Association between white blood cell count and carotid arteriosclerosis in Japanese smokers

Recent studies have shown the relationship between general inflammatory markers and ischemic heart and cerebrovascular diseases. Here we have investigated the potential association between the circulating white blood cell count and carotid arteriosclerosis in apparently healthy individuals. Between 1994 and 1998, 3455 subjects who had undergone general health screening tests including carotid ultrasonography were enrolled in this study. The intertertile cutoff points for the white blood cell count were 5.1×103 and 6.4×103 μL−1 in the male subjects and 4.6×103 and 5.7×103 μL−1 in the female subjects. The prevalence of carotid plaque in the first (lowest), the second, and the third tertiles was 19, 28, and 28% in the male subjects, respectively (P<0.0001), and 10, 15, and 14% in the female subjects, respectively (n.s.). The multivariate analysis showed that the male subjects in the second and third tertiles had increased risk for carotid plaque with odds ratios of 1.54 (95% CI 1.18–2.01) and 1.47 (95% CI 1.11–1.95), respectively, compared to those in the first tertile. When male subjects were subdivided according to their smoking status, the association between white blood cell count and carotid plaque was significant in those who smoked, but not in those who had never smoked. These data suggested the possible association between the circulating white blood cell count and formation of carotid plaque in male smokers, but not in male never smokers or in females, in an apparently healthy Japanese population.