A retrospective sample of males in a heart-disease high-risk region
of the Western Cape, South Africa. There are roughly two controls per
case of CHD. Many of the CHD positive men have undergone blood
pressure reduction treatment and other programs to reduce their risk
factors after their CHD event. In some cases the measurements were
made after these treatments. These data are taken from a larger
dataset, described in Rousseauw et al, 1983, South African Medical
Journal.