Lipoprotein(a)is an important genetic risk for coronary artery disease in Asian Indians

Prediction and early detection of cardiovascular disease in South Asians with diabetes mellitus

BACKGROUND

Although diabetes mellitus (DM) is no longer considered "coronary heart disease risk equivalent", the risk remains sufficiently high, necessitating early recognition and management of cardiovascular disease (CVD) in these patients. Despite this understanding, the optimum strategy for prediction and early detection of CVD in DM remains debatable.

METHODS

Major societal guidelines for prediction and evaluation of CVD in subjects with or without DM were reviewed. Available evidence about various risk stratification strategies-their advantages, disadvantages and current role in clinical practice-were extensively reviewed. Special emphasis was placed on evidence from South Asian/Indian populations.

RESULTS

The inconsistency and variability inherent to the clinical risk algorithms, lack of consensus regarding the incremental value of subclinical atherosclerosis imaging and the lack of sufficient data to demonstrate the benefits of recognizing asymptomatic atherosclerotic disease are some of the reasons underlying prevailing uncertainty about the optimum approach for cardiovascular risk assessment in DM. These challenges notwithstanding, an evidence-based cardiovascular risk stratification strategy incorporating clinical risk algorithms, biomarkers, atherosclerosis imaging, and cardiac stress testing is proposed.

CONCLUSIONS

The proposed algorithm should help clinicians in optimizing cardiovascular evaluation and management of their patients with DM. However, this remains a dynamic field; further research into different risk assessment tools, esp. focusing on their impact on improving clinical outcomes, should help refine the evaluation strategy in future.

South Asian Cardiovascular Disease & Cancer Risk: Genetics & Pathophysiology

South Asians (SAs) are at heightened risk for cardiovascular disease as compared to other ethnic groups, facing premature and more severe coronary artery disease, and decreased insulin sensitivity. This disease burden can only be partially explained by conventional risk factors, suggesting the need for a specific cardiovascular risk profile for SAs. Current research, as explored through a comprehensive literature review, suggests the existence of population specific genetic risk factors such as lipoprotein(a), as well as population specific gene modulating factors. This review catalogues the available research on cardiovascular disease and genetics, anthropometry, and pathophysiology, and cancer genetics among SAs, with a geographical focus on the U.S. A tailored risk profile will hinge upon population customized classification and treatment guidelines, informed by continued research.

An Examination of Stroke Risk and Burden in South Asians

BACKGROUND

South Asians (India, Pakistan, Sri Lanka, Bangladesh, Nepal, and Bhutan) are at a disproportionately higher risk of stroke and heart disease due to their cardiometabolic profile. Despite evidence for a strong association between diabetes and stroke, and growing stroke risk in this ethnic minority-notwithstanding reports of higher stroke mortality irrespective of country of residence-the explanation for the excess risk of stroke remains unknown.

METHODS

We have used extensive literature review, epidemiologic studies, morbidity and mortality records, and expert opinions to examine the burden of stroke among South Asians, and the risk factors identified thus far.

RESULTS

We summarize existing evidence and indicate gaps in current knowledge of stroke epidemiology among South Asian natives and immigrants.

CONCLUSIONS

This research focuses attention on a looming epidemic of stroke mainly due to modifiable risk factors, but also new determinants that might aggravate the effect of vascular risk factors in South Asians causing more disabling strokes and death.

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.

Molecular studies on coronary artery disease-a review

Coronary artery disease (CAD) remains the major cause of mortality and morbidity in the entire world population. The conventional risk factors of CAD include hypertension, hyperlipidemia, diabetes mellitus, family history, smoking etc. These factors contribute only 50 % of the total risk of CAD. For providing a complete risk assessment in CAD, it is mandatory to have well-planned clinical, biochemical and genetic studies in patients with CAD and subjects who are at risk of developing CAD. In this review an attempt is made to critically evaluate the conventional and emerging risk factors which predispose the individual to CAD. Specifically, the molecular basis of CAD including high oxidative stress, low antioxidant status and increased DNA damage are covered. A comprehensive and multifactorial approach to the problem is the better way to reduce the morbidity and mortality of the disease.

