complications of diabetes has been inconsistent. The aim of this study was to examine the relationship between ethnicity and long-term outcome in a large sample of individuals with newly diagnosed Type 2 diabetes.

METHODS

In a prospective observational study of 4273 UK Prospective Diabetes Study participants followed for a median of 18 years, 3543 (83%) were White Caucasian, 312 (7%) Afro-Caribbean and 418 (10%) Asian Indian. Relative risks for predefined outcomes were assessed comparing Afro-Caribbean and Asian Indian with White Caucasian using accelerated failure time models, with adjustment for cardiovascular risk factors and other potentially confounding variables.

RESULTS

During follow-up, 2468 (58%) participants had any diabetes-related end point, 1037 (24%) a myocardial infarction and 401 (9%) a stroke, and 1782 (42%) died. Asian Indian were at greater risk (relative risk, 95% confidence interval) for any diabetes-related end point (1.18, 1.07-1.29), but at lower risk of all-cause mortality (0.89, 0.80-0.97) and peripheral vascular disease (0.43, 0.23-0.82), vs. White Caucasian. Afro-Caribbean participants were at lower risk for all-cause mortality (0.84, 0.76-0.93), diabetes-related death (0.75, 0.64-0.88), myocardial infarction (0.55, 0.43-0.71) and peripheral vascular disease (0.55, 0.33-0.93) vs. White Caucasian. No ethnicity-related associations were found for stroke or microangiopathy.

CONCLUSIONS

Asian Indian ethnicity is associated with the greatest burden of disease, but not with an increased risk of major vascular complications or death. Afro-Caribbean ethnicity is associated with reduced risk of all-cause and diabetes-related death, myocardial infarction and peripheral vascular disease, suggesting an ethnicity-specific protective mechanism.

The clinical characteristics at diagnosis of type 2 diabetes in a multi-ethnic population: the South London Diabetes cohort (SOUL-D)

AIMS/HYPOTHESIS

This study aimed to investigate the clinical features of newly diagnosed type 2 diabetes in an urban multi-ethnic cohort.

METHODS

A population-based cross-sectional design was used. People diagnosed with type 2 diabetes in the preceding 6 months were recruited from primary care practices in three adjacent inner-city boroughs of South London, serving a population in which 20% of residents are of black African or Caribbean ethnicity. Sociodemographic and biomedical data were collected by standardised clinical assessment and from medical records. Multiple logistic regression methods were used to report associations between ethnicity and diabetes-complication status.

RESULTS

From 96 general practices, 1,506 patients were recruited. Their mean age was 55.6 (± 11.07) years, 55% were men, 60% were asymptomatic at diagnosis and 51%, 38% and 11% were of white, black and South Asian/other ethnicity, respectively. Compared with white participants, black and South Asian/other participants were: younger (mean age 58.9 [± 10.09], 52.4 [± 11.19] and 51.5 [± 10.42] years, respectively; p < 0.0001); less likely to have neuropathy (10.1%, 3.6% and 4.4%; p < 0.0001) or report coronary artery disease (12.7%, 4.8% and 7.3%; p < 0.0001). In logistic regression, compared with white participants, black participants had lower levels of macrovascular complications (OR 0.52, 95% CI 0.32, 0.84; p = 0.01). Male sex was independently associated with microvascular disease (OR 1.69, 95% CI 1.26, 2.28; p < 0.0001).

CONCLUSIONS/INTERPRETATION

The prevalence of complications at time of diagnosis was lower than expected, especially in black and South Asian/other ethnic groups. However, in multi-ethnic inner-city populations, onset of type 2 diabetes occurred almost 10 years earlier in non-white populations than in white participants, predicating a prolonged morbidity.

Ethnic variation in the activity of lipid desaturases and their relationships with cardiovascular risk factors in control women and an at-risk group with previous gestational diabetes mellitus: a cross-sectional study

BACKGROUND

Lipid desaturase enzymes mediate the metabolism of fatty acids to long chain polyunsaturated fatty acids and their activities are related to metabolic risk factors for Type 2 diabetes (T2DM) and coronary heart disease (CHD). There are marked ethnic differences in risks of CHD and T2DM but little is known about ethnic differences in desaturase activities.

METHODS

Samples from a study of CVD risk in women with previous gestational diabetes were analysed for percentage fatty acids in plasma free fatty acid, triglyceride, cholesterol ester and phospholipid pools for 89 white European, 53 African Caribbean and 56 Asian Indian women. The fatty acid desaturase activities, stearoyl-CoA desaturase (SCD, calculated separately for C16 and C18 fatty acids), delta 6 desaturase (D6D) and delta 5 desaturase (D5D) were estimated from precursor-to-product ratios and their relationships with adiposity, blood pressure, cholesterol, triglycerides, HDL cholesterol and insulin sensitivity explored. Ethnic differences in desaturase activities independent of ethnic variation in risk factor correlates of desaturase activities were then identified.

RESULTS

There was significant ethnic variation in age, BMI, waist circumference, blood pressure, serum triglycerides and HDL cholesterol concentrations and insulin resistance. Desaturase activities showed significant correlations, independent of ethnicity, with BMI, waist circumference, triglycerides and HDL cholesterol. Independent of ethnic variation in BMI, waist circumference, triglycerides and HDL cholesterol, SCD-16 activity, calculated from each of the four lipid pools measured, was 18-35 percent higher in white Europeans than in African Caribbeans or Asian Indians (all p < 0.001). Similar, though less consistent differences were apparent for SCD-18 activity. Also independently of risk factor variation, but specifically when calculated from the cholesterol ester and phospholipid, pools, D6D activity was significantly lower in Asian Indians, and D5D activity higher in African Caribbeans.

CONCLUSIONS

Significant ethnic differences exist in desaturase activities, independently of ethnic variation in other risk factors. These characteristics did not accord with higher risk of T2DM among African Caribbeans and Asian Indians nor with lower risk of CHD among African Caribbeans but did accord with the higher risk of CHD in Asian Indians.

Insulin resistance and truncal obesity as important determinants of the greater incidence of diabetes in Indian Asians and African Caribbeans compared with Europeans: the Southall And Brent REvisited (SABRE) cohort

OBJECTIVE

To determine the extent of, and reasons for, ethnic differences in type 2 diabetes incidence in the U.K.

