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.