Avoiding premature coronary deaths in Asians in BritainBMJ 1995; 311 doi: https://doi.org/10.1136/bmj.311.7012.1035 (Published 21 October 1995) Cite this as: BMJ 1995;311:1035
- Sandeep Gupta, British Heart Foundation junior research fellow in cardiology,
- Adam de Belder, Senior registrar in cardiology,
- Liam O Hughes, Consultant cardiologist
- Department of Cardiological Sciences, St George's Hospital Medical School, London SW17 ORE
- King's Healthcare Trust, London SE5 9RS
- Norfolk and Norwich Healthcare Trust, Norwich NRI 3SR
Spend now on prevention or pay later for treatment
Over 1.5 million people have settled in Britain from the Indian subcontinent (India, Pakistan, and Bangladesh) and east Africa.1 Epidemiological studies have shown that, irrespective of regional, cultural, and religious differences, immigrant south Asians all share a significantly higher mortality from coronary heart disease than the indigenous white population.2 3 4 This increased risk also applies to second generation Asian immigrants who have adverse risk factor profiles for coronary heart disease.5 First recognised in Singapore,6 this increase is a worldwide phenomenon.7 8
In 1977 a 40% excess incidence of myocardial infarction was found among Asians admitted to hospitals in Leicester,9 and more recently a group from Northwick Park Hospital found that Gujarati Asian men had four times the risk of a first myocardial infarction compared with north European men.10 This study also reported that the Asian men were significantly younger at the time of their first infarct, had more extensive atheroma, and had lower mean cholesterol concentrations than white men.
Whether the prevalence and incidence of coronary heart disease in Asians living in the Indian subcontinent differ from those in Asians abroad is uncertain. One small study showed no significant differences in risk profiles or extent of coronary disease between Asian men settled in Britain and an age matched population living in India.11 The authors went on to suggest that factors other than those related to migration and environment may be relevant.12 The viewpoint, however, contrasts with new evidence from a study comparing the coronary risk factors in a group of Punjabi Asian migrants settled in west London with their siblings living in Punjab District, India. Its findings suggest that Asians are genetically predisposed to atherothrombotic risk factors, which migration and westernisation unmask and potentiate.13 None the less, as rates of coronary heart disease in India vary greatly depending on location14 and socioeconomic status,15 comparison between British Asians with Indian Asians is difficult.
Asian women are not spared the increased risk. Mortality from coronary heart disease increased by 8% in Asian men and 14% in Asian women from 1970 to 1985; at the same time overall mortality fell in all western European countries.2 16 The excess coronary heart disease in Asians cannot be explained by differences in conventional risk factors such as increased total cholesterol concentration, hypertension, and smoking.4 However, non-insulin dependent diabetes is more common in Indians, and high plasma triglyceride and lipoprotein(a) concentrations and low high density lipoprotein cholesterol concentrations predominate in Asians. Paradoxically, diabetes is widespread among Britain's Afro-Caribbean population yet its rate of coronary heart disease is low.
Insulin resistance may explain the unfavourable metabolic profile among Asians.17 18 Increased fasting and post-glucose serum insulin concentrations, even in non-diabetic subjects, have been found in British Asians compared with Europeans and Afro-Caribbeans. These raised concentrations correlate strongly with central obesity (an increased waist to hip ratio) among the Asian group. Furthermore, central obesity and insulin resistance correlate strongly with high fasting triglyceride concentrations and with failure of triglyceride concentrations to fall after a glucose load in both Asian men and women.18 Suggested mechanisms include the failure of insulin to suppress release of non-esterified fatty acids from intra-abdominal fat cells19 and altered hepatic insulin metabolism and peripheral glucose uptake in the presence of central obesity.20 Insulin concentrations may also affect haemostatic risk factors for coronary heart disease, including fibrinogen, factor VIIc, and plasminogen activator-1 concentrations,21 and may directly promote atherogenesis by stimulating the proliferation of vascular smooth muscle cells.22
The striking tendency for central obesity has been noted in both British and Indian Asians but confers a greater (independent) risk of coronary heart disease among British Asians12; among white people, central obesity seems to be associated with a significantly increased risk only in those with a constellation of hypertension, dyslipidaemias, and glucose intolerance.23 The modifiable influences on insulin resistance are dietary intake24 and physical activity.25 As groups adapted to survive under conditions of periodic famine and low energy intake, Hindus, Sikhs, and Muslims may develop central obesity as a consequence of migration and environment.18 A diet rich in saturated fats and energy (including ghee) and a sedentary lifestyle favour this development.
No doubt therefore exists about the disturbing problem of heart disease among Asians in Britain, but do solutions exist? Britain urgently needs a nationwide coronary health programme tailored to the specific problems of its migrant Asian population, but the Asian community must act for itself. Workers in primary and secondary health care and religious and community leaders should aim to increase awareness of modifiable cardiac risk factors among both sexes and all age groups in the Asian population. This could be organised through health centres, community meetings, schools, the ethnic media, and places of worship. Survivors of myocardial infarction and those who have undergone successful coronary revascularisation should relay their experiences to members of their community. Failure to seek prompt medical advice and delays in diagnosis and treatment among ethnic groups often result from language difficulties,26 and this issue also needs to be addressed.
General practitioners with a large proportion of patients from affected ethnic groups could set up “well Asian clinics” to identify subjects at high risk. Awareness of the risks could be increased by informing second generation Asians coming through the British educational system, who could convey the advice to their family and friends, as well as modify their own risk factors while young.
An effective campaign of primary prevention requires adequate central funding and planning. The Department of Health should consider issuing guidelines and highlighting targets for action. Dietary advice, particularly on restricting carbohydrates, needs to be sensitive. The food industry has a part to play by altering the fat content of food (for example, more monosaturates and n-3 fatty acids) and generally by promoting healthier, lower energy, and yet palatable products. Encouraging Asians to increase regular physical activity may be worth while and should be evaluated.
Unless something is done to reduce the risk of heart disease in the Asian population in Britain all indicators suggest that the problem will increase.5 Data from Leicester indicate that, by 2008, half its Asian population will be over 50 and, if their risk of coronary death remains 1.4 times that of the rest of the population the number of deaths from coronary heart disease will double.27 In other places with large Asian communities this will have a considerable impact on acute medical services. Spending now would make more medical and economic sense than paying later.