Greater adverse effects of cholesterol and diabetes on carotid intima–media thickness in South Asian Indians: Comparison of risk factor-IMT associations in two population-based surveys

doi:10.1016/j.atherosclerosis.2007.10.008

Atherosclerosis

Volume 199, Issue 1, July 2008, Pages 116-122

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Abstract

Asian Indians appear particularly susceptible to coronary heart disease compared with other ethnic groups. We compared the effects of vascular risk factors on carotid intima–media thickness (IMT) in a population of South Asians from Andhra Pradesh, India with a population of Caucasians from Perth, Australia.

Cardiovascular risk factors and ultrasound-assessed carotid IMT were measured in randomly selected adults from two villages in rural India (n = 303) and compared to those for randomly sampled adults from Australia (n = 1111). Regression models with interaction terms were used to compare the strengths of associations between risk factors and carotid IMT, in these two populations. There were stronger associations of cholesterol (p for interaction = 0.009) and diabetes (p = 0.04) with carotid IMT in the Indian compared to the Australian population. Also, while increasing HDL-cholesterol was associated with decreasing carotid IMT in the Australian population the reverse was true for the Indian population (p < 0.001). The associations with IMT of blood pressure, triglycerides, age, HDL to total cholesterol ratio, glucose, BMI, waist, waist to hip ratio and smoking were not different between the populations.

Greater adverse effects of total cholesterol and diabetes on atherosclerosis and no protective effect of HDL-cholesterol amongst Asian Indians provide a novel possible explanation for observed excess rates of cardiovascular disease amongst these populations.

Introduction

There are substantial data from the United Kingdom, Canada and Singapore showing that populations of South Asian Indian background have markedly higher mortality from coronary heart disease (CHD) than is seen in other population groups [1], [2], [3]. Although levels of known cardiovascular risk factors vary between these groups, they do not fully explain the differences in CHD rates [4]. One possible reason for this is that there might be ethnic differences in susceptibility to the atherogenic effects of certain vascular risk factors.

Carotid intima–media thickness (IMT) is a well-established indicator of atherosclerosis and has been shown to correlate with traditional cardiovascular risk factors, the presence of coronary and carotid atherosclerosis and the risk of future myocardial infarction or stroke [5], [6]. Carotid IMT has also been used to quantify atherosclerotic disease burden in different ethnic groups [7], [8] but previous analyses have largely restricted themselves to comparing mean levels of carotid IMT between populations. In this study, we sought to compare the associations of cardiovascular risk factors with carotid IMT between an Asian and a Caucasian population, to investigate possible differences in the susceptibility of these populations to established vascular risk factors.

Section snippets

Methods

This study involved the comparison of risk factor effects on carotid intima–media thickness in a Caucasian population from Perth, Australia in 1999 [9] versus an Asian Indian population from rural South India studied in 2004 [10]. The India-based component of the project was done as part of the Andhra Pradesh Rural Health Initiative (APRHI) and was approved by the Ethics Committees of the CARE Hospital, Hyderabad in India and the University of Sydney in Australia. The Ethics Committee of the

Participant characteristics

The average age of the Indian study participants was 51 (range 20–90) years and the Australian participants 53 (range 27–77) years. The proportion of males studied was 45% and 50%, respectively. The age- and sex-adjusted levels of cardiovascular risk factors were mostly different between populations with worse levels of blood pressure, total cholesterol, LDL-cholesterol, fasting plasma glucose, body mass index, waist and weight in the Australian compared to Indian group and smoking,

Discussion

The data presented here suggest that cholesterol and diabetes are associated with more adverse effects on carotid IMT in South Asian Indians than in Caucasian Australians and provide a possible contributing explanation to the observed greater susceptibility of South Asian Indians to cardiovascular disease [1], [2], [3]. Greater atherogenic effects of cholesterol and diabetes in South Asian Indians might also explain the higher mean levels of carotid IMT observed in this Indian population,

Conflict of interest

None.

