Total and differential white blood cell counts predict eight-year incident coronary heart disease in elderly Japanese-American men: The Honolulu Heart Program

Background: Previous studies have reported an association between total and differential white blood cell (WBC) counts and incident coronary heart disease (CHD), but data from elderly populations are scarce. The purpose of this study was to examine the association between total and differential WBC counts and incident CHD in an elderly Japanese-American population. Methods: Total and differential WBC counts were examined at a baseline examination from 1991 to 1993 in the Honolulu Heart Program. Subjects were Japanese-American men aged 71-93 years free of CHD at baseline (N = 2879), who were divided into quartiles of total and differential WBC counts for analysis, and were followed for incident CHD for 8 years. Results: During the follow up period, 279 men developed CHD. Hazard ratio for incident CHD for each quartile of total and differential WBC counts were obtained by Cox regression using the lowest quartile as the reference group. After full adjustment including age, cardiovascular risk factors, chronic diseases and medication use, the hazard ratios in the highest quartiles of total WBC, granulocyte and neutrophil counts were 1.75 (95% confidence interval [CI], 1.18-2.62; P = 0.006), 1.66 (95%CI, 1.11-2.48; P = 0.01), and 1.57 (95%CI, 1.06-2.34; P = 0.03), respectively. No significant associations were found between lymphocyte or monocyte counts and incident CHD. Conclusions: Higher total WBC, granulocyte and neutrophil counts were associated with higher risk of incident CHD in a population of elderly Japanese-American men. Further studies are needed to establish cut-points and treatment options with anti-inflammatory medications.