RESEARCH DESIGN AND METHODS

Population-based triethnic cohort. Participants were without diabetes, aged 40-69 at baseline (1989-1991), and followed-up for 20 years. Baseline measurements included fasting and postglucose bloods, anthropometry, and lifestyle questionnaire. Incident diabetes was identified from medical records and participant recall. Ethnic differences in diabetes incidence were examined using competing risks regression.

RESULTS

Incident diabetes was identified in 196 of 1,354 (14%) Europeans, 282 of 839 (34%) Indian Asians, and 100 of 335 (30%) African Caribbeans. All Indian Asians and African Caribbeans were first-generation migrants. Compared with Europeans, age-adjusted subhazard ratios (SHRs [95% CI]) for men and women, respectively, were 2.88 (95%, 2.36-3.53; P < 0.001) and 1.91 (1.18-3.10; P = 0.008) in Indian Asians, and 2.23 (1.64-3.03; P < 0.001) and 2.51 (1.63-3.87; P < 0.001) in African Caribbeans. Differences in baseline insulin resistance and truncal obesity largely attenuated the ethnic minority excess in women (adjusted SHRs: Indian Asians 0.77 [0.49-1.42]; P = 0.3; African Caribbeans 1.48 [0.89-2.45]; P = 0.13), but not in men (adjusted SHRs: Indian Asians 1.98 [1.52-2.58]; P < 0.001 and African Caribbeans, 2.05 [1.46-2.89; P < 0.001]).

CONCLUSIONS

Insulin resistance and truncal obesity account for the twofold excess incidence of diabetes in Indian Asian and African Caribbean women, but not men. Explanations for the excess diabetes risk in ethnic minority men remains unclear. Further study requires more precise measures of conventional risk factors and identification of novel risk factors.

The impact of ethnicity on objectively measured physical activity in children

Obesity and obesity-related diseases (cardiovascular disease/metabolic risk factors) are experienced differently in individuals from different ethnic backgrounds, which originate in childhood. Physical activity is a modifiable risk factor for obesity and related diseases. Both physical activity and metabolic risk factors track to adulthood, and thus understanding the physical activity patterns in children from different ethnic backgrounds is important. Given the limitations of self-report measures in children, this study provides a review of studies which have objectively measured physical activity patterns in children from different ethnic backgrounds. From a total of 16 studies, it can be concluded that physical activity does seem to vary amongst the ethnic groups especially South Asian and Black compared to White EU (European Union). The findings are less consistent for Hispanic/Mexican American children. However, there are several methodological limitations which need to be considered in future studies. Firstly, there is a need for consistency in the measurement of physical activity. Secondly, there are a range of complex factors such as socioeconomic status and body composition which affect both physical activity and ethnicity. Studies have failed to account for these differences limiting the ability to generalise that ethnicity is an independent risk factor for physical activity.

[Poorer diabetes control among the immigrant population than among the autochthonous population]

INTRODUCTION

Ethnic differences are known to exist in the prevalence of diabetes, but little is known about possible differences in the degree of diabetes control among ethnic groups. The aim of this study was to determine whether there are differences in diabetes detection and control between immigrants and the autochthonous population in our health region.

METHODS

We performed a cross-sectional, observational, population-based study of all patients diagnosed with diabetes mellitus type 2 registered and treated in 2010. We analyzed diabetes quality indicators and used multivariate logistic regression models adjusted for age, sex and number of visits. The adjustment method was forced and the absence of collinearity was identified through the ROC curve and Hosmer and Lemeshow's test.

RESULTS

There were 77,999 autochthonous patients (6,846 diabetics) and 30,748 immigrant patients (415 diabetics). A total of 8.78% of the autochthonous patients were diabetic versus 1.35% of immigrants (p <0.001). HbA1c <7.5% was found in 68.04% of the native population compared with 54.76% of immigrants. The probability of achieving optimal HbA1c control was 27% lower in immigrants (adjusted OR=0.73), while the probability of achieving good HbA1c control was 30% lower in the immigrant cohort. The model showed moderate discrimination (ROC =0.65 and Hosmer and Lemeshow's contrast, p>0.05).

CONCLUSIONS

Diabetes control and quality indicators are poorer in some immigrant groups.

The triglyceride paradox in people of African descent

Even though insulin resistance, cardiovascular disease (CVD), and type 2 diabetes (T2D) are associated with hypertriglyceridemia, blacks with these conditions usually have normal triglyceride (TG) levels. This is often called a lipid paradox. More precisely, it is a "TG paradox." The pathways that lead to hypertriglyceridemia have been intensively explored. Yet, the pathways that allow TG levels to be normal in the presence of insulin resistance have received little attention and this is problematic. Tests designed for the early detection of insulin-resistant conditions often use elevated TG levels as a diagnostic criterion. However, insulin resistance, CVD, and T2D are not usually associated with hypertriglyceridemia in people of African descent; therefore, the widespread use of TG levels to predict these conditions needs re-evaluation. This review focuses on black-white differences in: (1) the lipid profile across North America, Europe, and Africa; (2) the efficacy of TG-based screening tests, specifically the metabolic syndrome and its two abbreviated versions, the hypertriglycerdemic waist and TG/high-density lipoprotein cholesterol (HDL-C) ratio; and (3) the mechanisms that allow TG to be normal even in the presence of insulin resistance. Overall, a broader understanding of how TG physiology varies by race could lead to better diagnostic tests and improved health outcomes.

Silent myocardial ischaemia and risk factors in a diabetic Afro-Caribbean population

AIMS

In Guadeloupe, an island in the French West Indies, diabetes has a prevalence recently reported to be 10%. Myocardial ischaemia is more frequently silent in diabetics, and needs to be screened for and monitored, once identified. This study aimed to evaluate the prevalence of silent myocardial ischaemia (SMI) in a diabetic population and to analyze its associated cardiovascular risk (CVR) factors.

METHODS

This was a cross-sectional study of 147 patients with associated CVR factors, defined according to the 2004 SFC/ALFEDIAM guidelines. Exercise stress tests, myocardial performance imaging and stress echocardiography were performed. Ancova and logistic regression were used in the statistical analyses.

