Do known risk factors explain the higher coronary heart disease mortality in South Asian compared with European men? Prospective follow-up of the Southall and Brent studies, UK

Presence of coronary artery disease in diabetic and non diabetic South Asian immigrants

Introduction

South Asian Immigrants (SAIs) are the second fastest growing Asian immigrant population in the US, and at a higher risk of type 2 diabetes (diabetes) and coronary artery disease (CAD) than the general US population. Objectives: We sought to determine in SAIs the; 1) the prevalence of CAD risk factors in diabetics and non-diabetics; and b) the high possibility of CAD in diabetic SAIs. We also assessed the prevalence of sub-clinical CAD in both diabetics and non-diabetics SAIs using common carotid artery Intima-media thickness (CIMT) as a surrogate marker for atherosclerosis.

Methods

In a cross-sectional study design, 213 first generation SAIs were recruited and based on the history, and fasting glucose levels were divided into two subgroups; 35 diabetics and 178 non-diabetics. 12-hour fasting blood samples were collected for glucose and total cholesterol levels. Exercise Tolerance Test (ETT) was performed to determine the possibility of CAD.

Results

Both diabetics and non-diabetics SAIs in general, share a significant burden of CAD risk factors. The prevalence of hypertension (p = 0.003), total cholesterol ≥ 200 mg/dl (p < 0.0001) and family history of diabetes (p < 0.0001) was significantly was significantly higher in diabetics compared to non-diabetics. Of the 22/29 diabetic participants without known history of CAD, 45% had positive ETT (p < 0.001). Similarly, 63.1% of diabetics and 51.8 % of non-diabetics were positive for sub-clinical CAD using CIMT as a marker.

Conclusion

The susceptibility to diabetes amongst SAIs promotes an adverse CAD risk, as evident by this small study. Further research, including larger longitudinal prospective studies, is required to validate the current small study findings with investigation of the temporal association.

Coronary atherosclerotic plaque burden and composition by CT angiography in Caucasian and South Asian patients with stable chest pain

AIMS

South Asian (SA) patients are known to have an increased incidence of acute cardiovascular events compared with Caucasians. The aim of this observational study was to compare the prevalence of coronary stenoses, the amount and composition of coronary atherosclerosis in a cohort of Caucasian and SA patients with stable chest pain, in non-acute settings.

METHODS AND RESULTS

The study protocol conformed to the ethical guidelines of the 1975 Declaration of Helsinki. In 963 consecutive Caucasian and SA patients undergoing coronary computed tomography angiography, atherosclerotic plaques were quantified using a semi-automated algorithm. The vessel per cent diameter and area stenosis were measured. Plaque composition was examined from the measurement of calcified, non-calcified, and total plaque burden. There were 420 Caucasian (238 males) and 543 SA (297 males) patients. Caucasian patients were older than SA patients (54.39 ± 11.65 vs. 49.83 ± 11.03 years) and had lower prevalence of diabetes (13.13 vs. 32.41%) and hyperlipidaemia (56.90 vs. 68.51%) (all P-values <0.001). After adjusting for differences in cardiovascular risk factors, there were no differences in per cent diameter and area stenosis, and no difference in the proportions of patients with one-, two-, or three-vessel disease. There was no difference in total plaque burden; however, the per cent non-calcified plaque composition was lower in Caucasians compared with SA (80.95 vs. 90.42%; P-value <0.001).

CONCLUSION

This study conducted in non-acute settings showed an ethnic difference in composition of coronary atherosclerotic plaque with lower non-calcified composition in Caucasian patients compared with SA patients, which was independent of age, diabetes, hyperlipidaemia, and the other available cardiovascular risk factors.

Using nationwide ‘big data’ from linked electronic health records to help improve outcomes in cardiovascular diseases: 33 studies using methods from epidemiology, informatics, economics and social science in the ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER) programme

Background

Electronic health records (EHRs), when linked across primary and secondary care and curated for research use, have the potential to improve our understanding of care quality and outcomes.

Objective

To evaluate new opportunities arising from linked EHRs for improving quality of care and outcomes for patients at risk of or with coronary disease across the patient journey.

Design

Epidemiological cohort, health informatics, health economics and ethnographic approaches were used.

Setting

230 NHS hospitals and 226 general practices in England and Wales.

Participants

Up to 2 million initially healthy adults, 100,000 people with stable coronary artery disease (SCAD) and up to 300,000 patients with acute coronary syndrome.

Main outcome measures

Quality of care, fatal and non-fatal cardiovascular disease (CVD) events.

Data platform and methods

We created a novel research platform [ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER)] based on linkage of four major sources of EHR data in primary care and national registries. We carried out 33 complementary studies within the CALIBER framework. We developed a web-based clinical decision support system (CDSS) in hospital chest pain clinics. We established a novel consented prognostic clinical cohort of SCAD patients.

Results

CALIBER was successfully established as a valid research platform based on linked EHR data in nearly 2 million adults with > 600 EHR phenotypes implemented on the web portal (seehttps://caliberresearch.org/portal). Despite national guidance, key opportunities for investigation and treatment were missed across the patient journey, resulting in a worse prognosis for patients in the UK compared with patients in health systems in other countries. Our novel, contemporary, high-resolution studies showed heterogeneous associations for CVD risk factors across CVDs. The CDSS did not alter the decision-making behaviour of clinicians in chest pain clinics. Prognostic models using real-world data validly discriminated risk of death and events, and were used in cost-effectiveness decision models.

Conclusions

Emerging ‘big data’ opportunities arising from the linkage of records at different stages of a patient’s journey are vital to the generation of actionable insights into the diagnosis, risk stratification and cost-effective treatment of people at risk of, or with, CVD.

Future work

The vast majority of NHS data remain inaccessible to research and this hampers efforts to improve efficiency and quality of care and to drive innovation. We propose three priority directions for further research. First, there is an urgent need to ‘unlock’ more detailed data within hospitals for the scale of the UK’s 65 million population. Second, there is a need for scaled approaches to using EHRs to design and carry out trials, and interpret the implementation of trial results. Third, large-scale, disease agnostic genetic and biological collections linked to such EHRs are required in order to deliver precision medicine and to innovate discovery.

Study registration

CALIBER studies are registered as follows: study 2 – NCT01569139, study 4 – NCT02176174 and NCT01164371, study 5 – NCT01163513, studies 6 and 7 – NCT01804439, study 8 – NCT02285322, and studies 26–29 – NCT01162187. Optimising the Management of Angina is registered as Current Controlled Trials ISRCTN54381840.

Funding

The National Institute for Health Research (NIHR) Programme Grants for Applied Research programme (RP-PG-0407-10314) (all 33 studies) and additional funding from the Wellcome Trust (study 1), Medical Research Council Partnership grant (study 3), Servier (study 16), NIHR Research Methods Fellowship funding (study 19) and NIHR Research for Patient Benefit (study 33).

Longitudinal study of cardiometabolic risk from early adolescence to early adulthood in an ethnically diverse cohort

OBJECTIVE

To examine influences of adiposity from early adolescence to early 20s on cardiovascular disease (CVD) risk in the multiethnic Determinants of young Adult Social well-being and Health (DASH) longitudinal study.

METHODS

In 2002-2003, 6643 11-13-year-olds from 51 London schools participated at baseline, and 4785 were seen again at 14-16 years. Recently, 665 (97% of invited) participated in pilot follow-up at 21-23 years, with biological and psychosocial measures and blood biomarkers (only at 21-23 years). Regression models examined interplay between ethnicity, adiposity and CVD.

RESULTS

At 21-23 years, ∼30-40% were overweight. About half of the sample had completed a degree with little ethnic variation despite more socioeconomic disadvantage in adolescence among ethnic minorities. Regardless of ethnicity, overweight increased more steeply between 14-16 years and 21-23 years than between 11-13 years and 14-16 years. More overweight among Black Caribbean and Black African females, lower systolic blood pressure (sBP) among Indian females and Pakistani/Bangladeshi males compared with White UK peers, persisted from 11-13 years. At 21-23 years, glycated haemoglobin (HbA1c) was higher among Black Caribbean females, total cholesterol higher and high-density lipoprotein (HDL) cholesterol lower among Pakistani/Bangladeshis. Overweight was associated with a ∼+2 mm Hg rise in sBP between 11-13 years and 21-23 years. Adiposity measures at 11-13 years were related to allostatic load (a cluster of several risk markers), HbA1c and HDL cholesterol at 21-23 years. Ethnic patterns in CVD biomarkers remained after adjustments.

