Leukocyte count is an independent predictor for risk of acute myocardial infarction in middle-aged Japanese men

Background Leukocyte count is recognized as an inflammatory marker and a predictor of cardiovascular events. However, it is uncertain whether the contribution of leukocyte count to the risk of cardiovascular disease is independent of smoking. Methods The subjects were 4492 male employees aged 40–59 years who worked for nine companies in Osaka. Results After 9-year follow-up, 40 acute myocardial infarction and 26 ischemic stroke events occurred. Age-adjusted relative risk of acute myocardial infarction in the highest versus lowest quartiles of leukocyte count was 6.0 (95% CI, 1.8–20.5, Pfor trend <0.001) and the multivariable relative risk adjusted for smoking and other conventional cardiovascular risk factors was 3.7 (1.0–13.4, P for trend = 0.01). The association between leukocyte count and the risk of acute myocardial infarction was also observed among both current smokers and nonsmokers. The positive association between leukocyte count and the risk of ischemic stroke was weak and did not reach statistical significance. Conclusions Leukocyte count is a predictor of acute myocardial infarction among Japanese middle-aged men, both in smokers and nonsmokers.