The Tromso heart study: risk factors for coronary heart disease related to the occurrence of myocardial infarction in first degree relatives.

In a population survey for risk factors associated with coronary heart disease among 6595 men aged 20-49 years of age, a family history of myocardial infarction (MI) was obtained by interview. A high degree of concurrence (78%) was found between the reported and confirmed diagnoses. Subjects who had evidence of a previous MI had a significantly higher frequency of first degree relatives with MI compared to healthy men of the same age. In subjects with first degree relatives of either sex suffering from MI before age 50, the mean serum cholesterol concentration was found to be slightly but not significantly elevated. However, when the relatives were females below age 50, the subjects had significantly elevated mean systolic blood pressure (0.05 greater than p greater than 0.01). The differences between subjects with a positive and negative family history of MI were surprisingly small. Correspondingly, there was no difference in the frequency of MI relatives in subjects belonging to the upper and lower quintiles of the serum cholesterol and blood pressure distribution. The slight elevations in serum cholesterol and blood pressure contribute only to a very small extent to the increased risk to subjects with a positive family history.