Smoking, coronary artery occlusion, and nonfatal myocardial infarction.

The association of smoking with a history of myocardial infarction (MI) was studied in 3,997 men who had coronary arteriography. The patients were subdivided into groups based on coronary occlusion (minimal, moderate, or severe) and plasma cholesterol level (low, moderate, or high). For men older than 50 years, smoking was significantly associated with MI in each occlusion group. For men younger that 50 years, the association was significant for men with moderate or severe occlusion. In the presence of higher cholesterol levels there was a stronger association of smoking with MI, but weaker association association of smoking with coronary occlusion. These results suggest that the association of smoking with MI does not depend primarily on the atherogenic effect of smoking. The association seems to be enhanced by high levels of coronary occlusion and cholesterol.