21-Year-old male with severe coronary atherosclerosis

Coronary heart disease (CHD) is not limited to middle-aged and elderly individuals; when premature CHD develops in the younger population, it has distinct characteristics in terms of lipid profile, risk factors, and clinical presentation. The following describes a 21-year-old male who presented with stable angina, underwent a full cardiac workup, and was ultimately found to have multivessel CHD. In summary, the presence of mild dyslipidemia, high blood pressure, cigarette smoking, obesity, and a family history was sufficient to induce ischemic heart disease at such a young age. <Learning objective: This case report reveals an exceptionally young Caucasian man presenting with stable angina and found to have multivessel coronary disease. The patient received a coronary artery bypass surgery at just 21 years of age. He exhibits traditional risk factors of CHD; hypertension, dyslipidemia, cigarette smoking, and obesity. CHD may be more prevalent in the younger population than once was thought, and it is important that risk factor reduction starts in early in life.>.

Asymmetric and symmetric dimethylarginine in patients presenting with risk factors for coronary heart disease

The aim of the present study was to investigate asymmetric (ADMA) and symmetric dimethylarginine (SDMA) production in patients presenting with one or more risk factor (RF) for coronary heart disease (CHD). Patients and methods: Overall, 113 participants were enrolled in the study, including 45 patients presenting with risk for CHD (27 male and 18 female; aged 55.9 ± 6.4 years), 30 sex and age-matched middle-aged healthy controls (16 male and 14 female; aged 56.3 ± 8.4 years), and 38 young healthy controls (38 male; aged 24.6 ± 3.9 years). Results: No significant differences for ADMA and SDMA were recorded between patients groups presenting with risk for CHD. However, ADMA and SDMA were significantly higher in all examined patient groups (≥3 and 1–2 RF, hypertensive and non-hypertensive, obese and non-obese, diabetics and non-diabetics) compared with both control groups (middle-aged and young controls) (p<0.001). ADMA significantly correlated with SDMA in ≥3 RF (p<0.05), hypertensive (p<0.05), non-obese (p<0.05), non-diabetics (p<0.01), as well in middle-aged (p<0.05) and young controls (p<0.001). Conclusion: Significantly higher ADMA and SDMA were found between patients presenting with risk for CHD (≥3 and 1–2 RF, hypertensive and nonhypertensive, obese and non-obese, diabetics and non-diabetics) and healthy, middle-aged and young controls. ADMA significantly correlated with SDMA in ≥3 RF, hypertensive, non-obese and non-diabetic patients, as well as in middle-aged and young controls.

Receptor for advanced glycation end products (RAGE) and its inflammatory ligand EN-RAGE in non-diabetic subjects with pre-mature coronary artery disease

OBJECTIVE

Inflammation participates in atherosclerosis from its inception onwards. RAGE (receptor for advanced glycation end products) and its natural pro-inflammatory ligand, EN-RAGE (extracellular newly identified RAGE-binding protein) have been implicated in various inflammatory diseases. In present study, we determined the expression of RAGE and EN-RAGE in peripheral blood mononuclear cells (PBMCs) of subjects with pre-mature coronary artery disease (CAD) for the first time.

METHODS AND RESULTS

The study patients were angiographically proven non-diabetic patients with pre-mature CAD (Group I; N=100) and control group comprised of subjects with coronary risk factors and without coronary artery lesions (Group II; N=40). Semi-quantitative RT-PCR was performed to determine transcriptional expression of RAGE and EN-RAGE in PBMCs. Soluble RAGE (sRAGE) and C-reactive protein (hsCRP) levels were determined in serum of all study subjects using immunoassays. A significantly increased transcriptional expression of RAGE and EN-RAGE in PBMCs (p<0.01) of Group I patients was observed. Increased circulating hsCRP (p<0.01) levels and decreased sRAGE (p<0.01) levels were observed in Group I as compared with the Group II subjects. Severity of disease determined by Gensini score was found to be positively correlated with transcriptional expression of RAGE (r=0.530) and EN-RAGE (r=0.323). EN-RAGE expression revealed a strong association with RAGE (r=0.326), hsCRP (r=0.251) and a negative association with sRAGE (r=-0.222).

CONCLUSIONS

Increased expression of RAGE and EN-RAGE in non-diabetic pre-mature CAD and various associations discussed may amplify several cellular perturbations and thus significantly contribute to the pathophysiology of CAD.