RESULTS

The patients' mean age was 62 years, and 53% were male. Mean duration of diabetes was 14 years. Overall, 23.1% had SMI, and these patients more frequently had a personal history of cardiovascular disease vs those without SMI. On multivariate logistic-regression analyses, the adjusted odds ratios of SMI were significantly increased in patients with a personal history of cardiovascular disease (4.36, 95% CI: 1.36-13.96; P=0.01) and left ventricular hypertrophy (LVH) (2.46, 95% CI: 1.03-5.86; P=0.04).

CONCLUSION

The prevalence of SMI in our Afro-Caribbean diabetic population was 23.1%. Searching for a personal history of cardiovascular disease and LVH may help to identify patients who need to be screened for SMI.

30 Year patterns of mortality in Tobago, West Indies, 1976-2005: impact of glucose intolerance and alcohol intake

Objectives

To determine the main predictors of all-cause and cardiovascular (CV) mortality in a rural West Indian population in Plymouth, Tobago over 30 years.

Methods

Questionnaire survey for CV risk factors and alcohol consumption patterns administered at baseline in 1976 with 92.5% response rate. 831/832 patients were followed up until 2005 or death.

Results

Hypertension (>140/90 mm Hg) was prevalent in 48% of men and 44% of women, and 21% of men and 17% of women had diabetes. Evidence showed most predictors for all cause and cardiovascular mortality having the main effects at ages <60 years, (p-value for interaction<0.01) but no risk factors having sex-specific effects on mortality. The main predictors of all-cause mortality at age <60 years in the fully adjusted model were high sessional alcohol intake (hazard ratio (HR) 2.04, 95% CI 1.10-3.80), severe hypertension >160/95 mm Hg (HR 1.68, 95% CI 1.09-2.60), diabetes (HR 3.28, 95% CI 1.89-5.69), and BMI (HR 1.04, 95% CI 1.00-1.07). The main predictors of cardiovascular mortality were similar in the fully adjusted model: high sessional alcohol intake (HR 2.47 95% CI 1.10-5.57), severe hypertension (HR 2.78 95% CI 1.56-4.95), diabetes (HR 3.68 95% CI 1.77-7.67) and additionally LVH, (HR 5.54 95% CI 1.38-22.26), however BMI did not show independent effects. For men, high sessional alcohol intake explains 27% of all cause mortality, and 40% of cardiovascular mortality at age <60 yrs. In adults aged <60 years, the attributable risk fraction for IGT/Diabetes and all cause mortality and cardiovascular mortality is 28% in women vs. 11% in men, and 22% in women vs. 6% in men respectively.

Conclusions

In this Afro-Caribbean population we found that a major proportion of deaths are attributable to high sessional alcohol intake (in males), diabetes, and hypertension and these risk factors primarily operate in those below 60 years.

Patterns of body size and adiposity among UK children of South Asian, black African-Caribbean and white European origin: Child Heart And health Study in England (CHASE Study)

BACKGROUND

The objective of this study was to examine adiposity patterns in UK South Asian, black African-Caribbean and white European children using a range of adiposity markers. A cross-sectional survey in London, Birmingham and Leicester primary schools was conducted. Weight, height, waist circumference, skinfold thickness values (biceps, triceps, subscapular and suprailiac) were measured. Fat mass was derived from bioimpedance; optimally height-standardized indices were derived for all adiposity markers. Ethnic origin was based on parental self-report. Multilevel models were used to obtain adjusted means and ethnic differences adjusted for gender, age, month, observer and school (fitted as a random effect). A total of 5887 children aged 9-10 years participated (response rate 68%), including 1345 white Europeans, 1523 South Asians and 1570 black African-Caribbeans.

RESULTS

Compared with white Europeans, South Asians had a higher sum of all skinfolds and fat mass percentage, and their body mass index (BMI) was lower. South Asians were slightly shorter but use of optimally height-standardized indices did not materially affect these comparisons. At any given fat mass, BMI was lower in South Asians than white Europeans. In similar comparisons, black African-Caribbeans had a lower sum of all skinfolds but a higher fat mass percentage, and their BMI was higher. Black African-Caribbeans were markedly taller. Use of optimally height-standardized indices yielded markedly different findings; sum of skinfolds index was markedly lower, whereas fat mass index and weight-for-height index were similar. At any given fat mass, BMI was similar in black African-Caribbeans and white Europeans.

CONCLUSIONS

UK South Asian children have higher adiposity levels and black African-Caribbeans have similar or lower adiposity levels when compared with white Europeans. However, these differences are not well represented by comparisons based on BMI, which systematically underestimates adiposity in South Asians, and in black African-Caribbeans it overestimates adiposity because of its association with height.

Ethnic differences in blood lipids and dietary intake between UK children of black African, black Caribbean, South Asian, and white European origin: the Child Heart and Health Study in England (CHASE)

BACKGROUND

Ischemic heart disease (IHD) rates are lower in UK black Africans and black Caribbeans and higher in South Asians when compared with white Europeans. Ethnic differences in lipid concentrations may play a part in these differences.

OBJECTIVE

The objective was to investigate blood lipid and dietary patterns in UK children from different ethnic groups.

DESIGN

This was a cross-sectional study in 2026 UK children (including 285 black Africans, 188 black Caribbeans, 534 South Asians, and 512 white Europeans) attending primary schools in London, Birmingham, and Leicester. We measured fasting blood lipid concentrations and collected 24-h dietary recalls.

RESULTS

In comparison with white Europeans, black African children had lower total cholesterol (-0.14 mmol/L; 95% CI: -0.25, -0.04 mmol/L), LDL-cholesterol (-0.10 mmol/L; 95% CI: -0.20, -0.01 mmol/L), and triglyceride concentrations (proportional difference: -0.11 mmol/L; 95% CI: -0.16, -0.06 mmol/L); HDL-cholesterol concentrations were similar. Lower saturated fat intakes (-1.4%; 95% CI: -1.9%, -0.9%) explained the differences between total and LDL cholesterol. Black Caribbean children had total, LDL-cholesterol, HDL-cholesterol, and triglyceride concentrations similar to those for white Europeans, with slightly lower saturated fat intakes. South Asian children had total and LDL-cholesterol concentrations similar to those for white Europeans, lower HDL-cholesterol concentrations (-0.7 mmol/L; 95% CI: -0.11, -0.03 mmol/L), and elevated triglyceride concentrations (proportional difference: 0.14 mmol/L; 95% CI: 0.09, 0.20 mmol/L); higher polyunsaturated and monounsaturated fat intakes did not explain these lipid differences.