Acknowledgements

APRHI (Andhra Pradesh Rural Health Initiative) has been developed as a collaboration between four partners, The Byrraju Foundation in Hyderabad, India, The Center for Chronic Disease Control (CCDC) in Delhi, India, The Care Foundation in Hyderabad, India and The George Institute for International Health in Sydney, Australia. We would like to acknowledge the support of Dr. Srinath Reddy, CCDC; Dr. David Sullivan, Department of Biochemistry, Royal Prince Alfred Hospital; Prof. Mark Woodward and

References (29)

S.S. Anand et al.
Differences in risk factors, atherosclerosis, and cardiovascular disease between ethnic groups in Canada: the Study of Health Assessment and Risk in Ethnic groups (SHARE)
Lancet
(2000)
C.K. Chow et al.
Cardiovascular disease and risk factors among 345 adults in rural India—the Andhra Pradesh Rural Health Initiative
Int J Cardiol
(2007)
G. Puavilai et al.
Diagnostic criteria for diabetes mellitus and other categories of glucose intolerance: 1997 criteria by the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus (ADA), 1998 WHO consultation criteria, and 1985 WHO criteria. World Health Organization
Diabetes Res Clin Pract
(1999)
B.M. McQuillan et al.
Antioxidant vitamins and the risk of carotid atherosclerosis. The Perth Carotid Ultrasound Disease Assessment study (CUDAS)
J Am Coll Cardiol
(2001)
K.S. Woo et al.
Chinese adults are less susceptible than whites to age-related endothelial dysfunction
J Am Coll Cardiol
(1997)
H.T. Pedoe et al.
Coronary heart-attacks in East London
Lancet
(1975)
J.T. Knuiman et al.
Role of diet to HDL-cholesterol and coronary disease: serum total and HDL-cholesterol in boys and men from developing and developed countries
Am Heart J
(1982)
C. Chow et al.
Significant lipid, adiposity and metabolic abnormalities amongst 4535 Indians from a developing region of rural Andhra Pradesh
Atherosclerosis
(2008)
R. Bhopal
What is the risk of coronary heart disease in South Asians? A review of UK research
J Public Health Med
(2000)
T. Sheth et al.
Cardiovascular and cancer mortality among Canadians of European, south Asian and Chinese origin from 1979 to 1993, an analysis of 1.2 million deaths
Can Med Assoc J
(1999)

K. Hughes et al.

Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. I. Differences in mortality

J Epidemiol Commun Health

(1990)

K. Hughes et al.

Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. II. Differences in risk factor levels

J Epidemiol Commun Health

(1990)

M.W. Lorenz et al.

Prediction of clinical cardiovascular events with carotid intima–media thickness: a systematic review and meta-analysis

Circulation

(2007)

L.E. Chambless et al.

Association of coronary heart disease incidence with carotid arterial wall thickness and major risk factors: the Atherosclerosis Risk in Communities (ARIC) Study, 1987–1993

Am J Epidemiol

(1997)

