Content of magnesium in drinking water and deaths from ischaemic heart disease in white South Africans.

Mortality rates for acute myocardial infarction and ischaemic heart disease (IHD) of white males and females in South Africa are much higher than those in the USA, Australia, England and Wales when individuals in the 15- to 64-year age group are considered. Magnesium levels in the drinking water of 12 South African districts and deaths due to IHD assessed on the basis of corrected statistics for deaths apparently due to IHD in white residents were studied and a significant negative correlation was found between these two variables. No such correlation has been demonstrated in blacks.