Differential leucocyte count and the risk of future coronary artery disease in healthy men and women: the EPIC-Norfolk Prospective Population Study

Background: We examined the relationship between granulocyte, lymphocyte and monocyte counts and risk of coronary heart disease (CHD) and cardiovascular disease (CVD) in men and women. There is paucity of data on the differential leucocyte count and its relationship with the risk of CHD and CVD. Methods: This prospective study comprised 7073 men and 9035 women who were 45-79 years of age and were residents of Norfolk. United Kingdom. Results: During an average of 8 years of follow-up we identified 857 incident CHD events and 2581 CVD incident events. Increased total leucocyte count was associated with increased risk for both CHD and CVD. The highest quartile of granulocyte count was associated with increased risk when compared to lowest quartile for CHD (men HR 1.70 95% CI: 1.30-2.21; women HR 1.24 95% CI: 0.91-1.69) and for CVD (men HR 1.46 95% CI: 1.24-1.71; women HR 1.20 95% CI: 1.02-1.42). The association remained unchanged when the analyses were restricted to nonsmokers and when risk was assessed for every 1000 cells L-1 increase in cell count. In multivariable models, despite adjusting for C-reactive protein (CRP), the granulocyte count remained an independent predictor of CHD and CVD risk, especially amongst men. Lymphocyte or monocyte counts were not significantly associated with increased risk. In all analyses, additionally adjusting for CRP did not affect the results materially. Conclusions: In conclusion, we found that the higher risk for CHD and CVD associated with increased total leucocyte count seems to be accounted for by the increased granulocyte count.