CONCLUSIONS

Only black African children had a blood lipid profile and associated dietary pattern likely to protect against future IHD. The loss of historically lower LDL-cholesterol concentrations among UK black Caribbeans and South Asians may have important adverse consequences for future IHD risk in these groups.

The contribution of cardiovascular risk factors to peripheral arterial disease in South Asians and Blacks: a sub-study to the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study

OBJECTIVE

To determine whether differences exist in prevalence of peripheral arterial disease (PAD) between South Asians (people originating from India, Pakistan and Bangladesh) and Blacks (Black Caribbean and Black African), the two largest minority ethnic groups in the UK. To determine if associations with cardiovascular risk factors and this disease differ between these two ethnic groups.

PATIENTS AND METHODS

We recruited 572 patients (356 South Asian and 216 Blacks) > or = 45 years as a sub-study to a community screening project, the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study. All subjects completed an interviewer-led questionnaire, anthropometric measurements and blood sampling. Ankle brachial pressure index (ABPI) was calculated and intermittent claudication was assessed using the Edinburgh Claudication Questionnaire. The presence of PAD was defined as ABPI <0.9.

RESULTS

The mean age was 62 years overall with no difference between the two ethnic groups. The prevalence of PAD was 13.2% [95% confidence interval (CI) 9.7-16.7] in South Asians and 10.2% (95% CI 6.2-14.2) in Blacks with no significant difference between the two ethnic groups. The prevalence of PAD was higher in South Asian women than Black women (16.3 vs. 6.1%; P = 0.011). No difference in prevalence was found in men (11 vs. 14% P = 0.47, in South Asians and Blacks, respectively). The prevalence of intermittent claudication was 0.9% (95% CI 0.11-1.63). On multivariate logistic regression, mean systolic blood pressure, diabetes, smoking and male sex were independently associated with PAD in South Asians (P = 0.016, 0.022, 0.037 and 0.008, respectively). In Blacks, only age remained independently associated with PAD on multivariate logistic regression (P = 0.003).

CONCLUSION

The prevalence of PAD is similar in South Asians and Blacks, and similar to levels reported in pre-dominantly White populations. South Asian women had a higher prevalence of PAD than Black women, which is not explained by traditional cardiovascular risk factors.

Early emergence of ethnic differences in type 2 diabetes precursors in the UK: the Child Heart and Health Study in England (CHASE Study)

BACKGROUND

Adults of South Asian origin living in the United Kingdom have high risks of type 2 diabetes and central obesity; raised circulating insulin, triglyceride, and C-reactive protein concentrations; and low HDL-cholesterol when compared with white Europeans. Adults of African-Caribbean origin living in the UK have smaller increases in type 2 diabetes risk, raised circulating insulin and HDL-cholesterol, and low triglyceride and C-reactive protein concentrations. We examined whether corresponding ethnic differences were apparent in childhood.

METHODS AND FINDINGS

We performed a cross-sectional survey of 4,796 children aged 9-10 y in three UK cities who had anthropometric measurements (68% response) and provided blood samples (58% response); ethnicity was based on parental definition. In age-adjusted comparisons with white Europeans (n = 1,153), South Asian children (n = 1,306) had higher glycated haemoglobin (HbA1c) (% difference: 2.1, 95% CI 1.6 to 2.7), fasting insulin (% difference 30.0, 95% CI 23.4 to 36.9), triglyceride (% difference 12.9, 95% CI 9.4 to 16.5), and C-reactive protein (% difference 43.3, 95% CI 28.6 to 59.7), and lower HDL-cholesterol (% difference -2.9, 95% CI -4.5 to -1.3). Higher adiposity levels among South Asians (based on skinfolds and bioimpedance) did not account for these patterns. Black African-Caribbean children (n = 1,215) had higher levels of HbA1c, insulin, and C-reactive protein than white Europeans, though the ethnic differences were not as marked as in South Asians. Black African-Caribbean children had higher HDL-cholesterol and lower triglyceride levels than white Europeans; adiposity markers were not increased.

CONCLUSIONS

Ethnic differences in type 2 diabetes precursors, mostly following adult patterns, are apparent in UK children in the first decade. Some key determinants operate before adult life and may provide scope for early prevention.

Comparison of cardiovascular risk profiles among ethnic groups using population health surveys between 1996 and 2007

BACKGROUND

Although people of South Asian, Chinese and black ethnic backgrounds represent about 60% of the world's population, most knowledge of cardiovascular risk is derived from studies conducted in white populations. We conducted a large, population-based comparison of cardiovascular risk among people of white, South Asian, Chinese and black ethnicity living in Ontario, Canada.

METHODS

We examined the age- and sex-standardized prevalence of eight cardiovascular risk factors, heart disease and stroke among 154,653 white people, 3364 South Asian people, 3038 Chinese people and 2742 black people. For this study, we pooled respondent data from five cross-sectional health surveys conducted between 1996 and 2007: the National Population Health Survey of 1996 and the Canadian Community Health Survey, versions 1.1, 2.1, 3.1 and 4.1.

RESULTS

The four ethnic groups varied considerably in the prevalence of the four major cardiovascular risk factors that we examined: for smoking, South Asian 8.6%, Chinese 8.7%, black 11.4% and white 24.8%; for obesity, Chinese 2.5%, South Asian 8.1%, black 14.1% and white 14.8%; for diabetes mellitus, white 4.2%, Chinese 4.3%, South Asian 8.1% and black 8.5%; and for hypertension, white 13.7%, Chinese 15.1%, South Asian 17.0% and black 19.8%. The prevalence of heart disease ranged from a low of 3.2% in the Chinese population to a high of 5.2% in the South Asian population, and the prevalence of stroke ranged from a low of 0.6% in the Chinese population to a high of 1.7% in the South Asian population. Although the black population had the least favourable cardiovascular risk factor profile overall, this group had a relatively low prevalence of heart disease (3.4%).

