Coronary Artery Disease and Coronary Risk Factors: The South Asian Paradox

Nutrition transition in South Asia: the emergence of non-communicable chronic diseases

Overview: South Asian countries have experienced a remarkable economic growth during last two decades along with subsequent transformation in social, economic and food systems. Rising disposable income levels continue to drive the nutrition transition characterized by a shift from a traditional high-carbohydrate, low-fat diets towards diets with a lower carbohydrate and higher proportion of saturated fat, sugar and salt. Steered by various transitions in demographic, economic and nutritional terms, South Asian population are experiencing a rapidly changing disease profile. While the healthcare systems have long been striving to disentangle from the vicious cycle of poverty and undernutrition, South Asian countries are now confronted with an emerging epidemic of obesity and a constellation of other non-communicable diseases (NCDs). This dual burden is bringing about a serious health and economic conundrum and is generating enormous pressure on the already overstretched healthcare system of South Asian countries.

Objectives: The Nutrition transition has been a very popular topic in the field of human nutrition during last few decades and many countries and broad geographic regions have been studied. However there is no review on this topic in the context of South Asia  as yet. The main purpose of this review is to highlight the factors accounting for the onset of nutrition transition and its subsequent impact on epidemiological transition in five major South Asian countries including Bangladesh, India, Nepal, Pakistan and Sri Lanka. Special emphasis was given on India and Bangladesh as they together account for 94% of the regional population and about half world’s malnourished population.

Methods: This study is literature based. Main data sources were published research articles obtained through an electronic medical databases search.

South Asians and Anglo Australians with heart disease in Australia

Objectives The aim of the present study was to determine cardiovascular disease (CVD) risk factors and compare presentation and severity of ischaemic heart disease (IHD) among South Asians (SAs) and Anglo Australians (AAs). Methods A retrospective clinical case audit was conducted at a public tertiary hospital. The study population included SA and AA patients hospitalised for IHD. Baseline characteristics, evidence of diabetes and other CVD risk factors were recorded. Angiography data were also included to determine severity, and these were assessed using a modified Gensini score. Results SAs had lower mean (± s.d.) age of IHD presentation that AAs (52 ± 9 vs 55 ± 9 years, respectively; P = 0.02), as well as a lower average body mass index (BMI; 26 ± 4 vs 29 ± 6 kg/m2, respectively; P = 0.005), but a higher prevalence of type 2 diabetes (57% vs 31%, respectively; P = 0.001). No significant differences were found in coronary angiography parameters. There were no significant differences in the median (interquartile range) Gensini score between SAs and AAs (43.5 (27–75) vs 44 (26.5–68.5), respectively), median vessel score (1 (1–2) vs 2 (1–3), respectively) or multivessel score (37% (33/89) vs 54% (22/41), respectively). Conclusions The findings show that in those with established IHD, cardiovascular risk factors, such as age at onset and BMI, differ between SAs and AAs and these differences should be considered in the prevention and management of IHD. What is known about the topic? There is much evidence on CVD and SAs, it being a leading cause of mortality and morbidity for this population both in their home countries and in countries they have migrated to. Studies conducted in Western nations other than Australia have suggested a difference in the risk profiles and presentations of CVD among SA migrants compared with the host populations in developed countries. Although this pattern of cardiovascular risk factors among SAs has been well documented, there is insufficient knowledge about this population, currently the largest population of incoming migrants, and CVD in the Australian setting. What does this paper add? This paper confirms that a similar pattern of CVD exists in Australia among SAs as does in other Western nations they have migrated to. The CVD pattern found in this population is that of an earlier age of onset at lower BMI compared with the host AA population, as well as a differing cardiovascular risk profile, with higher rates of type 2 diabetes and lower smoking rates. In addition, this study finds similar angiographic results for both the SAs and AAs; however, the SAs exhibit these similar angiographic patterns at younger ages. What are the implications for practitioners? SAs in Australia represent a high cardiovascular risk group and should be targeted for more aggressive screening at younger ages. Appropriate preventative strategies should also be considered bearing in mind the differing risk factors for this population, namely low BMI and high rates of type 2 diabetes. More intensive treatment strategies should also be regarded by practitioners. Importantly, both policy makers and health professionals must consider that all these strategies should be culturally targeted and tailored to this population and not assume a ‘one-size fits all’ approach.

