Physiological markers of smoking and their relation to coronary heart disease. The Lipid Research Clinics Coronary Primary Prevention Trial.

Several physiological variables which have previously been found to be associated with extent of cigarette smoking were investigated in a population selected to be free of existing coronary heart disease yet having high circulating cholesterol levels. Of these variables, white blood cell count had the strongest association with the extent of smoking. The addition of hematocrit and heart rate to white blood cell count strengthened the association. Given these three variables, however, other physiological variables had a minor effect on the association. Finally, the combination of these three physiological variables was more strongly predictive of subsequent coronary heart disease than was self-reported smoking level.