INTERPRETATION

Ethnic groups living in Ontario had striking differences in cardiovascular risk profiles. Awareness of these differences may help in identifying priorities for the development of cardiovascular disease prevention programs for specific ethnic groups.

Comparison of the retinal microvasculature in European and African-Caribbean people with diabetes

Diabetes aggravates the impact of elevated BP (blood pressure) on the microcirculation, and people of African ancestry with diabetes are more susceptible to microvascular damage than Europeans. In the present study, we investigated possible differences in the retinal microcirculation in people of European and African-Caribbean ethnicity with diabetes that might account for this. A total of 51 subjects with Type 2 diabetes (age 40–65 years; 25 male; 29 African-Caribbean) were studied. Clinic and 24 h ambulatory BP, and fasting glucose, insulin and lipids were measured. Digital retinal images were analysed using custom-written semi-automatic software to determine: LDR (length/diameter ratio) and AVR (arteriolar/venular diameter ratio), branching angles, vessel tortuosity and NT (number of terminal vessel branches). Arterioles were narrower in European people with diabetes than in African-Caribbean people with diabetes [mean (S.D.) arteriolar diameter, 76 (7) compared with 82 (11) μm respectively (P=0.03); arteriolar LDR, 28.1 (8.5) compared with 23.7 (7.0) respectively (P=0.046); and AVR, 0.66 (0.21) compared with 0.90 (0.36) respectively (P=0.028)]. Ethnic differences in arteriolar LDR, arteriolar diameter and AVR were not explained by differences in BP, but were attenuated by adjustment for the duration of diabetes. There was no significant relationship between BP and arteriolar narrowing in the group as a whole, although the relationship between arteriolar LDR and systolic BP was stronger in Europeans than African-Caribbeans [β=0.08 (0.07) compared with β=0.03 (0.06); P=0.03]. In conclusion, in the presence of diabetes, a relationship between BP and retinal arteriolar diameter was not evident and implies impaired small artery remodelling in the presence of diabetes. African-Caribbean people with diabetes have wider retinal arterioles and this could contribute to enhanced microvascular damage in this ethnic group.

Ethnic and gender differences in physical activity levels among 9-10-year-old children of white European, South Asian and African-Caribbean origin: the Child Heart Health Study in England (CHASE Study)

BACKGROUND

Ethnic differences in physical activity in children in the UK have not been accurately assessed. We made objective measurements of physical activity in 9-10-year-old British children of South Asian, black African-Caribbean and white European origin.

METHODS

Cross-sectional study of urban primary school children (2006-07). Actigraph-GT1M activity monitors were worn by 2071 children during waking hours on at least 1 full day. Ethnic differences in mean daily activity [counts, counts per minute of registered time (CPM) and steps] were adjusted for age, gender, day of week and month. Multilevel modelling allowed for repeated days within individual and clustering within school.

RESULTS

In white Europeans, mean daily counts, CPM and mean daily steps were 394,785, 498 and 10,220, respectively. South Asian and black Caribbean children recorded more registered time per day than white Europeans (34 and 36 min, respectively). Compared with white Europeans, South Asians recorded 18 789 fewer counts [95% confidence interval (CI) 6390-31 187], 41 fewer CPM 95% CI 26-57) and 905 fewer steps (95% CI 624-1187). Black African-Caribbeans recorded 25 359 more counts (95% CI 14 273-36 445), and similar CPM, but fewer steps than white Europeans. Girls recorded less activity than boys in all ethnic groups, with 74 782 fewer counts (95% CI 66 665-82 899), 84 fewer CPM (95% CI 74-95) and 1484 fewer steps (95% CI 1301-1668).

CONCLUSION

British South Asian children have lower objectively measured physical activity levels than European whites and black African-Caribbeans.

Ethnicity and peripheral artery disease

Peripheral arterial disease (PAD) is an important healthcare problem and is an indicator of widespread atherosclerosis in other vascular territories, such as the cerebral and coronary circulations. PAD is associated with considerable morbidity and mortality. Most population-based studies investigating PAD prevalence and risk factors for its development and progression have been based on predominantly White ethnic groups. Much less is known about the characteristics of this disease in other ethnic groups. Understanding the epidemiology of PAD amongst ethnic minority groups is relevant, given that the population of minority ethnic groups in countries such as the United Kingdom rose by 53% between 1991 and 2001 and is expected to rise further in the future. This article aims to provide an overview of possible pathophysiological differences between ethnic groups for PAD, focussing predominantly on South Asians (people originating from India, Bangladesh and Pakistan) and Blacks (people of Black Caribbean and Black African descent) as these groups comprise the majority of all ethnic minorities in the United Kingdom.

[The prevalence of abnormal glucose regulation after myocardial infarction: Comparative study in two French ethnic groups]

OBJECTIVES

The aim of this study was to compare the prevalence of abnormal glucose tolerance in patients stemming from two French ethnic groups and admitted for acute coronary syndrome (ACS) to intensive coronary care unit.

MATERIALS AND METHODS

During a period of six months, 53 and 60 consecutive patients were enrolled at Fort-de-France (Martinique, French West Indies, Afrocaribbeans, group F) and at Bordeaux (France, Europeans, group B), respectively. Glucometabolic state was classified according to medical history and fasting glycemia measured from the fourth day after ACS.

RESULTS

At baseline, 36% of the patients of group F and 20% of the patients of group B had previously known diabetes (p=0.06). Prevalence of hypertension was higher in Afrocaribbeans than in Europeans (60 versus 40%, p<0.05). According to fasting glycemia, newly detected diabetes were found in six Afrocaribbeans and only one was found in Europeans; two patients in group F and three patients in group B displayed impaired fasting glycemia. As a whole, 51% of Afrocaribbeans and 27% of Europeans showed abnormal glucose tolerance (p<0.05). Furthermore, Afrocaribbeans displayed lower levels of triglycerides and higher levels of HDL cholesterol than Europeans (p<0.05).