Metabolic syndrome: a brain disease

Recent research indicates an association between brain dysfunction and the pathogenesis of metabolic syndrome. To investigate this, we created a Medline search (up to December 2011) of articles in PubMed. The results indicated that refined carbohydrates, saturated and total fat, high levels of ω-6 fatty acids, and low levels of ω-3 fatty acids and other long chain polyunsaturated fatty acids (PUFA), all in conjunction with sedentary behaviour and mental stress can predispose to inflammation. Increased sympathetic activity, with increased secretion of catecholamine, cortisol, and serotonin can cause oxidative stress, which may damage the arcuate nucleus as well as the hypothalamus and macrophages, and the liver may release pro-inflammatory cytokines. These, in conjunction with an underlying deficiency in long chain PUFA, may damage the arcuate nucleus as well as neuropeptide-Y and pro-opiomelanocortin neurons and insulin receptors in the brain, especially during fetal life, infancy, and childhood, resulting in their dysfunction. Of the fatty acids in the brain, 30%-50% are long chain PUFA, which are incorporated in the cell membrane phospholipids. Hence, ω-3 fatty acids, which are also known to enhance parasympathetic activity and increase the secretion of anti-inflammatory cytokines interleukin (IL)-4 and IL-10 as well as acetylcholine in the hippocampus, may be protective. Therefore, treatment with ω-3 fatty acids may be applied for the prevention of metabolic syndrome.

Relationship of metabolic syndrome with quantum of coronary artery disease in Indian patients with chronic stable angina

BACKGROUND

The current study was aimed to ascertain presence and severity of coronary artery lesions in patients of Type 2 diabetic mellitus (DM) with coronary artery disease (CAD), in our population, by using scoring system analysis of the coronary angiography.

METHODS

147 consecutive patients with Type 2 DM of chronic stable angina (CSA) were enrolled in the study with 147 age- and sex-matched patients of CSA who did not have diabetes to serve as control. All of them underwent coronary angiography and were evaluated by using four scores to quantify the coronary artery lesions. The scores analyzed were coronary score, extent score, severity score, and atherosclerosis score. Other major risk factors such as smoking and hypertension lipid profile were also evaluated.

RESULTS

Type 2 diabetics with CAD had higher coronary score (0.91 +/- 0.63 in diabetics vs. 0.43 +/- 0.39, p < 0.001), extent score (4.91 +/- 3.1 vs. 2.3 +/- 1.8, p < 0.001), severity score (1.85 +/- 0.41 vs. 1.2 +/- 0.32, p < 0.001), and atherosclerosis score (0.52 +/- 0.31 vs. 0.21 +/- 0.26, p < 0.001) as compared to non-diabetics with CAD. Left main stem involvement, 2-vessel disease, and 3-vessel disease were also more frequent in the diabetics. These diabetes also had higher incidence of obesity, hypertension, and dyslipidemia.

CONCLUSIONS

In our population, diabetics suffer from higher prevalence of diffuse and extensive coronary atherosclerosis. The grades of stenosis in coronary arteries are also higher in diabetic patients when compared with non-diabetics with CAD, as was the prevalence of other components of the metabolic syndrome.

Prevalence of coronary artery disease risk factors in Iran: a population based survey

BACKGROUND

Coronary artery disease (CAD) is a leading cause of mortality, morbidity, and disability with high health care cost in Iran. It accounts for nearly 50 percent of all deaths per year. Yet little is known about CAD and CAD risk factors in the Iranian population. We aimed to assess the prevalence of different CAD risk factors in an Iranian population.