CONCLUSIONS

Adolescent adiposity posed significant risks at 21-23 years, a period in the lifespan generally ignored in cardiovascular studies, when ethnic/gender variations in CVD are already apparent.

The association of duration of residence in the United States with cardiovascular disease risk factors among South Asian immigrants

South Asians are disproportionately impacted by cardiovascular disease (CVD). Our objective was to examine the association between duration of residence in the US and CVD risk factors among South Asian adult immigrants. Multivariate logistic regression analyses using pooled data from the 2005, 2007, 2009 California Health Interview Surveys. Duration of residence in the US < 15 years was significantly associated with overweight/obese BMI (OR 0.59; 95% CI 0.35, 0.98 for 5 to < 10 years), daily consumption of 5+ servings of fruits/vegetables (OR 0.37; 95% CI 0.15, 0.94 for 10 to < 15 years), and sedentary lifestyle (OR 2.11; 95% CI 1.17, 3.81 for 10 to < 15 years) compared with duration of residence ≥ 15 years after adjusting for illness burden, healthcare access, and socio-demographic characteristics. Duration of residence was not significantly associated with other CVD risk factors. Duration of residence is an important correlate of overweight/obesity and other risk factors among South Asian immigrants.

Ethnic differences in coronary plaque and epicardial fat volume quantified using computed tomography

Epidemiological studies observed a higher prevalence of coronary atherosclerosis in South Asians when compared to Caucasians, but quantitative computed tomography differences in aggregate plaque volume (APV) and epicardial fat volume (EFV) between South Asians, Southeast or East Asians (SEEAs) and Caucasians remain unknown. We aimed to compare APV and EFV quantified on computed-tomographic-coronary-angiography (CTCA) between South Asian, SEEA and Caucasian populations residing in Australia. Age, gender and body-mass-index matched subjects from three ethnic groups who underwent clinically indicated 320-detector CTCA were retrospectively analysed. Percentage APV in the first 5 cm of the left anterior descending artery (LAD) and EFV were quantified using dedicated software (Vital Images, USA). One-hundred-and-fifty subjects (average age = 57.7 years, 56 % male, n = 50 in each ethnic group) were analysed. Mean LAD percentage APV was highest in South Asians (44.5 ± 8.4 % vs. 37.5 ± 6.5 % in SEEAs and 39.5 ± 6.4 % in Caucasians, P = 0.00001). South Asian ethnicity predicted LAD APV above traditional risk factors on multivariate analysis (P = 0.000002). EFV was significantly higher in both South Asians (103.2 ± 41.7 cm³ vs. 85.8 ± 39.4 cm³, P = 0.035) and SEEAs (110.8 ± 36.9 cm³ vs. 85.8 ± 39.4 cm³, P = 0.001) when compared with Caucasians. In this cohort LAD percentage APV and EFV, as quantified on CTCA, differs between South Asians, SEEA and Caucasian populations, with higher LAD APV observed in South Asians and lower EFV in Caucasians. Atherosclerotic volume in LAD was best predicted by South Asian ethnicity above traditional risk factors and EFV. Further research is required to establish whether APV and EFV quantification can improve cardiac risk prediction in the South Asian population.

Physical Activity During the Early Years: A Systematic Review of Correlates and Determinants

CONTEXT

Being physically active during the early years (age 0-6 years) is vital for healthy development. Identifying correlates and determinants of physical activity (PA) is crucial to guide effective interventions. This systematic review synthesized studies investigating potential correlates and determinants of PA during the early years, accounting for different types of PA assessment.

EVIDENCE ACQUISITION

Nine electronic databases were searched from inception year (1900) until September 2014; data were analyzed/interpreted in April 2015. The following inclusion criteria were used: written in English, published in peer-reviewed journals, participants not in statutory/school education, and an observational design investigating associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total, moderate to vigorous, and light PA were reported using an ecologic model.

EVIDENCE SYNTHESIS

Of 22,045 identified studies, 130 were included. All took place in high-income countries and few (6%) were of high quality. Correlates of total PA were sex (male, ++); parental PA (+); parental support (+); and time outdoors (+). Determinants of total PA were sex (+) and time spent playing with parents (+). The only correlate of moderate to vigorous PA was sex (male, ++). No determinants of moderate to vigorous or light PA were found. PA correlates/determinants were relatively consistent between objective and subjective PA measures.

CONCLUSIONS

Numerous studies investigated potential correlates and determinants of PA, but overall quality was low. A small number of demographic/biological and social/cultural factors were associated with PA. There is a need for high-quality studies exploring correlates/determinants across all domains of the ecologic model.

HDL functionality in South Asians as compared to white Caucasians

BACKGROUND AND AIMS

South Asians have an exceptionally high risk of developing cardiovascular disease compared to white Caucasians. A contributing factor might be dysfunction of high density lipoprotein (HDL). We aimed to compare HDL function in different age groups of both ethnicities.

METHODS AND RESULTS

HDL functionality with respect to cholesterol efflux, anti-oxidation and anti-inflammation was determined using fasting, apoB-depleted, plasma samples from South Asian and white Caucasian neonates (n = 14 each), adolescent healthy men (n = 12 each, 18-25 y), and adult overweight men (n = 12 each, 40-50 y). Adolescents were subjected to a 5-day high fat high calorie diet (HCD) and adults to an 8-day very low calorie diet (LCD). Additionally, HDL composition was measured in adolescents and adults using (1)H-NMR spectroscopy. Anti-oxidative capacity was lower in South Asian adults before LCD (19.4 ± 2.1 vs. 25.8 ± 1.2%, p = 0.045, 95%-CI = [0.1; 12.7]) and after LCD (16.4 ± 2.4 vs. 27.6 ± 2.7%, p = 0.001, 95%-CI = [4.9; 17.5]). Anti-inflammatory capacity was reduced in South Asian neonates (23.8 ± 1.2 vs. 34.9 ± 1.3%, p = 0.000001, 95%-CI = [-14.6; -7.5]), and was negatively affected by an 8-day LCD only in South Asian adults (-12.2 ± 4.3%, p = 0.005, 95%-CI = [-5.9; -1.2]). Cholesterol efflux capacity was increased in response to HCD in adolescents (South Asians: +6.3 ± 2.9%, p = 0.073, 95%-CI = [-0.02; 0.46], Caucasians: +11.8 ± 3.4%, p = 0.002, 95%-CI = [0.17;0.65]) and decreased after LCD in adults (South Asians: -10.3 ± 2.4%, p < 0.001, 95%-CI = [-0.57; -0.20], Caucasians: -13.7 ± 1.9%, p < 0.00001, 95%-CI = [-0.67; -0.33]). Although subclass analyses of HDL showed no differences between ethnicities, cholesterol efflux correlated best with cholesterol and phospholipid within small HDL compared to other HDL subclasses and constituents.

CONCLUSION

Impaired HDL functionality in South Asians may be a contributing factor to their high CVD risk.

CLINICAL TRIAL REGISTRATION

NTR 2473 (URL: http://www.trialregister.nl/).

Urbanized South Asians' susceptibility to coronary heart disease: The high-heat food preparation hypothesis

OBJECTIVE

Known risk factors do not fully explain the comparatively high susceptibility to coronary heart disease (CHD) in South Asians (Indian, Pakistani, Bangladeshi, and Sri Lankan populations in South Asia and overseas). The search for explanatory hypotheses and cofactors that raise susceptibility of South Asians to CHD continues. The aim of this study was to propose "the high-heat food preparation hypothesis," where neo-formed contaminants (NFCs) such as trans-fatty acids (TFAs) and advanced glycation end-products (AGEs) are the cofactors.

METHODS

We reviewed the actions of AGEs and TFAs, the burden of these products in tissues and blood in South Asians, the relationship between these products and CHD, the effects of preparing food and reheating oils at high temperatures on NFCs, and the foods and mode of preparation in South Asian and Chinese cuisines.