CONCLUSION

Our study suggested a higher prevalence of impaired glucose metabolism in French Afrocaribbeans than in European counterparts after ACS. Furthermore, French Afrocaribbeans displayed a more favorable lipoprotein profile. These characteristics look like that of the American and British Afrocaribbeans, maybe because of a common genetic origin.

Mechanisms of disease: lessons from ethnicity in the role of triglyceride metabolism in ischemic heart disease

Mean risk factor levels in various ethnic groups illustrate the potential importance of triglyceride metabolism in the risk for ischemic heart disease (IHD). Serum triglyceride concentrations are a surrogate for a range of potentially atherogenic disturbances in lipoprotein species, including increased concentrations of remnants of VLDL and chylomicron metabolism, increased small, dense LDL concentrations and reduced HDL concentrations. Differences between at-risk groups in lipoprotein profiles reflect alterations in the metabolism of triglycerides that might be greater than differences observed when only circulating triglyceride concentrations are measured. This atherogenic lipoprotein profile is typically found in association with increased visceral fat, insulin resistance and type 2 diabetes and might be a characteristic of Asian Indian ethnicity. By contrast, despite being relatively insulin resistant, Afro-Caribbean men in the UK have a low risk of IHD and lack the adverse lipoprotein profile. This could result from secretion of relatively large proportions of their VLDL as small, triglyceride-poor particles, levels of which are not augmented in response to loss of insulin action. These considerations re-endorse the potential importance of triglyceride metabolism in IHD and present opportunities for identifying useful areas in which drug targets for reducing IHD risk can be sought.

Ethnicity and cardiovascular disease prevention in the United Kingdom: a practical approach to management

The United Kingdom is a diverse society with 7.9% of the population from black and minority ethnic groups (BMEGs). The causes of the excess cardiovascular disease (CVD) and stroke morbidity and mortality in BMEGs are incompletely understood though socio-economic factors are important. However, the role of classical cardiovascular (CV) risk factors is clearly important despite the patterns of these risk factors varying significantly by ethnic group. Despite the major burden of CVD and stroke among BMEGs in the UK, the majority of the evidence on the management of such conditions has been based on predominantly white European populations. Moreover, the CV epidemiology of African Americans does not represent well the morbidity and mortality experience seen in black Africans and black Caribbeans, both in Britain and in their native African countries. In particular, atherosclerotic disease and coronary heart disease are still relatively rare in the latter groups. This is unlike the South Asian diaspora, who have prevalence rates of CVD in epidemic proportions both in the diaspora and on the subcontinent. As the BMEGs have been under-represented in research, a multitude of guidelines exists for the 'general population.' However, specific reference and recommendation on primary and secondary prevention guidelines in relation to ethnic groups is extremely limited. This document provides an overview of ethnicity and CVD in the United Kingdom, with management recommendations based on a roundtable discussion of a multidisciplinary ethnicity and CVD consensus group, all of whom have an academic interest and clinical practice in a multiethnic community.

Increased high sensitivity C-reactive protein and neutrophil count are related to increased standard cardiovascular risk factors in healthy Chinese men

BACKGROUND

Epidemiologic data regarding the role of inflammation in atherosclerosis have been based mainly on Caucasian populations. Thus, we analyzed the cross-sectional relationships of inflammatory biomarkers to cardiovascular risk factors (CVRF) and related variables in a large group of healthy Chinese men, a population with a markedly lower heart disease mortality rate compared with Western populations.

METHODS

The study consisted of 8374 men aged 20-80 who attended a voluntary health examination at a metropolitan university center between 1997 and 2002. The relationships between serum high sensitivity C-reactive protein (hsCRP), total white blood cell (WBC), neutrophil, and monocyte counts to CVRF were analyzed using multivariate linear and logistic regression analyses. Whether a dose-response effect existed between elevated levels of each marker and increasing numbers of CVRF was also evaluated.

RESULTS

The distribution of hsCRP was similar to Western studies. Both multivariate regression analyses showed all four markers to have significant correlations with body mass index, triglycerides, and adverse high density lipoprotein/low density lipoprotein ratio. Smoking was associated with increased levels of all four markers. Elevated neutrophil count had the most markedly progressive dose-response effect with increasing numbers of CVRF, whereas elevated monocyte count showed a drop in risk with CVRF of five and above.

CONCLUSION

We show in our study that with increasing numbers of standard CVRF, healthy Chinese men have progressive and increasing risks of having elevated levels of hsCRP, total WBC, and neutrophil counts. While the inflammatory markers surveyed were largely correlated with CVRF, the similar values of CRP between populations with divergent mortality rates suggest that a more complex relationship may exist between CRP and disease outcome. The possible utility of neutrophil count as a marker for cardiovascular disease risk in healthy men awaits further evaluation in prospective studies.

Microalbuminuria and coronary heart disease risk in an ethnically diverse UK population: a prospective cohort study

Microalbuminuria (MA) is a strong risk factor for subsequent chronic disease, both renal and coronary heart disease (CHD), in European origin populations, but CHD risks differ by ethnicity, and it was hypothesized that prevalence of MA and relations with CHD may also differ. Combined analyses of two population-based cohorts started in 1988 and consisted of 1460 Europeans (70% male), 946 South Asians (78% male), and 559 African Caribbeans (51% male) who resided in London and were aged 40 to 69. Baseline fasting blood, overnight urine collection, and clinical measurements were performed. Prevalent CHD was defined by clinical history or major electrocardiogram changes. Age-adjusted albumin excretion rates (AER; geometric means, mug/min) were significantly higher in African Caribbeans (men: 6.1, 95% confidence interval [CI] 5.5 to 6.7; women: 5.7, 95% CI 5.2 to 6.2) than in South Asians (men: 4.3, 95% CI 4.0 to 4.5; women 3.4, 95% CI 3.0 to 3.8) and Europeans (men: 4.5, 95% CI 4.3 to 4.8; women: 3.3, 95% CI 3.1 to 3.6). MA was associated with both prevalent CHD and CHD mortality in South Asian men (hazard ratio 2.5; 95% CI 1.3 to 4.8) and in European women (hazard ratio 13.0; 95% CI 2.6 to 64.2) but not in any other group. Greater AER in African Caribbeans and the absence of association with CHD contrast with lower AER in South Asian men and European women, both strongly associated with CHD prevalence and mortality. These differences suggest that the pathogenesis of kidney disease and its link with CHD differ by ethnicity and gender.