Correlation among soluble markers and severity of disease in non-diabetic subjects with pre-mature coronary artery disease

Studies are lacking in literature, which demonstrate the cumulative impact of certain soluble markers in predicting the severity of CAD. Serum hsCRP, MMP-9, TIMP-1 and sRAGE levels were measured in non-diabetic 100 angiographically proven CAD patients (Group I) and 40 non-diabetic subjects with coronary risk factors and without any lesions (Group II). Increased levels of serum hsCRP, MMP-9, TIMP-1 and decreased levels of sRAGE were observed in Group I as compared to Group II. Gensini score, a measure for severity of CAD was found to be positively correlated with serum hsCRP, MMP-9, TIMP-1 and negatively with sRAGE. Multivariate analysis revealed serum MMP-9, hsCRP, sRAGE and family history as predictors of severity of CAD with a cumulative sensitivity and specificity of 92% and 82%, respectively. Cumulative impact of these soluble markers, in addition to the established markers will contribute to improve the predictive value for the assessment of disease severity.

Lifestyle of Asian Indians with coronary heart disease: the Australian context

This paper aims to report lifestyle factors of Asian Indians in Australia in relation to coronary heart disease. This issue has not been previously explored in the Australian context. This study also seeks to identify factors that could inform health education and rehabilitation programs for migrant Asian Indians in Australia. The qualitative descriptive approach of constructivism was used for this study. Semi-structured, in-depth conversations were conducted with eight patients and five family members. Participants were at risk for coronary heart disease either due to unhealthy diet and/or lack of physical exercise and irregular health checks. Although lifestyle modifications were implemented by participants after the cardiac event; these changes were implemented inconsistently and without continuity. Knowledge of the beneficial effects of a healthy diet did not deter the participants from continuing to follow unhealthy dietary habits. The introduction of any exercise or physical activity by participants in this study lacked consistency. A positive aspect revealed from this study was the influence of culture and religious faith, which helped patients and family members to cope with the illness trajectory. The results of this study suggest that health education and rehabilitation programs need to be designed specifically for this high-risk group would be beneficial when initiated early in life and need to be targeted to the individual.

Prevalence of diabetic complications in fibrocalculous pancreatic diabetic patients and type 2 diabetic patients: a cross-sectional comparative study

OBJECTIVE

To determine the prevalence of diabetes-related complications in subjects with fibrocalculous pancreatic diabetes (FCPD) and compare them with subjects with type 2 diabetes mellitus matched for age, sex, and duration of diabetes.

METHODS

The study group comprised of 277 FCPD patients and 277 age, sex, and duration of diabetes-matched type 2 diabetic patients. All the study subjects underwent a detailed clinical examination, and fasting blood samples were obtained for biochemical studies. Peripheral Doppler was used for diagnosis of peripheral vascular disease (PVD). Vibratory perception threshold (VPT) was determined using biothesiometry for diagnosis of neuropathy. Diagnosis of coronary artery disease (CAD) was based on medical history and 12-lead resting ECG. Retinal photographs were used for diagnosis of retinopathy using a modified version of Early Treatment Diabetic Retinopathy Study (ETDRS) grading system.

RESULTS

FCPD patients had lower body mass index (BMI) (P<.001), systolic blood pressure (P<.0001), diastolic blood pressure (P<.001), serum cholesterol (P<.001), serum triglyceride (P<.001), and serum creatinine (P<.01) but higher glycosylated hemoglobin (P<.001) levels compared to patients with type 2 diabetes. Prevalence of CAD was significantly higher among type 2 diabetic patients (11.9%) compared to FCPD patients (5.1%), P<.003. There was no significant difference in the prevalence of other diabetic complications between the two study groups (type 2 diabetes vs. FCPD: retinopathy-37.2% vs. 30.1%, PVD-4.3% vs. 4.7%, Neuropathy-25.3% vs. 20.9%, Nephropathy-15.0% vs. 10.1%). Multiple logistic regression analysis revealed the following risk factors for diabetes complications among type 2 diabetic subjects-retinopathy: BMI (P=.028), duration of diabetes (P<.001), and glycosylated hemoglobin (P=.026); nephropathy: diastolic blood pressure (P=.016) and glycosylated hemoglobin (P=.040); neuropathy: age (P<.001), duration of diabetes (P=.003), and glycosylated hemoglobin (P=.001). Among subjects with FCPD, systolic blood pressure (P=.013), glycosylated hemoglobin (P=.021), and duration of diabetes (P<.001) were associated with retinopathy; BMI (P=.057), glycosylated hemoglobin (P=.010), and duration of diabetes (P=.024) with nephropathy and age (P=.011) and BMI (P=.010) with neuropathy.