RESULTS

Animal and human studies show NFCs increase the risk for CHD. Evidence on the consumption and body burden of these products across ethnic groups is not available, and comparable data on the NFC content of the cuisine of South Asians and potential comparison populations (e.g., the Chinese with lower CHD rates) are limited. South Asians' cuisine is dominated by frying and roasting techniques that use high temperatures. South Asian foods have high TFA content primarily through the use of partially hydrogenated fats, reheated oils, and high-heat cooking. Reheating oils greatly increases the TFA content. In comparison, Chinese cuisine involves mostly braising, steaming, and boiling rather than frying.

CONCLUSION

We hypothesize that South Asians' susceptibility to CHD is partly attributable to high-heat treated foods producing high NFCs. Research to accrue direct evidence is proposed.

Diabetes mellitus and its complications in India

India is one of the epicentres of the global diabetes mellitus pandemic. Rapid socioeconomic development and demographic changes, along with increased susceptibility for Indian individuals, have led to the explosive increase in the prevalence of diabetes mellitus in India over the past four decades. Type 2 diabetes mellitus in Asian Indian people is characterized by a young age of onset and occurrence at low levels of BMI. Available data also suggest that the susceptibility of Asian Indian people to the complications of diabetes mellitus differs from that of white populations. Management of this disease in India faces multiple challenges, such as low levels of awareness, paucity of trained medical and paramedical staff and unaffordability of medications and services. Novel interventions using readily available resources and technology promise to revolutionise the care of patients with diabetes mellitus in India. As many of these challenges are common to most developing countries of the world, the lessons learnt from India's experience with diabetes mellitus are likely to be of immense global relevance. In this Review, we discuss the epidemiology of diabetes mellitus and its complications in India and outline the advances made in the country to ensure adequate care. We make specific references to novel, cost-effective interventions, which might be of relevance to other low-income and middle-income countries of the world.

Genetic epidemiology of coronary artery disease: an Asian Indian perspective

Coronary artery disease (CAD) has emerged as a major cause of morbidity and mortality worldwide. Recent findings on the role of genetic factors in the aetiopathology of CAD have implicated novel genes and variants in addition to those involved in lipid and lipoprotein metabolism. However, our present knowledge is limited due to lack of clarity on their exact identity and the quantum of impact on disease susceptibility, and incident risk. It is a matter of great interest to understand the role of genetic factors in ethnic populations that have a strong underlying predisposition to CAD such as the South Asian populations, particularly among Asian Indians living in India and abroad. Although, a number of isolated studies do implicate certain gene polymorphisms towards enhanced disease susceptibility, the available data remains scanty and inconclusive as they have not been validated in large, prospective cohorts. The present review aims to consolidate the available literature on the genetics of CAD in Asian Indians and seeks to provide insights on the concerns that need to be addressed in future studies to generate information having clinical value.

Perceptions of self-defined memory problems vary in south Asian minority older people who consult a GP and those who do not: a mixed-method pilot study

OBJECTIVE

South Asian older adults access services for mental health problems and dementia less than other older people in the UK, unlike for physical health problems. This pilot study investigated how South Asians with self-defined memory problems, with and without GP consultation, construe the symptoms, causes, consequences and treatment of the condition.

METHODS

Participants were recruited through community centres, their networks and memory clinics in Greater Manchester. The newly developed Barts Explanatory Model Inventory for Dementia (BEMI-D) was administered to 33 (18 M, 15 F) older South Asians aged 65 or above with memory problems in English, Gujarati or Urdu. Furthermore, cognition, executive function and depression were assessed.

RESULTS

Perceptions of dementia varied by GP consultation for memory problems. A greater proportion of older adults without a consultation considered memory problems to be given by God, saw acceptance of fate as an alternative treatment and did not identify medical support as appropriate. Forgetfulness and loss of social meaning were identified as symptoms of dementia more by those with a consultation. Higher levels of diabetes, heart disease and depression were found in those without a consultation.

CONCLUSIONS

Differences in perceptions may influence the decision about consulting a GP. Similarly, consultation for memory problems appears linked to extent physical health problems and mental health consultation (depression). These variations reported on a small scale in this pilot study suggest the need to explore the impact of perceptions on rates of GP consultation, so as to improve timely diagnosis and access to appropriate services.

Lipoprotein abnormalities in South Asians and its association with cardiovascular disease: Current state and future directions

South Asians have a high prevalence of coronary heart disease (CHD) and suffer from early-onset CHD compared to other ethnic groups. Conventional risk factors may not fully explain this increased CHD risk in this population. Indeed, South Asians have a unique lipid profile which may predispose them to premature CHD. Dyslipidemia in this patient population seems to be an important contributor to the high incidence of coronary atherosclerosis. The dyslipidemia in South Asians is characterized by elevated levels of triglycerides, low levels of high-density lipoprotein (HDL) cholesterol, elevated lipoprotein(a) levels, and a higher atherogenic particle burden despite comparable low-density lipoprotein cholesterol levels compared with other ethnic subgroups. HDL particles also appear to be smaller, dysfunctional, and proatherogenic in South Asians. Despite the rapid expansion of the current literature with better understanding of the specific lipid abnormalities in this patient population, studies with adequate sample sizes are needed to assess the significance and contribution of a given lipid parameter on overall cardiovascular risk in this population. Specific management goals and treatment thresholds do not exist for South Asians because of paucity of data. Current treatment recommendations are mostly extrapolated from Western guidelines. Lastly, large, prospective studies with outcomes data are needed to assess cardiovascular benefit associated with various lipid-lowering therapies (including combination therapy) in this patient population.

Panethnic Differences in Blood Pressure in Europe: A Systematic Review and Meta-Analysis

BACKGROUND

People of Sub Saharan Africa (SSA) and South Asians(SA) ethnic minorities living in Europe have higher risk of stroke than native Europeans(EU). Study objective is to provide an assessment of gender specific absolute differences in office systolic(SBP) and diastolic(DBP) blood pressure(BP) levels between SSA, SA, and EU.

METHODS AND FINDINGS

We performed a systematic review and meta-analysis of observational studies conducted in Europe that examined BP in non-selected adult SSA, SA and EU subjects. Medline, PubMed, Embase, Web of Science, and Scopus were searched from their inception through January 31st 2015, for relevant articles. Outcome measures were mean SBP and DBP differences between minorities and EU, using a random effects model and tested for heterogeneity. Twenty-one studies involving 9,070 SSA, 18,421 SA, and 130,380 EU were included. Compared with EU, SSA had higher values of both SBP (3.38 mmHg, 95% CI 1.28 to 5.48 mmHg; and 6.00 mmHg, 95% CI 2.22 to 9.78 in men and women respectively) and DBP (3.29 mmHg, 95% CI 1.80 to 4.78; 5.35 mmHg, 95% CI 3.04 to 7.66). SA had lower SBP than EU(-4.57 mmHg, 95% CI -6.20 to -2.93; -2.97 mmHg, 95% CI -5.45 to -0.49) but similar DBP values. Meta-analysis by subgroup showed that SA originating from countries where Islam is the main religion had lower SBP and DBP values than EU. In multivariate meta-regression analyses, SBP difference between minorities and EU populations, was influenced by panethnicity and diabetes prevalence.

CONCLUSIONS

1) The higher BP in SSA is maintained over decades, suggesting limited efficacy of prevention strategies in such group in Europe;2) The lower BP in Muslim populations suggests that yet untapped lifestyle and behavioral habits may reveal advantages towards the development of hypertension;3) The additive effect of diabetes, emphasizes the need of new strategies for the control of hypertension in groups at high prevalence of diabetes.