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La mesure de l'épaisseur intima-média (EIM), longtemps négligée, est un élément fondamental de la prédiction des événements cardiovasculaires. L'échographie Doppler vasculaire est l'un des outils nécessaires pour objectiver l'athérosclérose.
Le but de notre étude est d'établir une corrélation entre les événements cardiovasculaires et l'épaisseur intima-média.
Nous avons réalisé une étude prospective sur une période de 6 mois dans le service de cardiologie de notre centre hospitalier Ibn-Rochd, à partir des données de l'échographie Doppler vasculaire. Les patients ont été recrutés lors des vacations vasculaires, présentant un facteur de risque et ou une maladie cardiovasculaire vasculaire des troncs supra-aortiques à l'aide d'une sonde linéaire haute fréquence (7,5 MHZ) connectée à un appareil d'échographie GENERAL Electric. L'épaisseur intima-média était considérée comme normale < 0,8 mm chez les patients adultes âgés de 40 à 60 ans.
L'EIM ≥ 0,8 mm était retrouvée chez 89,2 % des patients sur un total de 102 patients recrutés, à prédominance masculine (54,9 %) avec un âge moyen à 56 ± 9 ans. Les facteurs de risque cardiovasculaire et les maladies cardiovasculaires étaient associés à une élévation de l'EIM. Les diabétiques étaient les plus fréquents à avoir une EIM élevée, retrouvés à 50,9 %, suivi de 43,1 % des hypertendus, de 27,4 % de façon respective entre les hémodialysés et les accidents cérébraux ischémiques puis 14 % chez les coronariens avec indication de pontage.
L'EIM élevée est associée aux événements cardiovasculaires et devrait être recherchée comme leur indicateur primaire dans les prochaines études de grande envergure afin que son évaluation soit systématique devant un facteur de risque cardiovasculaire.
The measurement of intima-media thickness (IMT), long neglected, is a fundamental element in the prediction of cardiovascular events. Vascular Doppler ultrasonography is one of the tools needed to objectify atherosclerosis.
The aim of our study is to establish a correlation between cardiovascular events and intima-media thickness.
We conducted a prospective, cross-sectional and descriptive study over a period of 6 months in the cardiology department of Chu-Ibn Rochd, based on vascular Doppler ultrasound data, presenting a risk factor and or vascular cardiovascular disease of the supra-aortic trunks using a high frequency linear probe (7.5 MHZ) connected to a GENERAL Electric ultrasound machine. Intima-media thickness was considered normal < 0.8 mm in adult patients aged 40–60 years.
IMT ≥ 0.8 mm was found in 89.2% of patients out of a total of 102 patients recruited, predominantly male (54.9%) with a mean age of 56 ± 9 years. Cardiovascular risk factors and cardiovascular diseases were associated with an increase in IMT. Diabetics were the most frequent to have an elevated IMT, found at 50.9%, followed by 43.1% of hypertensives, 27.4% respectively between haemodialysis patients and ischemic strokes and 14% in coronary patients with indication of bypass surgery.
Elevated IMT is associated with cardiovascular events and should be sought as their primary indicator in future large-scale studies so that it can be routinely assessed for a cardiovascular risk factor.
The Burden of Atherosclerotic Cardiovascular Disease in South Asians Residing in Canada: A Reflection From the South Asian Heart Alliance
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South Asians (SAs), originating from the Indian subcontinent (India, Pakistan, Sri Lanka, Bangladesh, Nepal, and Bhutan), represent one quarter of the global population and are the largest visible minority in Canada. SAs experience the highest rates of coronary artery disease in Canada. Although conventional cardiovascular risk factors remain predictive in SA, the excess risk is not fully explained by these risk factors alone. Abdominal obesity, metabolic syndrome, and insulin resistance likely contribute a greater risk in SAs than in other populations. The South Asian Heart Alliance has been recently formed to investigate and recommend the best strategies for the prevention of cardiometabolic disease in SAs in Canada. This topic review represents a comprehensive overview of the magnitude of cardiovascular disease in SAs in Canada, with a review of conventional and novel risk markers in the SA population. Both primary and secondary prevention strategies are suggested and when possible, adapted specifically for the SA population. The need for SAs and their healthcare professionals to be more aware of the problem and potential solutions, along with the need for population-specific research, is highlighted.
Les Asiatiques du sud originaires du sous-continent indien (Inde, Pakistan, Sri Lanka, Bangladesh, Népal et Bhoutan) représentent le quart de la population mondiale et constituent la plus importante minorité visible au Canada. C’est aussi au sein de cette population qu’on observe les taux de coronaropathie les plus élevés au Canada. Bien que les facteurs de risque cardiovasculaire classiques conservent leur valeur prédictive chez les Asiatiques du sud, ils n’expliquent pas à eux seuls le risque excédentaire observé. L’obésité abdominale, le syndrome métabolique et l’insulinorésistance constituent vraisemblablement des facteurs de risque plus importants chez les Asiatiques du sud que dans les autres populations. La South Asian Heart Alliance a récemment été mise sur pied afin d’explorer les stratégies exemplaires pour la prévention des maladies cardiométaboliques chez les Asiatiques du sud au Canada et de formuler des recommandations à cet égard. Cette revue thématique présente un aperçu de l’importance des maladies cardiovasculaires au sein de la population des Asiatiques du sud du Canada, ainsi qu’un résumé des marqueurs de risque classiques et nouveaux dans cette population. Les auteurs proposent des stratégies de prévention primaire et secondaire adaptées, dans la mesure du possible, à la population des Asiatiques du sud. Ils font également ressortir l’importance de sensibiliser davantage les Asiatiques du sud et les professionnels de la santé aux risques et aux solutions possibles, ainsi que la nécessité de mener des recherches axées sur cette population particulière.
A Study to derive distribution of carotid intima media thickness and to determine its COrrelation with cardiovascular Risk factors in asymptomatic nationwidE Indian population (SCORE-India)
2016, Indian Heart Journal
Citation Excerpt :