METHODS

A descriptive cross sectional survey was conducted involving 3000 healthy adults at 18 years of age or above who were recruited with cluster random sampling. Demographic data and risk factors were determined by taking history, physical examination and laboratory tests.

RESULTS

The average age was 36.23 +/- 15.26. There was 1381 female (46%) and 1619 male (54%) out of which 6.3% were diabetic, 21.6% were smoker, and 15% had positive familial heart disease history. 61% had total cholesterol level > 200 mg/dL, 32% triglyceride > 200 mg/dl, 47.5% LDL-c > 130 mg/dl, 5.4% HDL-c < 35 mg/dl, 13.7% systolic blood pressure > 140 mmHg, 9.1% diastolic blood pressure > 90 mmHg and 87% of them were physically inactive.

CONCLUSION

Clinical and Para-clinical data indicated that Iranian adult population are of a high level of CAD risk factors, which may require urgent decision making to address national control measures regarding CAD.

Can brain dysfunction be a predisposing factor for metabolic syndrome?

The various mechanisms that may explain the association between brain dysfunction and the pathogenesis of metabolic syndrome (MS) leading to cardiovascular disease and type 2 diabetes have been reviewed. A Medline search was conducted until September 2003, and articles published in various national and international journals were reviewed. Experts working in the field were also consulted. Compelling evidence was found that saturated and total fat and low dietary n-3 fatty acids and other long-chain polyunsaturated fatty acids (PUFAs) in conjunction with sedentary behavior and mental stress combined with various personality traits can enhance sympathetic activity and increase the secretion of catecholamine, cortisol and serotonin, all of which appear to be underlying mechanisms involved in MS. Excess secretion of these neurotransmitters in conjunction with underlying long-chain PUFA deficiency may damage the neurons in the ventromedial hypothalamus and insulin receptors in the brain, in particular during fetal life, infancy and childhood, and lead to their dysfunction. Since 30-50% of the fatty acids in the brain are long-chain PUFAs, especially omega-3 fatty acids which are incorporated in the cell membrane phospholipids, it is possible that their supplementation may have a protective effect. Omega-3 fatty acids are also known to enhance parasympathetic activity and to increase the secretion of anti-inflammatory cytokines as well as acetylecholine in the hippocampus. It is possible that a marginal deficiency of long-chain PUFAs, especially n-3 fatty acids, due to poor dietary intake during the critical period of brain growth and development in the fetus, and later in the infant and also possibly in the child, adolescent and adult may enhance the release of tumor necrosis factor-alpha (TNF-alpha) interleukin (IL)-1, 2 and 6 and cause neuronal dysfunction. Experimental studies indicate that ventromedial hypothalamic lesions in rats induce hyperphagia, resulting in glucose intolerance and insulin resistance. Treatment with neuropeptide Y abolished hyperphagia and ob mRNA (leptin mRNA) in this animal model. Long-term infusion of norepinephrine and serotonin into the ventromedial hypothalamus impaired pancreatic islet function inasmuch as ventromedial hypothalamic norepinephrine and serotonin levels were elevated in hyperinsulinemic and insulin-resistant animals. Treatment with insulin was associated with restoration of hypothalamic neurotransmitter abnormalities, indicating that ventromedial hypothalamus dysfunction can impair pancreatic beta cells resulting in metabolic abnormalities consistent with MS. Treatment with omega-3 fatty acids, beta blockers, ACE inhibitors, estrogen, and meditation may have a beneficial effect on insulin receptors and ventromedial hypothalamic dysfunction. However, no definite or precise insight into the pathophysiological link between MS, brain function and nutrition is available. Despite this, epidemiological studies and intervention trials indicate that treatment with n-3 fatty acids may be adopted in clinical practice and used to direct therapy for prevention of type 2 diabetes, hypertension, coronary artery disease (CAD), and atherosclerosis, thereby indicating that MS may also respond to this treatment.