The Relationship of Metabolic Syndrome Traits with Beta-Cell Function and Insulin Sensitivity by Oral Minimal Model Assessment in South Asian and European Families Residing in the Netherlands

Background. There are different metabolic syndrome traits among patients with different ethnicities. Methods. We investigated this by studying 44 South Asians and 54 Europeans and classified them in three groups according to the occurrence of metabolic syndrome (MetS) and Type 2 Diabetes (T2D). Insulin sensitivity index (ISI), static, dynamic, and total beta-cell responsivity indices (Φ), and disposition indices (DIs) were calculated with the use of oral minimal model (OMM). Results. In both ethnicities, ISI was lower in the subgroup with MetS and T2D as compared to the subgroup without MetS nor T2D (P < 0.004). South Asians without MetS were more insulin resistant than Europeans without MetS (P = 0.033). In the South Asians, ISI, dynamic DI, and static DI were associated significantly (P < 0.006) with high-density lipoprotein cholesterol and triglycerides. In the Europeans, ISI was associated with waist-to-hip ratio (P = 0.005) and systolic and diastolic blood pressure (P < 0.005), while static DI was related to the systolic blood pressure (P = 0.005). Conclusions. MetS was linked with insulin resistance and reduced capacity to handle glucose regardless of ethnicity. ISI and DIs were associated with lipid traits in South Asians and with blood pressure in Europeans suggesting that insulin resistance enhances different metabolic syndrome traits among different ethnicities.

Meeting the Challenge of Diabetes in Ageing and Diverse Populations: A Review of the Literature from the UK

The impact of type 2 diabetes on ageing societies is great and populations across the globe are becoming more diverse. Complications of diabetes unequally affect particular groups in the UK older people, and people with a South Asian background are two population groups with increased risk whose numbers will grow in the future. We explored the evidence about diabetes care for older people with South Asian ethnicity to understand the contexts and mechanisms behind interventions to reduce inequalities. We used a realist approach to review the literature, mapped the main areas where relevant evidence exists, and explored the concepts and mechanisms which underpinned interventions. From this we constructed a theoretical framework for a programme of research and put forward suggestions for what our analysis might mean to providers, researchers, and policy makers. Broad themes of cultural competency; comorbidities and stratification; and access emerged as mid-level mechanisms which have individualised, culturally intelligent, and ethical care at their heart and through which inequalities can be addressed. These provide a theoretical framework for future research to advance knowledge about concordance; culturally meaningful measures of depression and cognitive impairment; and care planning in different contexts which support effective diabetes care for aging and diverse populations.

The objective measurement of physical activity and sedentary behaviour in 2-3 year olds and their parents: a cross-sectional feasibility study in the bi-ethnic Born in Bradford cohort

Background

The reported lower physical activity (PA) levels of British South Asians (SA) are suggested as a key influence in their increased risk of non-communicable diseases compared to their White British peers. Differences in objectively measured PA and sedentary behaviour (SB) between these ethnic groups have been observed during childhood (ages: 8–10 years). However, no information exists on objectively measured PA/SB in younger children, or how early in life differences in these behaviours emerge. Assessing PA/SB in the Born in Bradford (BIB) cohort study provides an opportunity to address such gaps in the literature, but previous studies have found recruiting and retaining SA participants challenging, and the feasibility of using accelerometers with SA children and parents is unknown.

This study investigated the feasibility of recruiting and objectively measuring the habitual PA/SB of 2–3 year old SA and White British children and parents from the BIB study.

Methods

Families were informed about the study during routine BIB assessments. Consenting families were visited at home for anthropometry measurements, interviews, material delivery and collection. Participants (child and parents) were instructed to wear the ActiGraph GT3X+ for 8 days. Descriptive statistics were computed, and ethnic differences tested (Chi-square) for recruitment uptake and compliance.

Results

160 families (30 % SA) provided contact details, and 97 (22 % SA) agreed to enter the study. White British families showed lower refusal and higher intake into the study than SA (p = 0.006). Of 89 children issued with an accelerometer, 34 % complied with the 8-day protocol (significantly less SA; p = 0.015) and 75 % provided enough days (≥3) to assess habitual PA/SB (no ethnic differences). Parental rates of compliance with the protocol did not differ between ethnicities. Issues experienced with the protocol and accelerometer use, and successful implementation strategies/procedures are presented.

Conclusions

Although greater efforts may be required to recruit SA, those consenting to participate were as likely as White British to provide enough data to assess habitual PA/SB. The issues and successful strategies reported in this feasibility study represent valuable information for planning future studies, and enhance recruitment and compliance with accelerometer protocols in SA and White British toddlers and parents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2481-z) contains supplementary material, which is available to authorized users.

Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation

We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10(-11) to 5.0 × 10(-21)). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10(-6)). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.

Barriers and Facilitators for Type-2 Diabetes Management in South Asians: A Systematic Review

Objective

Although South Asian populations have among the highest burden of type 2 diabetes in the world, their diabetes management remains poor. We systematically reviewed studies on South Asian patient’s perspectives on the barriers and facilitators to diabetes management.

Methods

We conducted a literature search using OVID, CINHAL and EMBASE (January, 1990 –February, 2014) evaluating the core components of diabetes management: interactions with health care providers, diet, exercise, and medication adherence. South Asian patients were self-reported as Indian, Pakistani, Malaysian-Indian or Bangladeshi origin. From 208 abstracts reviewed, 20 studies were included (19 qualitative including mixed methods studies, 1 questionnaire). Barriers and facilitators were extracted and combined using qualitative synthesis.

Results

All studies included barriers and few facilitators were identified. Language and communication discordance with the healthcare provider was a significant barrier to receiving and understanding diabetes education. There was inconsistent willingness to partake in self-management with preference for following their physician’s guidance. Barriers to adopting a diabetic diet were lack of specific details on South Asian tailored diabetic diet; social responsibilities to continue with a traditional diet, and misconceptions on the components of the diabetic diet. For exercise, South Asian patients were concerned with lack of gender specific exercise facilities and fear of injury or worsening health with exercise. Patients reported a lack of understanding about diabetes medication management, preference for folk and phytotherapy, and concerns about the long-term safety of diabetes medications. Facilitators included trust in care providers, use of culturally appropriate exercise and dietary advice and increasing family involvement. Overall themes for the barriers included lack of knowledge and misperceptions as well as lack of cultural adaptation to diabetes management.

Conclusion

Diabetes programs that focus on improving communication, addressing prevailing misconceptions, and culture specific strategies may be useful for improving diabetes management for South Asians.

Dietary quality and patterns and non-communicable disease risk of an Indian community in KwaZulu-Natal, South Africa

BACKGROUND

Limited data exist on the South African Indian diet despite their high prevalence of non-communicable diseases. This study attempted to determine the dietary quality and patterns of an Indian population in KwaZulu-Natal with reference to the high prevalence of non-communicable disease

METHODS

Two-hundred-and-fifty apparently healthy Indians, aged 35-55 years participated in a cross-sectional study where diet was assessed using a validated quantitative food frequency questionnaire. Mean intakes were compared to the World Health Organization goals. Dietary quality was determined by index construction and dietary patterns by factor analysis.

RESULTS

The mean daily percentage of energy (%E) from n-3 fatty acids (0.24 %E), dietary fibre (18.4 g/day) and fruit and vegetable intakes (229.4 g/day) were below the World Health Organization goals. Total fat (36.1 %E), polyunsaturated fatty acids (11.8 %E), n-6 fatty acids (11 %E) and free sugars (12.5 %E) exceeded the goals. The means for the deficient index reflected a moderate diet quality whereas, the excess index reflected good diet quality. The Pearson partial correlation coefficients between the deficient index and risk markers were weak whilst, the excess index was inversely correlated with waist circumference for the whole sample. Two factors were identified, based on the percentage of fat that contributed to each food group: factor 1 (meat and fish versus legume and cereal pattern), which accounted for added fat through food preparation; and Factor 2 (nuts and seeds versus sugars and visible fat pattern), which accounted for obvious fat. The medians for waist circumference, blood glucose, cholesterol and triglyceride levels showed significant decreasing trends for factor 1 (p < 0.05). The medians for blood glucose and cholesterol showed significant decreasing trends for factor 2 (p < 0.01).

CONCLUSION

A shortfall of fruit and vegetable, fibre and n-3 fatty acid intake in the diet is highlighted. When assessing the diet quality and patterns, guidance on the prudent use of added fats may lead to a healthier lifestyle reducing the prevalence of non-communicable diseases.

Pro-protein convertase subtilisin/kexin 9 concentrations correlate with coronary artery disease atheroma burden in a Pakistani cohort with chronic chest pain

OBJECTIVE

To determine the relationship between proprotein convertase subtilisin kexin 9 (PCSK9) levels and atheroma burden in Pakistanis presenting to an ambulatory centre with chest pain.