Novel serologic markers of cardiovascular risk

New serologic markers of cardiovascular risk continue to be amassed. Among the new markers, C-reactive protein, fibrinogen, and homocysteine have enjoyed the most acceptance, but newer concepts such as inflammatory cytokines, aspirin resistance, and antioxidant deficiency continue to emerge. Traditional cardiac risk factors are able to predict less than half of cardiovascular events, and the new array of markers have added little to clinical practice, with their use and significance remaining unclear. This article analyzes the new serologic markers of risk in light of the mechanistic, epidemiologic, and clinical data collected over the past decade, and in so doing provides a comprehensive understanding of their role.

Metabolic syndrome and coronary heart disease in South Asians, African-Caribbeans and white Europeans: a UK population-based cross-sectional study

AIMS/HYPOTHESIS

The aim of this study was to study differences in the prevalence of the metabolic syndrome and its associations with prevalent CHD according to ethnicity and sex.

METHODS

We performed a combined analysis of two population-based cross-sectional studies conducted between 1988 and 1991 that followed identical protocols. Participants (aged 40-69 years) comprised 2,346 Europeans (76% male), 1,711 South Asians (83% male) and 803 African-Caribbeans (57% male) resident in west London. Fasting blood, overnight urine collection, clinical and anthropometric measurements were performed. Clinical history or major ECG changes defined prevalent CHD. The metabolic syndrome was defined according to the criteria recommended by the World Health Organization (WHO) and the National Cholesterol Education Programme (NCEP).

RESULTS

The prevalence of the metabolic syndrome was highest in South Asians (WHO, men 46%, women 31%; NCEP, men 29%, women 32%) and lowest in European women (WHO, 9%; NCEP, 14%). The prevalence of CHD was 10% in South Asian men, 9% in European men, 5-6% in African-Caribbeans and European women, and 2% in South Asian women. The metabolic syndrome was associated with prevalent CHD in European men [NCEP, odds ratio (OR)=1.6, 95% CI 1.2-2.4; WHO, OR=1.7, 95% CI 1.2-2.5] and South Asian men (NCEP, OR=2.1, 95% CI 1.5-3.1; WHO, OR=1.6, 95% CI 1.1-2.3). Associations with CHD were weaker in African-Caribbeans and were inconsistent among European women.

CONCLUSIONS/INTERPRETATION

The current definitions of the metabolic syndrome give an inconsistent picture of cardiovascular disease risk when applied to different ethnic groups within the UK. Prospective studies are needed to validate workable ethnic-specific definitions.

Ethnic differences in skin microvascular function and their relation to cardiac target-organ damage

BACKGROUND

People of Black African descent have increased risks of vascular target-organ damage not explained by greater blood pressures.

OBJECTIVE

To study ethnic differences in the microvasculature.

DESIGN AND METHODS

Flow (flux) in microcirculatory skin vessels was assessed using laser Doppler fluximetry in 181 Afro-Caribbean and European men and women aged 40-65 years from the general population in London, UK. Flux in response to maximal heating (maximal hyperaemic response) was measured and minimum vascular resistance calculated. Peak flux and time to peak after an ischaemic stimulus were also measured. Target-organ damage was assessed using echocardiographic interventricular septal thickness (IVST).

RESULTS

In men, maximum hyperaemic response was attenuated in Afro-Caribbeans [109 arbitrary units (au), 25th and 75th percentiles 101, 117] compared with Europeans [165 (155, 179) au; P = 0.008]. Minimum vascular resistance was greater in Afro-Caribbeans, significantly so in men [(1.22 (1.18, 1.28) au/mmHg compared with 0.80 (0.77, 0.83) au/mmHg; P = 0.006]. Peak ischaemic response was attenuated in Afro-Caribbean men and women compared with Europeans (35.6 au compared with 49.5 au; P < 0.001) and time to peak was prolonged (14.1 s compared with 12.5 s; P = 0.07). These ethnic differences could not be accounted for by standard cardiovascular risk factors. IVST was greater in Afro-Caribbeans than in Europeans. Minimum vascular resistance and peak response accounted for a small proportion of this ethnic difference, in addition to conventional factors.

CONCLUSIONS

Afro-Caribbeans have poorer microvascular structure and function, unexplained by conventional risk factors, which may contribute to greater rates of vascular target-organ damage.

Ethnic differences in vascular stiffness and relations to hypertensive target organ damage

OBJECTIVE

People of Black African descent have greater risks of hypertensive target organ damage than would be anticipated for given levels of blood pressure. Arterial stiffness may further account for ethnic differences in risk.

DESIGN

Cross-sectional study.

SETTING

Population based, London, UK.

PARTICIPANTS

One hundred and three Europeans and 99 African Caribbeans aged 40-64 years.

METHODS

We measured resting and ambulatory blood pressure, and pulse wave velocity (PWV) of elastic and muscular arteries. Echocardiography measured interventricular septal thickness (IVST).

MAIN OUTCOME MEASURES

PWV, IVST.

RESULTS

Carotid-femoral PWV was 12.7 m/s [95% confidence interval (CI) 12.3, 13.1] in African Caribbeans and 11.2 m/s (10.9, 11.6) in Europeans (P < 0.0001). This difference persisted on adjustment for resting and ambulatory blood pressure, 12.4 versus 11.5 m/s (P = 0.003). The greater IVST in African Caribbeans (9.6 mm) compared to Europeans (9.1 mm, P = 0.0005), could only in part be accounted for by differences in carotid*femoral PWV. Stiffness in the muscular carotid-radial segment did not differ by ethnicity, but was positively associated with systolic pressure in Europeans (beta regression coefficient 0.033, P = 0.04), and negatively associated in African Caribbeans (-0.036, P = 0.04, and P = 0.02 for interaction).

CONCLUSIONS

Aortic stiffness is increased in African Caribbeans compared to Europeans, even when higher blood pressures are accounted for. It is most closely related to IVST, but contributes little to explaining ethnic differences. Stiffness of the upper limb muscular arteries did not differ by ethnicity, but remained favourable in the presence of hypertension in African Caribbeans, while being increased in Europeans. We suggest that this is due to ethnic differences in vascular remodelling.