Chronomics: circadian and circaseptan timing of radiotherapy, drugs, calories, perhaps nutriceuticals and beyond

We suggest a putative benefit from timing nutriceuticals (substances that are both nutrients and pharmaceuticals) such as antioxidants for preventive or curative health care, based on the proven merits of timing nutrients, drugs, and other treatments, as documented, i.a., in India. The necessity of timing melatonin, a major antioxidant, is noted. A protocol to extend the scope of chronoradiotherapy awaits testing. Imaging in time by mapping rhythms and broader time structures, chronomes, for earliest diagnoses, for example detection of vascular disease risk, is recommended. The study of rhythms and broader chronomes leads to a dynamic functional genomics, guided by imaging in time of free radicals and antioxidants, amongst many other variables.

Coronary artery disease in the developing world

BACKGROUND

Coronary artery disease (CAD) is the leading cause of cardiovascular mortality worldwide, with >4.5 million deaths occurring in the developing world. Despite a recent decline in developed countries, both CAD mortality and the prevalence of CAD risk factors continue to rise rapidly in developing countries. The objectives of the current article are to review (1) the literature regarding CAD mortality and the prevalence of CAD risk factors in the developing world, and (2) prevention and control measures.

METHODS

We conducted a MEDLINE search of the English language literature for the years 1990 to 2002 to identify articles pertaining to the prevalence of CAD in developing countries. The search was performed using the following key terms: coronary artery disease, developing countries, ischemic heart disease, incidence, prevalence, prevention and risk factors. We also obtained relevant statistical information from The World Health Organization's Internet database.

RESULTS

There is a paucity of data regarding CAD and its prevalence in the developing world. However, it is projected that CAD mortality rates will double from 1990 to 2020, with approximately 82% of the increase attributable to the developing world. Existing data suggest that rapid socioeconomic growth in developing countries is increasing exposure to risk factors for CAD, such as diabetes, genetic factors, hypercholesterolemia, hypertension, and smoking. There is a relative lack of prevention and control measures to decrease exposure to these risk factors in developing countries.

CONCLUSION

Documented information on the prevalence of CAD in developing countries is sparse, but there is sufficient data to suggest an impending epidemic. Prevention and targeted control of risk factors for CAD could potentially reduce the impact of CAD in the developing world as it has in industrialized nations.

Effect of an Indo-Mediterranean diet on progression of coronary artery disease in high risk patients (Indo-Mediterranean Diet Heart Study): a randomised single-blind trial

BACKGROUND

The rapid emergence of coronary artery disease (CAD) in south Asian people is not explained by conventional risk factors. In view of cardioprotective effects of a Mediterranean style diet rich in alpha-linolenic acid, we assessed the benefits of this diet for patients at high risk of CAD.

METHODS

We did a randomised, single-blind trial in 1000 patients with angina pectoris, myocardial infarction, or surrogate risk factors for CAD. 499 patients were allocated to a diet rich in whole grains, fruits, vegetables, walnuts, and almonds. 501 controls consumed a local diet similar to the step I National Cholesterol Education Program (NCEP) prudent diet.

FINDINGS

The intervention group consumed more fruits, vegetables, legumes, walnuts, and almonds than did controls (573 g [SD 127] vs 231 g [19] per day p<0.001). The intervention group had an increased intake of whole grains and mustard or soy bean oil. The mean intake of alpha-linolenic acid was two-fold greater in the intervention group (1.8 g [SD 0.4] vs 0.8 g [0.2] per day, p<0.001). Total cardiac end points were significantly fewer in the intervention group than the controls (39 vs 76 events, p<0.001). Sudden cardiac deaths were also reduced (6 vs 16, p=0.015), as were non-fatal myocardial infarctions (21 vs 43, p<0.001). We noted a significant reduction in serum cholesterol concentration and other risk factors in both groups, but especially in the intervention diet group. In the treatment group, patients with pre-existing CAD had significantly greater benefits compared with such patients in the control group.

INTERPRETATION

An Indo-Mediterranean diet that is rich in alpha-linolenic acid might be more effective in primary and secondary prevention of CAD than the conventional step I NCEP prudent diet.