Epidemiology of ischaemic heart disease in India with special reference to causation.

Because of important geographical differences in its prevalence, not only between different coun- tries but even within a single country, ischaemic heart disease is thought to be due to the interplay of many factors, most of which are environmental. The dietary trend is one and the decline of physical activity is another, each of which is believed to play a major role. Several other factors, such as smok- ing (Doll and Hill, 1956), stress (Hammarsten et al., 1957), and softness or hardness of water (Schroeder, 1960) have also been incriminated.