Evaluation of equity in diabetes health care in relation to African and Caribbean ethnicity

OBJECTIVE

Many US studies have shown that ethnic minority groups have less access to health care. We evaluated whether black African and black Caribbean people with diabetes in the UK gain access to diabetes health care on an equitable basis compared with white people.

DESIGN

Cross-sectional questionnaire survey set in 29 general practices in south London. Main measures were self-reported morbidity, SF-36 scores and utilisation of health care. Analyses of utilisation variables were adjusted for age, sex, ethnic group, duration of diabetes, and socio-economic and health status.

RESULTS

There were 1,899 respondents (64%) from 2,983 individuals registered with diabetes. These included 799 white, 522 black Caribbean, 163 black African and 415 other subjects with type 2 diabetes. After adjusting for need, black Caribbeans reported higher utilisation of health care than white subjects for four of nine utilisation variables, and black Africans for two. For the remaining variables utilisation was equivalent in different ethnic groups. Black Caribbean subjects were more likely to be treated for hypertension if hypertensive (odds ratio 1.84, 95% CI 1.05 to 3.22), to use blood or urine self-monitoring (1.40, 1.04 to 1.88) and to have attended a diabetes nurse (1.34, 1.04 to 1.74) or dietician (1.49, 1.19 to 1.86). Black Africans were more likely to have attended a dietician (2.15, 1.40 to 3.29) or an ophthalmologist (1.72, 1.10 to 2.70) in the past year.

CONCLUSION

There was no evidence from this study that black African or black Caribbean subjects had less access to diabetes health care in relation to need.

Lipoprotein lipase gene polymorphisms in Croatian patients with coronary artery disease

Modifications in lipoprotein lipase levels lead to elevated triglycerides and reduced high density lipoprotein (HDL), both of which are risk factors for coronary artery disease (CAD). Hence, we examined the influence of the -93T/G, D9N, N291S, and S447X polymorphisms in the lipoprotein lipase (LPL) gene on CAD risk and lipid levels in Croatian patients with and without angiographically confirmed CAD. The N291S polymorphism was significantly associated with CAD (OR = 0.36; 95% CI = 0.13, 0.99; p = 0.048). This association was only moderately affected by adjusting for various lipids (OR = 0.36; 95% CI = 0.12, 1.08; p = 0.068). HDL2-cholesterol and apolipoprotein A-I levels were significantly higher in non-carriers of the -93T/G and D9N polymorphisms in the CAD group (p = 0.017 and 0.028, respectively). The N291S genetic variant did not show any significant difference between carriers and non-carriers in either group studied for any of the lipids. Lower triglyceride and higher HDL2-cholesterol levels in the control group were associated with carriers of the S447X mutation (p = 0.043 and 0.056, respectively). LPL gene polymorphisms might be involved in predisposition to CAD and determination of lipid profiles.

Cross-reactivity of anti-CagA antibodies with vascular wall antigens: possible pathogenic link between Helicobacter pylori infection and atherosclerosis

BACKGROUND

Helicobacter pylori-CagA positive strains have been shown to be associated with atherosclerosis. However, the pathogenesis is still undetermined. The aim of this study was to determine whether anti-CagA antibodies cross-react with antigens of normal and atherosclerotic arteries.

METHODS AND RESULTS

Eight umbilical cord sections, 14 atherosclerotic artery sections, and 10 gastrointestinal tract sections were examined by immunohistochemistry using polyclonal anti-CagA antibodies. Five atherosclerotic and 3 normal artery samples were also lysed in ice-cold lysis buffer containing protease inhibitors and were immunoprecipitated using the same antibodies. Anti-CagA antibodies reacted with cytoplasm and nuclei of smooth muscle cells in umbilical cord and atherosclerotic vessel sections, cytoplasm of fibroblasts-like cells in intimal atherosclerotic plaques, and the cell membranes of endothelial cells. Anti-CagA antibodies also specifically immunoprecipitated 2 high molecular weight antigens of 160 and 180 kDa from both normal and atherosclerotic artery lysates.

CONCLUSIONS

Anti-CagA antibodies cross-react with antigens of both normal and atherosclerotic blood vessels. We speculate that the binding of anti-CagA antibodies to those antigens in injured arteries could influence the progression of atherosclerosis in CagA-positive H pylori-infected patients.

Ethnic differences in carotid and left ventricular hypertrophy

OBJECTIVES

Afro-Caribbean subjects have a higher prevalence of hypertension, a lower prevalence of ischaemic heart disease and a higher premature mortality compared to White Europeans. Left ventricular hypertrophy (LVH) is also more prevalent in Afro-Caribbeans even at similar levels of blood pressure. It is widely believed that carotid artery intima-media thickening (IMT) represents an early marker for the development of atheroma, and carotid IMT and LVH are associated in White populations. Whether the relationship between carotid IMT and LVH is similar in Black subjects is unknown.

METHODS

Thirty-eight subjects were studied using carotid and femoral ultrasonography and echocardiography; 19 Afro-Caribbean and 19 White European subjects were matched for age, sex and mean 24 h systolic blood pressure.

RESULTS

The Afro-Caribbean group had a significantly greater left ventricular mass index (LVMI) compared to the White European: 136.4 +/- 6.1 versus 112.4 +/- 6.2 g/m2, P < 0.01. However, carotid IMT, carotid diameter, femoral IMT and femoral diameter were similar between the groups: 0.75 +/- 0.02 versus 0.77 +/- 0.04 mm, 6.54 +/- 0.15 versus 6.56 +/- 0.16 mm, 0.66 +/- 0.03 versus 0.68 +/- 0.03 mm and 8.40 +/- 0.33 versus 8.25 +/- 0.23 mm, respectively.

CONCLUSIONS

Afro-Caribbean subjects with similar blood pressures have similar mean carotid and femoral IMTs compared to White Europeans, in spite of marked differences in LVMI. Whether this reflects a discrepancy in the degree of cardiovascular risk for similar levels of LVMI or whether this is a reflection of an altered pattern of target organ damage associated with hypertension in Afro-Caribbean subjects is unclear.