Association of passive smoking with increased coronary heart disease risk is not explained by elevation of leucocyte count

The increased risk of coronary heart disease in cigarette smokers may be due at least partly to an elevation of the leucocyte count Chronic passive smoking has also been found to be associated with an increased risk of coronary heart disease, but its effect on the leucocyte count has not been reported. In this study 250 male factory employees aged 20-64 years were interviewed on smoking behaviour and exposure to environmental tobacco smoke, and blood counts were determined. Urinary cotinine was measure by radio-immunoassay and corrected for urinary creatinine concentrations. Mean leucocyte count was significantly higher among smokers compared with non-smokers (8,666 compared to 6, 900; p<0.001). On the basis of smoking history, passive smokers had leucocyte counts similar to non-smokers. These findings were confirmed when leucocyte counts were compared with urine cotinine to creatinine ratios. The association of haematocrlt and haemoglobin with smoking was similar to that of leucocyte count These findings suggest that any association of passive smoking with coronary heart disease is not through an elevation of leucocyte count.