METHODS

A prospective matched case-control study of 400 patients selected for presence/absence of angiographic disease referred between 2001 and 2003. A comprehensive cardiovascular disease risk factor profile was assessed including demographics, environmental and biochemical risk factors including insulin resistance and PCSK-9 levels. Coronary atheroma burden was quantified by Gensini score.

RESULTS

In this population, PCSK-9 levels were weakly correlated (r = 0.23) with male gender (p = 0.06) and number of diabetes years (p = 0.09), and inversely with log10 of lipoprotein (a) concentration (p = 0.07) but not LDL-C. In multiple regression analysis, Gensini score was associated with age (p = 0.002), established angina (p = 0.001), duration of diabetes (p = 0.05), low HDL-C (p < 0.001), lipoprotein (a) (p = 0.01), creatinine (p < 0.001), C-Reactive Protein (p = 0.02) and PSCK-9 (p = 0.05) concentrations. PCSK9 added to the regression model. Neither total cholesterol nor LDL-C were significant risk factors in this study.

CONCLUSIONS

Proprotein convertase subtilisin kexin 9 concentrations are correlated with atheroma burden in Indian Asian populations from the sub-continent, not taking statin therapy, independent of LDL-C or other CVD risk factors.

Impact of ethnicity on progress of glycaemic control in 131,935 newly diagnosed patients with type 2 diabetes: a nationwide observational study from the Swedish National Diabetes Register

OBJECTIVES

Studies on ethnic disparities in glycaemic control have been contradictory, and compromised by excessively broad categories of ethnicity and inadequate adjustment for socioeconomic differences. We aimed to study the effect of ethnicity on glycaemic control in a large cohort of patients with type 2 diabetes.

SETTING

We used nationwide data (mainly from primary care) from the Swedish National Diabetes Register (2002-2011) to identify patients with newly diagnosed (within 12 months) type 2 diabetes.

PARTICIPANTS

We included 131,935 patients (with 713,495 appointments), representing 10 ethnic groups, who were followed up to 10 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Progress of glycated haemoglobin (HbA1c) for up to 10 years was examined. Mixed models were used to correlate ethnicity with HbA1c (mmol/mol). The effect of glycaemic disparities was examined by assessing the risk of developing albuminuria. The impact of ethnicity was compared to that of income, education and physical activity.

RESULTS

Immigrants, particularly those of non-Western origin, received glucose-lowering therapy earlier, had 30% more appointments but displayed poorer glycaemic control (2-5 mmol/mol higher HbA1c than native Swedes). Probability of therapy failure was 28-111% higher for non-Western groups than for native Swedes. High-income Western groups remained below the target-level of HbA1c for 4-5 years, whereas non-Western populations never reached the target level. These disparities translated into 51-92% higher risk of developing albuminuria. The impact of ethnicity was greater than the effect of income and education, and equal to the effect of physical activity.

CONCLUSIONS

Despite earlier pharmacological treatment and more frequent appointments, immigrants of non-Western origin display poorer glycaemic control and this is mirrored in a higher risk of developing albuminuria.

High prevalence of cardiovascular disease in South Asians: Central role for brown adipose tissue?

Cardiovascular disease (CVD) is the leading cause of death in modern society. Interestingly, the risk of developing CVD varies between different ethnic groups. A particularly high risk is faced by South Asians, representing over one-fifth of the world's population. Here, we review potential factors contributing to the increased cardiovascular risk in the South Asian population and discuss novel therapeutic strategies based on recent insights. In South Asians, classical ('metabolic') risk factors associated with CVD are highly prevalent and include central obesity, insulin resistance, type 2 diabetes, and dyslipidemia. A contributing factor that may underlie the development of this disadvantageous metabolic phenotype is the presence of a lower amount of brown adipose tissue (BAT) in South Asian subjects, resulting in lower energy expenditure and lower lipid oxidation and glucose uptake. As it has been established that the increased prevalence of classical risk factors in South Asians cannot fully explain their increased risk for CVD, other non-classical risk factors must underlie this residual risk. In South Asians, the prevalence of "inflammatory" risk factors including visceral adipose tissue inflammation, endothelial dysfunction, and HDL dysfunction are higher compared with Caucasians. We conclude that a potential novel therapy to lower CVD risk in the South Asian population is to enhance BAT volume or its activity in order to diminish classical risk factors. Furthermore, anti-inflammatory therapy may lower non-classical risk factors in this population and the combination of both strategies may be especially effective.

Is enhanced platelet activation the missing link leading to increased cardiovascular risk in psoriasis?

BACKGROUND

Psoriasis is an immune mediated inflammatory skin disease associated with systemic inflammation resulting in increased risk for associated cardiovascular co-morbidities. The role of platelet activation in the pathophysiology of this condition has not been clearly studied. We undertook to study the platelet activation markers in psoriasis, as compared to controls and to identify its association with disease severity in psoriasis.

METHODS

Sixty-two patients with psoriasis and 62 age and gender matched healthy controls were enrolled in this cross-sectional study. The severity of the disease was assessed using the psoriasis area severity index (PASI) scoring. The platelet indices [mean platelet volume (MPV) and platelet distribution width (PDW)] were estimated by an automated haematological laser optical analyzer. Plasma soluble P-selectin and platelet derived microparticle (PDMP) concentrations, serum high sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6 concentrations were estimated in all study participants. Platelet aggregation was assessed using adenosine diphosphate (ADP) as aggregating agent.

RESULTS

We observed that there was significantly higher platelet indices (MPV and PDW) in patients with psoriasis, when compared to controls. Plasma soluble P-selectin concentrations, PDMP and platelet aggregation were significantly elevated in patients with psoriasis, as compared to controls. We also found significantly higher concentrations of hs-CRP and IL-6 in patients with psoriasis, as compared to controls. Platelet activation and systemic inflammation markers correlated positively with PASI, except PDW. We also observed significant positive correlation between platelet activation and systemic inflammation in psoriasis.

CONCLUSION

Significant platelet activation and systemic inflammation were observed in patients with psoriasis, especially when associated with severe disease. The increased platelet activation might be the missing link between the persistent inflammation and the development of atherosclerotic plaque leading onto cardiovascular co-morbidities seen associated with psoriasis.

Cardiovascular health in migrants: current status and issues for prevention. A collaborative multidisciplinary task force report

OBJECTIVES

To review information on cardiovascular health and migration, to stress the attention of researchers that much needs to be done in the collection of sound data in Italy and to allow policy makers identifying this issue as an important public health concern.

BACKGROUND

In Italy, the rate of immigrants in the total number of residents increased from 2.5% in 1990 to 7.4% in 2010, and currently exceeds 10% in regions such as Lombardia, Emilia Romagna and Toscana.

METHODS

A consensus statement was developed by approaching relevant Italian national scientific societies involved in cardiovascular prevention. Task force members were identified by the president and/or the boards of each relevant scientific society or working group, as appropriate. To obtain a widespread consensus, drafts were merged and distributed to the scientific societies for local evaluation and revision by as many experts as possible. The ensuing final draft was finally approved by scientific societies.

RESULTS

In several western European countries, the prevalence of hypertension, diabetes, chronic kidney disease, obesity and metabolic syndrome was found to be higher among immigrants than in the native population. Although migrants are often initially healthier than non-migrant populations in their host countries, genetic factors, and changing environments with lifestyle changes, social exclusion and insufficient medical control may expose them to health challenges. Cultural reasons may also hamper both the dissemination of prevention strategies and migrant communication with healthcare providers. However, great diversity exists across and within different groups of migrants, making generalizations very difficult and many countries do not collect registry or survey data for migrant's health.

CONCLUSIONS

In the present economic context, the European Union is placing great attention to improve data collection for migrant health and to support the implementation of specific prevention policies aimed at limiting the future burden of cardiovascular and renal disease, and the consequent load for health systems. Wider initiatives on the topic are awaited in Italy.

An investigation of two-dimensional ultrasound carotid plaque presence and intima media thickness in middle-aged South Asian and European men living in the United kingdom

Objectives

Ultrasound studies of carotid intima media thickness (cIMT) and plaques are limited in South Asians, a group at elevated cardiovascular disease (CVD) risk. We determined whether South Asians have a difference in these ultrasound markers compared to Europeans living in the United Kingdom and whether measured risk factor(s) could account for any such differences.

