Behavioural characteristics in patients with myocardial infarction: a case-control study

Over the past 10-20 years, evidence has accumulated suggesting that it is not just biological risk factors that are important for the development of coronary heart disease. The present study is one of a series of case-control studies in which a wide range of psychosocial factors have been analysed in the same population to obtain information on their relationship with myocardial infarction, as well as of the interaction between psychosocial and biomedical variables.

The relationship between behavioural factors and non-fatal myocardial infarction was studied by comparing consecutively admitted male (n = 288) and female (n = 55) patients with a population sample of 283 men and 129 women. All participants were under 65 years of age. The behavioural variables (type-A behaviour, health locus of control, sleep problems and alcohol consumption) were investigated by means of a self-administered questionnaire.

No significant differences emerged between patients with myocardial infarction and controls in terms of their type-A behaviour pattern. After controlling for traditional risk factors (smoking, hypertension, serum cholesterol level and diabetes), men with myocardial infarction reported a significantly stronger external health locus of control (i.e. a weak belief in their capacity to control their health) compared with their controls, as well as more problems with sleep and a lower alcohol consumption; women with myocardial infarction reported significantly more problems with sleep than their controls.

The importance of health locus of control, sleep problems and alcohol consumption is amplified by the fact that they are related to myocardial infarction independently of conventional biomedical risk factors. These behavioural factors should be studied further in prospective investigations.