However, CIMT is significantly influenced by ethnicity and therefore ethnic-specific reference values are needed for interpreting CIMT values in a given individual. Although numerous small scale studies have evaluated associations of CIMT in Indian subjects,17–22 there is unfortunately no large-scale study to provide normal values of CIMT in Indian subjects. Therefore, this study was sought with the primary objective of defining normal distribution of CIMT in Indian subjects and to also explore the relationship of CIMT values with various demographics characteristics and CVD risk factors in Indians.
There is presently no data to describe normal distribution of carotid intima-media thickness (CIMT), an established measure of subclinical atherosclerosis, in Indian subjects.
In this multi-centric study, 1229 subjects with age ≥30 years and no previous cardiovascular disease (CVD) underwent CVD risk factor assessment and CIMT measurement. Mean far wall common carotid artery IMT was measured on both sides and averaged.
Mean age of the subjects was 48.0 ± 12.0 years and 54.2% were men. CIMT measurement was feasible in 1157 subjects. Mean, median and 75th percentile values of CIMT for different age-groups were derived for men and women separately. There was a progressive increase in CIMT with increasing age (P < 0.001) and men had higher CIMT values than women (0.608 ± 0.12 mm vs. 0.579 ± 0.11 mm, P < 0.001). The CIMT values were also higher in diabetics (0.635 ± 0.10 mm) and hypertensives (0.624 ± 0.10 mm) as compared to non-diabetics (0.589 ± 0.12 mm, P < 0.001) and non-hypertensives (0.592 ± 0.12, P 0.02) respectively. Among continuous variables, age, systolic blood pressure and fasting blood glucose had strong to modest correlation with CIMT (Pearson's r 0.524, 0.282 and 0.192 respectively, all P values <0.001), whereas body mass index, diastolic blood pressure and serum triglycerides exhibited weak but still statistically significant relationship (Pearson's r 0.069, P 0.019; Pearson's r 0.065, P 0.026; and Pearson's r 0.094, P 0.001, respectively).
This is the first study to provide age- and gender-specific distribution of CIMT in Indian subjects free from CVD. This information should help facilitate further research and clinical work involving CIMT in India.
Relationship between different cardiovascular risk scores and measures of subclinical atherosclerosis in an Indian population
2015, Indian Heart Journal
Relative accuracy of the various currently available cardiovascular (CV) risk assessment algorithms in Indian patients is not known.
This study included 194 consecutive patients (mean age 49.6 ± 10.3 years, 84.5% males) attending a CV disease prevention clinic at a tertiary center in north India. Four risk assessment models [Framingham Risk score (Risk_FRS), American College of Cardiology/American Heart Association pooled cohort equations (Risk_ACC/AHA), the 3rd iteration of Joint British Societies' risk calculator (Risk_JBS) and the World Health Organization/International Society of Hypertension risk prediction charts (Risk_WHO)] were applied. The estimated risk scores were correlated with carotid intima-media thickness (CIMT) and coronary calcium score (CCS) using nonparametric statistics (Chi-square test, Kruskal–Wallis test and Spearman rank correlation).
Overall, Risk_ACC/AHA and Risk_WHO significantly underestimated CV risk as compared to Risk_JBS and Risk_FRS, with Risk_JBS being the least likely to underestimate the risk (patients with coronary artery disease who were found to have ≥20% CV risk- 21.4% with Risk_ACC/AHA, 17.9% with Risk_WHO, 41.4% with Risk_FRS, and 58.6% with Risk_JBS). Further, only Risk_JBS and Risk_FRS, but not Risk_ACC/AHA and Risk_WHO, demonstrated consistent relationship with CIMT and CCS (Spearman rho 0.45 and 0.46 for Risk_JBS and 0.39 and 0.36 for Risk_FRS for CIMT and CCS respectively, all p values < 0.001).
The present study shows that in Indian subjects Risk_JBS appears to provide the most accurate estimation of CV risk. It least underestimates the risk and has the best correlation with CIMT and CCS. However, large-scale prospective studies are needed to confirm these findings.
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Ethnic differences in lower limb revascularisation and amputation rates. Implications for the aetiopathology of atherosclerosis?
2014, Atherosclerosis
Citation Excerpt :
Chaturvedi et al. showed that for a given level of coronary artery calcification, Asians had less femoral artery calcification than Whites [28]. Lower levels of PAD have also been used to explain fewer diabetes related amputations [29] Chow et al. showed that hypercholesterolaemia and diabetes were particularly associated with carotid atherosclerosis in Asians than Australian Whites with the protective effect of HDL not apparent in Asians [30]. This population is self defined as ‘Black African’, ‘Black Caribbean’, and ‘Black Other’.
Peripheral arterial disease, as a result of atherosclerosis, is the commonest reason for lower limb revascularisation and amputation in England. We describe the prevalence rate of these procedures among the White, South Asian and Black populations living in England and describe the association of ethnicity to amputation, both with and without, revascularisation.
We extracted data from 90 million English hospital admissions between 2003 and 2009 and calculated prevalence rates among 50–84 year olds using census data. Logistic regression demonstrated whether ethnicity was related to amputation, both with and without revascularisation, independent of demographic (age, sex, social class) and disease risk factors (diabetes, hypertension, hypercholesterolaemia, coronary and cerebral vascular disease, smoking).
There were 25 308 amputations and 136 215 revascularisations. The age adjusted prevalence rate for amputation was 26/100 000 and revascularisation 142/100 000. The prevalence ratio (95% confidence intervals) (White British = 100) of amputation in the Asian and Black populations was; 60 (54–66) and 169 (155–183) respectively with revascularisation ratios; 89 (86–92) and 94 (89–98) respectively. South Asians had approximately half the risk of amputation both with and without a revascularisation than Whites despite much higher rates of known atherosclerotic risk factors. The odds of having an amputation without any revascularisation was 63% higher in Blacks but fully attenuated by demographic and disease risk factors.
South Asians experience the lowest rate of both major lower limb amputation and revascularisation in England. The association cannot be explained by demographic or cardiovascular risk factors. This may have implications in the aetiopathology of atherosclerosis.