Methods

One hundred South Asian men, aged 40 to 70 years and 100 European men of similar age and BMI, without diagnosed CVD or diabetes, underwent carotid ultrasound for measurement of cIMT and carotid plaque presence. Physical activity, cardiorespiratory fitness, anthropometry and blood pressure were assessed, fasted blood taken for measurement of cardiometabolic risk factors and demographic and lifestyle factors recorded.

Results

Age-adjusted mean (SD) cIMT was similar in South Asians and Europeans (0.64 (0.16) mm v 0.65 (0.12) mm, p = 0.64). Plaque was present in 48 South Asians and 37 Europeans and overall, there was no age-adjusted difference between South Asian and Europeans for plaque score(odds ratio 1.49, 95% CI, 0.86-2.80, p = 0.16), however, South Asians appeared to have more plaques at a younger age than Europeans; at age 40-50 years the odds of South Asians having plaques was 2.63 (95% CI, 1.16-5.93) times that for Europeans.

Conclusions

cIMT is similar between healthy South Asian and European men. Whilst there was no overall difference in plaque presence in South Asians, there is an indication of greater plaque prevalence at younger ages - an observation requiring further investigation. Prospective studies linking plaques to CVD outcomes in South Asians are needed to investigate whether these measures help improve CVD risk prediction.

Cardiovascular flexibility in middle-aged overweight South Asians vs. white Caucasians: response to short-term caloric restriction

BACKGROUND AND AIMS

South Asians have a higher risk of developing cardiovascular disease than white Caucasians. The underlying cause is unknown, but might be related to higher cardiac susceptibility to metabolic disorders. Short-term caloric restriction (CR) can be used as a metabolic stress test to study cardiac flexibility. We assessed whether metabolic and functional cardiovascular flexibility to CR differs between South Asians and white Caucasians.

METHODS AND RESULTS

Cardiovascular function and myocardial triglycerides were assessed using a 1.5T-MRI/S-scanner in 12 middle-aged overweight male South Asians and 12 matched white Caucasians before and after an 8-day very low calorie diet (VLCD). At baseline South Asians were more insulin resistant than Caucasians. Cardiac dimensions were smaller, despite correction for body surface area, and pulse wave velocity (PWV) in the distal aorta was higher in South Asians. Systolic and diastolic function, myocardial triglycerides and pericardial fat did not differ significantly between groups. After the VLCD body weight reduced on average by 4.0 ± 0.2 kg. Myocardial triglycerides increased in both ethnicities by 69 ± 18%, and diastolic function decreased although this was not significant in South Asians. However, pericardial fat and PWV in the proximal and total aorta were reduced in Caucasians only.

CONCLUSION

Myocardial triglyceride stores in middle-aged overweight and insulin resistant South Asians are as flexible and amenable to therapeutic intervention by CR as age-, sex- and BMI-matched but less insulin resistant white Caucasians. However, paracardial fat volume and PWV showed a differential effect in response to an 8-day VLCD in favor of Caucasians.

CLINICAL TRIAL REGISTRATION

NTR 2473 (URL: http://www.trialregister.nl/trialreg/admin/rctsearch.asp?Term=2473).

Ethnicity and risk of cardiovascular disease (CVD): 4.8 year follow-up of patients with type 2 diabetes living in Scotland

AIMS/HYPOTHESIS

Potential differences in cardiovascular risk by ethnicity remain uncertain. We evaluated the association of ethnicity with cardiovascular disease (CVD) incidence in a large cohort of people with type 2 diabetes living in Scotland.

METHODS

Data from Scottish Care Information-Diabetes (SCI-Diabetes) were linked to Scottish Morbidity Records (SMR01) and National Records of Scotland data for mortality for dates between 2005 and 2011. Of 156,991 people with type 2 diabetes with coded ethnicity, 121,535 (77.4%) had no CVD at baseline (White: 114,461; Multiple Ethnic: 2,554; Indian: 797; Other Asian: 319; Pakistani: 2,250; Chinese: 387; African-Caribbean: 301 and Other: 466) and were followed up (mean ± SD: 4.8 ± 2.3 years) for the development of fatal and non-fatal CVD.

RESULTS

During follow-up, 16,265 (13.4%) patients developed CVD (ischaemic heart or cerebrovascular diseases). At baseline, Pakistanis were younger and had developed diabetes earlier, had higher HbA1c and longer duration of diabetes, but had lower BP, BMI, creatinine, proportion of smokers and proportion on antihypertensive therapy than whites. The age and sex adjusted HRs for CVD were HR 1.31 (CI 1.17, 1.47), p < 0.001 in Pakistanis and HR 0.66 (CI 0.47, 0.92), p = 0.014 in Chinese compared with whites. Adjusting additionally for an area measure of deprivation, duration of diabetes, conventional CVD and other risk factors, the HR for Pakistanis (HR 1.45 [CI 1.14, 1.85], p = 0.002) was significantly higher, and that for Chinese (HR = 0.58 [CI 0.24, 1.40], p = 0.228) lower, compared with whites.

CONCLUSIONS/INTERPRETATION

Compared with whites with type 2 diabetes, those of Pakistani ethnicity in Scotland were at increased risk of CVD, whereas Chinese were at lower risk, with these differences unexplained by known risk factors.

Biomarkers of Coronary Artery Disease Differ Between Asians and Caucasians in the General Population

Coronary artery disease (CAD) markers have not been thoroughly investigated among Asians. The incidence of CAD, however, is rising rapidly in Asia. In this review, we systematically discuss publications that compare CAD biomarkers between Asians and Caucasians in the general population. A PubMed search yielded 5,570 hits, containing 59 articles describing 47 unique cohorts that directly compare Asians with Caucasians. Ten biomarkers were taken into account for this review: total cholesterol; triglycerides; high-density lipoprotein cholesterol; low-density lipoprotein cholesterol; C-reactive protein; glucose; insulin; glycated hemoglobin; fibrinogen; and plasminogen activator inhibitor-1. Triglycerides were 1.13-fold higher in South Asians than in Caucasians, and insulin levels were 1.33-fold higher. In Japanese and Chinese subjects, lower C-reactive protein levels were reported: 0.52 and 0.36-fold, respectively. Ethnicity-specific prognostic measures of CAD biomarkers were rarely reported. CAD biomarker levels differ between Asians and Caucasians and among Asian ethnic groups in population-based cohorts. The ethnicity-specific prognostic value of CAD biomarkers is yet to be determined.

The impact of health behaviours on incident cardiovascular disease in Europeans and South Asians--a prospective analysis in the UK SABRE study

Background

There is consistent evidence on the impact of health behaviours on risk of cardiovascular disease (CVD) in European populations. As South Asians in the UK have an excess risk of CVD and coronary heart disease (CHD) compared to Europeans, we investigated whether a similar association between combined health behaviours and risk of CVD and CHD among this high-risk group exists, and estimated the population impact.

Methods and Findings

In a prospective cohort of 1090 Europeans and 1006 South Asians (40–69 y) without prevalent CVD at baseline (1988–1990), followed up for 21 years to 2011, there were 601 incident CVD events [Europeans n = 255; South Asians n = 346] of which 520 were CHD events [n = 207 and 313 respectively]. Participants scored between 0 to 4 points for a composite score including four baseline healthy behaviours (non-smoker, moderate alcohol intake, physically active, frequent fruit/vegetable intake). Adjusted hazard ratios (95% confidence intervals) for incident CHD in Europeans who had three, two, one, and zero compared to four health behaviours were 1.33 (0.78–2.29), 1.96 (1.15–3.33), 1.36 (0.74–2.48) and 2.45 (1.18–5.10), respectively, p-trend = 0.025. In South Asians, corresponding HRs were 2.88 (1.33–6.24), 2.28 (1.06–4.91), 3.36 (1.53–7.39) and 3.48 (1.38–8.81), p-trend = 0.022. The results were similar for incident CVD; Europeans HR 2.12 (1.14–3.94), p–trend = 0.014; South Asians HR 2.73 (1.20–6.21), p-trend = 0.018. The population attributable fraction in Europeans was 43% for CHD and 28% for CVD. In South Asians it was 63% and 51% respectively.