CONCLUSION

The prevalence of retinopathy, nephropathy, neuropathy, and PVD was similar among FCPD patients and type 2 diabetic patients, but the prevalence of CAD was lower among FCPD patients.

Ethnic trends in lipid tests in general practice

BACKGROUND

South Asian migrants have a higher cardiovascular mortality than the indigenous population. Contributory factors may include a lower rate of cardiovascular risk assessment uptake and compliance.

AIM

To compare rates of lipid testing, follow-up and patterns of dyslipidaemia in South Asian and non-South-Asian populations in Manchester.

DESIGN

Retrospective cross-sectional survey.

METHODS

Lipid requests from 14 general practices were analysed, using name recognition software to assign ethnicity.

RESULTS

Compared with non-South-Asians, the age-standardized rate of lipid testing in South Asians was similar in men at 12.1% (95%CI 11.6-12.6) vs. 11.2% (9.5-13.0), but higher in women at 18.6% (15.9-21.2) vs. 13.2% (12.6-13.7). Trends of cholesterol with repeat testing were similar in the two populations. However, South Asian women had lower mean levels of total cholesterol (5.50 vs. 5.68 mmol/l, p = 0.021), lower levels of HDL (1.20 vs. 1.46 mmol/l, p < 0.001), an excess of hypertriglyceridaemia (1.62 vs. 1.45 mmol/l, p = 0.035) and a greater proportion with cholesterol > 5.2 mmol/l combined with low HDL (43.1% vs. 20.2%, p = 0.002). South Asian men had lower levels of total cholesterol (5.17 vs. 5.37 mmol/l, p = 0.048) and lower levels of HDL (1.07 vs. 1.64 mmol/l, p < 0.001). There was no difference in the proportion of South Asians men and women with cholesterol < 5.2 mmol/l combined with low HDL.

DISCUSSION

The rate of lipid testing and change in cholesterol levels with repeated testing did not differ between South Asian and non-South-Asian groups. The pattern of dyslipidaemia seen in this South Asian population, especially women, was different from that of the non-South-Asian population, with possible implications for cardiovascular risk assessment.

Relationship of lipoprotein(a) with intimal medial thickness of the carotid artery in Type 2 diabetic patients in south India

OBJECTIVE

The objective of this study was to investigate the association of lipoprotein(a) [Lp(a)] levels with intimal medial thickness (IMT) in Type 2 diabetic patients in south India.

STUDY DESIGN

We studied 587 consecutive Type 2 diabetic patients at the M.V. Diabetes Specialities Centre, Chennai. The mean age of the study group was 55 +/- 10 years and 71.2% were males. IMT of the right common carotid artery was determined using high-resolution B mode ultrasonography. Lp(a) levels were measured using ELISA. Since the frequency distribution of Lp(a) was skewed, Lp(a) values were log transformed and the geometric mean was used for statistical analysis. The tertiles of IMT were determined to analyse the association of Lp(a) and other factors with IMT.

RESULT

The mean Lp(a) level in the study patients was 18.9 +/- 3.1 mg/dl (geometric mean +/- sd) and the mean IMT of the study subjects was 0.93 +/- 0.19 mm (mean +/- sd). The prevalence of carotid atherosclerosis (defined as IMT > 1.1 mm) among subjects with elevated Lp(a) levels > 20 mg/dl was significantly higher compared with those with Lp(a) levels </= 20 mg/dl (26.9% vs. 16.3%, P = 0.003). Lp(a) levels increased with increase in tertiles of IMT (anova, P < 0.05). Pearson correlation analysis of carotid IMT with other cardiovascular risk factors revealed strong correlation of IMT with age (P < 0.0001), duration of diabetes (P < 0.0001), systolic blood pressure (P < 0.0001), diastolic blood pressure (P = 0.006), LDL-cholesterol (P = 0.023), HbA1c (P = 0.017) and Lp(a) (P < 0.0001). Multiple logistic regression analysis showed age (P = 0.010), LDL-cholesterol (P = 0.032) and Lp(a) (P = 0.021) to be associated with carotid atherosclerosis.

CONCLUSION

The results suggest that Lp(a) has a strong association with IMT of carotid arteries in Type 2 diabetic subjects in south India.