Family history, cigarette smoking and other risk factors in patients with myocardial infarction.

All patients entering a coronary care unit had data collected and stored prospectively on a computer file. Family history and risk factor data have been abstracted for those with confirmed myocardial infarction. These data are compared between those aged less than 50 years and those aged between 50 and 70 years. Cigarette smoking habits are compared with age matched data from the 1976 census population study of cigarette smoking habits. The risk factors of hypercholesteolaemia, obesity, diabetes, hypertension and cigarette smoking greater than 20 per day, do not separate the two age groups although cigarette smoking is more prevalent in the patient groups compared with the census population. Age of fathers' death is not different between the two age groups but death from myocardial infarction, presence of ischaemic heart disease during life in fathers and fewer nonsmokers in the younger age group clearly separate them from older age group patients. This study serves to emphasise that in order to prevent the development of myocardial infarction special attempts sould be made to prevent cigarette smoking in those whose fathers have died of a myocardial infarction or have symptoms of ischaemic heart disease.