Conclusions

Lack of adherence to four combined health behaviours was associated with 2 to 3-fold increased risk of incident CVD in Europeans and South Asians. A substantial population impact in the South Asian group indicates important potential for disease prevention in this high-risk group by adherence to healthy behaviours.

Diabetes and associated complications in the South Asian population

The rising prevalence of diabetes in South Asians has significant health and economic implications. South Asians are predisposed to the development of diabetes due to biologic causes which are exacerbated by lifestyle and environmental factors. Furthermore, they experience significant morbidity and mortality from complications of diabetes, most notably coronary artery disease, cerebrovascular disease, and chronic kidney disease. Therefore, understanding the pathophysiology and genetics of diabetes risk factors and its associated complications in South Asians is paramount to curbing the diabetes epidemic. With this understanding, the appropriate screening, preventative and therapeutic strategies can be implemented and further developed. In this review, we discuss in detail the biologic and lifestyle factors that predispose South Asians to diabetes and review the epidemiology and pathophysiology of microvascular and macrovascular complications of diabetes in South Asians. We also review the ongoing and completed diabetes prevention and management studies in South Asians.

Prescribing patterns and adherence to medication among South-Asian, Chinese and white people with type 2 diabetes mellitus: a population-based cohort study

AIM

To determine the prescribing of and adherence to oral hypoglycaemic agents, insulin, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and statin therapy among South-Asian, Chinese and white people with newly diagnosed diabetes.

METHODS

The present study was a population-based cohort study using administrative and pharmacy databases to include all South-Asian, Chinese and white people aged ≥ 35 years with diabetes living in British Columbia, Canada (1997-2006). Adherence to each class of medication was measured using proportion of days covered over 1 year with optimum adherence defined as ≥ 80%.

RESULTS

The study population included 9529 South-Asian, 14 084 Chinese and 143 630 white people with diabetes. The proportion of people who were prescribed angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statin or oral hypoglycaemic agents was ≤ 50% for all groups. South-Asian and Chinese people had significantly lower adherence for all medications than white people, with the lowest adherence to angiotensin-converting enzyme inhibitor treatment (South-Asian people: adjusted odds ratio 0.37, 95% CI 0.34-0.39; P<0.0001; Chinese people: adjusted odds ratio 0.50, 95% CI 0.47-0.54; P<0.0001) and statin therapy (South-Asian people: adjusted odds ratio 0.47, 95% CI 0.41 - 0.53, P < 0.0001; Chinese people: adjusted odds ratio 0.72, 95% CI 0.67 - 0.77; P<0.0001) compared with white people.

CONCLUSION

Adherence to evidence-based pharmacotherapy was substantially worse among the South-Asian and Chinese populations. Care providers need to be alerted to the high levels of non-adherence in these groups and the underlying causes need to be investigated.

Angiographic coronary artery disease and high-sensitivity troponin-T in a native Pakistani cohort presenting with chronic chest pain

OBJECTIVE

To determine the relationship between troponin-T levels and atheroma burden in Pakistanis presenting to an ambulatory centre with chest pain.

METHODS

A prospective case-control study of 400 patients selected for presence/absence of angiographic disease referred between 2001 and 2003. A comprehensive cardiovascular disease (CVD) risk factor profile was assessed including demographics, environmental and biochemical risk factors including insulin resistance and troponin-T levels. Coronary atheroma burden was quantified by Gensini score.

RESULTS

Clinically significant elevated troponin-T levels (> 30 pmol/l) were found in 40 patients (10%) with equal numbers in groups selected with or without angiographic disease. Troponin-T elevation (> 13 pmol/l) was present in 59 vs. 47 patients (30% vs. 24%; p = 0.04). Troponin-T levels did not correlate with any measured demographical, environmental, drug therapy or biochemical risk factor. No difference was found in concentrations of lipids, apolipoproteins, insulin resistance, C-reactive protein or sialic acid in cohorts stratified by troponin-T concentrations. In univariate analysis comparing patients with high (> 30 pmol/l) and low troponin-T levels (< 13 pmol/l) higher plasma total protein (91 g/l vs. 85 g/l; p = 0.01), increased immunoglobulin levels (41 g/l vs. 36 g/l; p = 0.02) and prevalence of hyperparathyroidism (40% vs. 21%; p = 0.04) were associated with higher troponin-T concentrations.

CONCLUSIONS

This study shows that measurement of troponin-T is not an alternative to imaging in an Indian asian population, but that it does identify a separate potentially high-risk population that would not be identified by the use of imaging alone which is potentially at higher risk of CVD events.

Associations of prediabetes with all-cause and cardiovascular mortality: a meta-analysis

BACKGROUND

Reports on the association of prediabetes with all-cause mortality and cardiovascular mortality are inconsistent. Objective. To evaluate the risk of all-cause and cardiovascular mortality in association with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT).

METHODS

Prospective cohort studies with data on prediabetes and mortality were included. The relative risks (RRs) of all-cause and cardiovascular mortality were calculated and reported with 95% confidence intervals (95% CIs).

RESULTS

Twenty-six studies were included. The risks of all-cause and cardiovascular mortality were increased in participants with prediabetes defined as IFG of 110-125 mg/dL (IFG 110) (RR 1.12, 95% CI 1.05-1.20; and RR 1.19, 95% CI 1.05-1.35, respectively), IGT (RR 1.33, 95% CI 1.24-1.42; RR 1.23, 95% CI 1.11-1.36, respectively), or combined IFG 110 and/or IGT (RR 1.21, 95% CI 1.11-1.32; RR 1.21, 95% CI 1.07-1.36, respectively), but not when IFG was defined as 100-125 mg/dL (RR 1.07, 95% CI 0.92-1.26; and RR 1.16, 95% CI 0.94-1.42, respectively).

CONCLUSIONS

Prediabetes, defined as IFG 110, IGT, or combined IFG 110 and/or IGT, was associated with increased all-cause and cardiovascular mortality.

Prediabetes and the risk of cancer: a meta-analysis

AIMS/HYPOTHESIS

The results from prospective cohort studies of prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and risk of cancer are controversial. We conducted a meta-analysis to evaluate the risk of cancer in association with impaired fasting glucose and impaired glucose tolerance.

METHODS

The PubMed, EMBASE and Cochrane Library databases were searched for prospective cohort studies with data on prediabetes and cancer. Two independent reviewers assessed the reports and extracted the data. Prospective studies were included if they reported adjusted RRs with 95% CIs for the association between cancer and prediabetes. Subgroup analyses were conducted according to endpoint, age, sex, ethnicity, duration of follow-up and study characteristics.

RESULTS

Data from 891,426 participants were derived from 16 prospective cohort studies. Prediabetes was associated with an increased risk of cancer overall (RR 1.15; 95% CI 1.06, 1.23). The results were consistent across cancer endpoint, age, duration of follow-up and ethnicity. There was no significant difference for the risk of cancer with different definitions of prediabetes. In a site-specific cancer analysis, prediabetes was significantly associated with increased risks of cancer of the stomach/colorectum, liver, pancreas, breast and endometrium (all p < 0.05), but not associated with cancer of the bronchus/lung, prostate, ovary, kidney or bladder. The risks of site-specific cancer were significantly different (p = 0.01) and were highest for liver, endometrial and stomach/colorectal cancer.

CONCLUSIONS/INTERPRETATION

Overall, prediabetes was associated with an increased risk of cancer, especially liver, endometrial and stomach/colorectal cancer.

Carotid intima media thickness and low high-density lipoprotein (HDL) in South Asian immigrants: could dysfunctional HDL be the missing link?

INTRODUCTION

South Asian immigrants (SAIs) in the US exhibit higher prevalence of coronary artery disease (CAD) and its risk factors compared with other ethnic populations. Conventional CAD risk factors do not explain the excess CAD risk; therefore there is a need to identify other markers that can predict future risk of CAD in high-risk SAIs. The objective of the current study is to assess the presence of sub-clinical CAD using common carotid artery intima-media thickness (CCA-IMT), and its association with metabolic syndrome (MS) and pro-inflammatory/dysfunctional HDL (Dys-HDL).