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^☆: A Letter to the Editor regarding this paper should be viewed at the following doi:10.1016/j.atherosclerosis.2009.03.021

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Greater adverse effects of cholesterol and diabetes on carotid intima–media thickness in South Asian Indians: Comparison of risk factor-IMT associations in two population-based surveys☆

Abstract

Introduction

Section snippets

Methods

Participant characteristics

Discussion

Conflict of interest

Acknowledgements

Lancet

Int J Cardiol

Diabetes Res Clin Pract

J Am Coll Cardiol

J Am Coll Cardiol

Lancet

Am Heart J

Atherosclerosis

What is the risk of coronary heart disease in South Asians? A review of UK research

J Public Health Med

Cardiovascular and cancer mortality among Canadians of European, south Asian and Chinese origin from 1979 to 1993, an analysis of 1.2 million deaths

Can Med Assoc J

Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. I. Differences in mortality

J Epidemiol Commun Health

Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. II. Differences in risk factor levels

J Epidemiol Commun Health

Prediction of clinical cardiovascular events with carotid intima–media thickness: a systematic review and meta-analysis

Circulation

Association of coronary heart disease incidence with carotid arterial wall thickness and major risk factors: the Atherosclerosis Risk in Communities (ARIC) Study, 1987–1993

Am J Epidemiol