In the 1950's and early 1960's, there emerged a gradual awareness that people with ancestral origins in the Indian subcontinent (henceforth called South Asians) are highly susceptible to cardiovascular diseases after migration to urban environments. Adelstein reported that in South Africa mortality rates for cardiovascular disease in Asian (mainly Indian) men and women, were much higher than in white men and women, respectively. Such findings have been confirmed in several countries. In Britain, analysis of mortality rates around the censuses of 1971 by Marmot et al, 1981 by Balarajan et al and 1991 by Wild and McKeigue have shown a 15% - 60% excess in Indian Subcontinent born populations in comparison to the whole population of England and Wales. The validity of such data will be considered below but these data have confirmed the view that the cardiovascular diseases are the foremost killer of South Asians in Britain.

Coronary artery disease (CHD) is associated with industrialisation and modernisation of society. CHD was uncommon in Britain in the 19th century and when it became a major problem, the wealthy were affected more. Now CHD is the commonest cause of death and affects poorer people more. This time-trend has not been explained satisfactorily. While trends in South Asian populations remain unclear, there is some evidence of a decline in the absolute rates but an increase in the level of disparity in comparison to the whole population, a result of rapidly declining rates in the white, European origin populations. The association between low social class and higher cardiovascular mortality and risk factors has emerged in South Asians. CHD is still uncommon in many countries, particularly developing countries. There is a paucity of information on the frequency of CHD in the Indian subcontinent and seemingly it is uncommon in rural areas, but is a growing problem in the cities9. The epidemic in South Asians abroad forewarns of what may happen on the Indian Subcontinent.

Most middle aged and elderly British South Asians migrated here as young adults. Many came from rural or semi-urban areas at a time when CHD was not a common problem in India. There are two key questions about the rise of CHD in South Asians, first, why is the disease so unexpectedly common and, second, what can South Asians do to protect themselves?.

The cause of CHD, despite massive research, remains unclear. There is a general agreement that the factors in box 1.1 increase risk of CHD either directly or indirectly. However, CHD occurs even without these risk factors. The roles of stress, racism, inflammation, infection, specific dietary constituents such as the B vitamins and folic acid, and environmental pollution and many other risk factors as causes of CHD remain unclear.

The term South Asian, usually used to combine Indians, Pakistanis, Bangladeshis and sometimes Sri Lankans, defines many ethnic groups, with distinctive regions of origin, languages, religions and customs. Language impacts in obvious ways on clinical care and health promotion. Religion governs important health behaviours such as taboos on smoking (Sikhs in particular), alcohol (Muslims in particular) and dietary customs. Social customs include taboos on smoking, drinking and chewing of tobacco in women, the latter of which is nonetheless common in Bangladeshis. The prevalence of current smoking in male South Asians in Newcastle was 33% overall, but 14% in Indians, and 57% in Bangladeshis; and the prevalence of weekly aerobic activity was 22% overall, but 33% in Indians, 19% in Pakistanis and 14% in Bangladeshis. Such heterogeneity is clearly important in CHD.

Since smoking is a major risk factor for CHD we would expect South Asians, Sikhs and Hindus in particular to have lower CHD rates than average. However, the rates seem to be higher. This observation of a high CHD rate in South Asians, in the face of apparently lower prevalence of smoking and other major risk factors, and in the light of the low rate in the Indian Subcontinent, is a public health problem, one which is exciting and important for researchers. If the paradox can be explained we might gain more insight into the cause of CHD and refine strategies to prevent and control this disease in all populations.

Contents

List of Contributors
Foreword

Prof. L Donaldson
Prof. Sir C George
Lord N Patel

Preface KCR Patel and RS Bhopal
Acknowledgements
The South Asian Health Foundation
Glossary
Chapter 1: Coronary heart disease in South Asians: the scale of the problem and the challenge RS Bhopal
Chapter 2: Conceptualising the causes of coronary heart disease in South Asians J Kooner and J C Chambers
Chapter 3: Coronary heart disease in South Asians: the impact of type 2 diabetes mellitus JK Cruickshank, A Vyas, M Banerjee and JC Oldroyd
Chapter 4: Endothelial Dysfunction : underlying mechanisms and their relevance for coronary heart disease in South Asians A M Shah and M T Kearney
Chapter 5: Fetal and early life origins of cardiovascular disease in South Asians C Fall
Chapter 6: Coronary heart disease in South Asian populations - the role of genetics NJ Samani and P Sharma
Chapter 7: Inflammation and infection in coronary heart disease - a role in South Asians? S Gupta
Chapter 8: Nutrition and coronary heart disease in South Asians TAB Sanders
Chapter 9: Hypertension and coronary heart disease in South Asians C Agyemang and RS Bhopal 110
Chapter 10: Smoking and smoking cessation in South Asian communities Q Zaidi
Chapter 11: Physical activity among South Asians in Britain M White
Chapter 12: Poverty, stress and racism as factors in South Asian heart disease R Williams and S Harding
Chapter 13: Overview of South Asian coronary heart disease and the road ahead M Marmot

Download
PDF Ebook The Epidemic Of Coronary Heart Disease In South Asian Populations: Causes And Consequences