MATERIAL AND METHODS

A community-based study was conducted on 130 first generation SAIs aged 35-65 years. Dys-HDL was determined using the HDL inflammatory index. Analysis was completed using logistic regression and Fisher's exact test.

RESULTS

Sub-clinical CAD using CCA-IMT ≥ 0.8 mm (as a surrogate marker) was seen in 31.46%. Age and gender adjusted CCA-IMT was significantly associated with type 2 diabetes (p = 0.008), hypertension (p = 0.012), high-sensitivity C-reactive protein (p < 0.001) and homocysteine (p = 0.051). Both the presence of MS and Dys-HDL was significantly correlated with CCA-IMT, even after age and gender adjustment. The odds of having Dys-HDL with CCA-IMT were 5 times (95% CI: 1.68, 10.78).

CONCLUSIONS

There is a need to explore and understand non-traditional CAD risk factors with a special focus on Dys-HDL, knowing that SAIs have low HDL levels. This information will not only help to stratify high-risk asymptomatic SAI groups, but will also be useful from a disease management point of view.

Attribution of risk for coronary heart disease in a vulnerable immigrant population: a survey study

BACKGROUND

Coronary heart disease (CHD) is a common and costly condition and is increasing at a higher rate among Asian Indians than among other ethnic groups. An understanding of how Asian Indians perceive their risk is important for health providers to develop culturally appropriate programs to raise awareness of the risk of CHD.

OBJECTIVE

The aim of this survey was to investigate the attribution of risk factors for CHD among the Asian Indian community in Australia.

METHODS

Asian Indian community leaders were recruited to provide their views of how their community perceived the risk of CHD. An online survey collected demographic data and information from the Illness Perception Questionnaire-Revised, which measures 6 domains of illness perception: timeline acute/chronic, consequences, emotional impact, personal control, treatment efficacy, and illness comprehension.

RESULTS

An 84% response rate (n = 49) was achieved from Asian Indian community leaders. Heart disease and cancer were considered to be the illnesses of major concern. Participants indicated that people in their community perceived hereditary factors (90%), hypertension, stress or worry (84%), and aging (86%) as the major cause of their illnesses. Smoking, high blood pressure, and cholesterol were identified as being major risk factors for CHD.

CONCLUSIONS

These data suggest that as well as strategies to address risk factors such as diet and exercise, stress management is an important issue to consider in developing community-based programs.

The South Asian genome

The genetic sequence variation of people from the Indian subcontinent who comprise one-quarter of the world's population, is not well described. We carried out whole genome sequencing of 168 South Asians, along with whole-exome sequencing of 147 South Asians to provide deeper characterisation of coding regions. We identify 12,962,155 autosomal sequence variants, including 2,946,861 new SNPs and 312,738 novel indels. This catalogue of SNPs and indels amongst South Asians provides the first comprehensive map of genetic variation in this major human population, and reveals evidence for selective pressures on genes involved in skin biology, metabolism, infection and immunity. Our results will accelerate the search for the genetic variants underlying susceptibility to disorders such as type-2 diabetes and cardiovascular disease which are highly prevalent amongst South Asians.

South Asian Ethnicity and Cardiovascular Risk

South Asians (SAs), in their countries or after migration, are at high risk of coronary artery disease (CAD) and mortality compared to other ethnic groups. It has been shown that >90% of CAD global risk could be attributed to 9 modifiable risk factors (RFs) worldwide. However, these conventional RFs may not fully explain this high risk of CAD among SAs. Therefore, attention has been directed toward nonconventional RFs. In this narrative review, we evaluate the conventional and emerging cardiovascular RFs characterizing SAs. These factors may explain the high morbidity and mortality among SAs. Further prospective studies are urgently needed to set algorithms for the optimal management of these RFs in high-risk populations like SAs.

Acute coronary syndrome and ethnicity: observations from the Middle East

AIMS

To evaluate the presentation and outcome of South Asian (SAP) to Middle Eastern Arabs (MEAP) patients presenting with acute coronary syndrome.

METHODS

Data were collected retrospectively in Qatar between 1991 and 2010, and were analyzed according to patient ethnicity.

RESULTS

Of 14,593 acute coronary syndrome patients, 49% were MEAP and 51% were SAP. When compared with MEAP, SAP were younger, males and smokers (p < 0.01). Other cardiovascular risk factors were less common in SAP when compared with MEAP. ST-elevation myocardial infarction and the use of evidence-based medications were more prevalent among SAP (all p < 0.001). Compared to MEAP, SAP had better in-hospital outcomes; however, ethnicity was not an independent predictor of in-hospital mortality.

CONCLUSION

In contrary to data from Western countries, SAP living in the Middle East are younger with lower cardiovascular risk profile and better outcomes when compared with Arab patients. However, further studies are warranted.

Haemostatic factors, lipoproteins and long-term mortality in a multi-ethnic population of Gujarati, African-Caribbean and European origin

OBJECTIVES

To examine the relations between haemostatic factors and lipoproteins with mortality in British Europeans, African-Caribbeans (AfC) and Gujarati Indians.

METHODS

A prospective cohort study of 331 subjects (40-79 years), followed-up over 26 years for mortality. Apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B), factor VII coagulant activity (FVIIc), fibrinogen and von Willebrand Factor (vWF) were measured at baseline in 118 Europeans, 100 AfC and 113 Gujaratis. Aortic pulse wave velocity (aPWV) was measured in 174 participants.

RESULTS

147 (44.4%) subjects died during a median of 24 years follow-up with 69 cardiovascular deaths. Women at baseline had higher, and AfC males the lowest FVIIc and Apo-A1 levels. Baseline age-sex and ethnicity adjusted FVIIc levels were higher in those who died (131.0 vs. 117.4%; P = 0.048). In similarly adjusted partial correlations, Apo-A1 was inversely related to arterial stiffness (ρ = -0.23, P = 0.04). Over the 26 years follow-up, participants below the median (i.e. with lower concentration) of FVIIc, Fibrinogen, Apo-B and vWF had better survival rates than those with higher concentrations; those with higher concentrations of Apo-A1 had better survival. In Cox multivariable regression analyses including sex, ethnicity and aPWV, independently increased risk of all-cause mortality came only from SBP (per 5 mmHg); P = 0.011), age (per year); P < 0.0001 and FVIIc at 7% (per 10-unit; HR 1.07 (1.02, 1.12); P = 0.008. Separately, Apo-A1 (HR 0.12 (0.02, 0.75; P = 0.029) was independently associated with a very significant 88% reduction in all-cause mortality.

CONCLUSIONS

Despite a relatively small sample size, long-term follow-up suggests an independent effect of the prothrombotic state (via FVIIc) and apo-A1 (a constituent of HDL) on mortality.

Comparison by computed tomographic angiography-the presence and extent of coronary arterial atherosclerosis in South Asians versus Caucasians with diabetes mellitus

South Asians in the Western world have a high prevalence of diabetes mellitus (DM) and an increased risk of coronary artery disease (CAD) and mortality compared with Caucasians. CAD in asymptomatic South Asian patients with type 2 DM has not been investigated. The aim of this observational cohort study was to investigate CAD in asymptomatic South Asian patients with type 2 DM and to compare with matched Caucasian patients. A total of 120 asymptomatic South Asian patients with type 2 DM and matched Caucasian patients (mean age 52 years, 55% men) were derived from an ongoing registry of cardiovascular risk stratification in asymptomatic patients with DM. Cardiovascular risk assessment included multidetector row coronary computed tomography angiography. CAD was assessed as the coronary artery calcium score and classified into no signs of atherosclerosis or minor wall irregularities <30%, nonsignificant CAD 30% to 50%, or significant CAD ≥50% stenosis. On a patient base, CAD was scored according to the severity and number of vessels and segments with significant CAD. Subsequently, CAD was assessed per coronary artery and per segment. Compared with Caucasian patients, South Asian patients had a significantly higher coronary artery calcium score and higher prevalence of significant CAD (41% vs 28%, respectively, p = 0.008), involving more coronary vessels and segments. Significant CAD was especially more frequent in the left anterior descending coronary artery. In conclusion, asymptomatic South Asian patients with type 2 DM have a higher prevalence and extent of CAD compared with matched Caucasian patients.

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.