The prevalence of ischaemic heart disease risk factors in middle-aged White miners.

: The prevalence of ischaemic heart disease (IHD) risk factors was studied in a random sample of 3930 White miners, aged 45 - 62 years, of whom 202 had evidence of a definite or probable myocardial infarct (MI) on electrocardiographic and chest pain criteria. Ninety-two were classified as "suspect" MI cases and were excluded from the study. The prevalence of the major IHD risk factors (mildly elevated serum total cholesterol levels and blood pressure, and cigarette-smoking) in the 3636 White miners who had not had Mls did not differ from those in comparable populations in the UK, USA and Australia, nor did those of secondary IHD risk factors (elevated blood glucose and plasma uric acid levels and being overweight) differ in the various populations. There was, however, a relatively high percentage of middle-aged White miners with two (25.2%) and three (4.4%) simultaneous IHD risk factors. Such men have a much higher probability of an MI within 8 years than men with no IHD risk factors. This study indicates that 770 out of every 1000 middle-aged White miners would have one or more major IHD risk factors; of these, 252 would have two risk factors and 44 three risk factors. This finding points to the urgent need for an intervention programme for the early detection and prevention of IHD risk factors.