title: White blood cell count, especially neutrophil count, as a predictor of hypertension in a Japanese population.
abstract: Although several studies have shown that high WBC count is a risk factor for hypertension, the relationship between WBC count and the incidence of hypertension in Japanese is poorly understood, as are the effects of WBC components on that relationship. Our objective was to verify in a Japanese population whether WBC or differential WBC count predicts hypertension incidence. A total of 9,383 initially hypertension-free subjects (3,356 men and 6,027 women), whose WBC counts were within the normal range (3,000 to < 10,000 cells/mm3), were followed from 1965 to 2004. During this 40-year follow-up, 4,606 subjects developed hypertension. After adjusting for conventional risk factors, including smoking status, we found that elevated WBC count was associated with hypertension incidence in a Cox regression model with both fixed and time-varying covariates for women. For men, elevated WBC count was a significant risk factor for hypertension only in the time-varying Cox-regression covariate. We also observed a significant association between increased neutrophil count and hypertension incidence among women. In a fully adjusted model, the relative risks of hypertension incidence, from the lowest to the highest quartiles of neutrophil count, were 1.00, 1.18, 1.28, and 1.22 in women (p for trend < 0.001). In conclusion, elevated WBC count predicted an increased incidence of hypertension in Japanese, especially among females. Moreover, neutrophils were the major WBC component contributing to the increased risk.
authors.affiliation: Department of Clinical Studies, Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Tatsukawa
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Hsu
authors.forename: Michiko
authors.initials: M
authors.lastname: Yamada
authors.forename: John B
authors.initials: JB
authors.lastname: Cologne
authors.forename: Gen
authors.initials: G
authors.lastname: Suzuki
authors.forename: Hideya
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Kiminori
authors.initials: K
authors.lastname: Yamane
authors.forename: Masazumi
authors.initials: M
authors.lastname: Akahoshi
authors.forename: Saeko
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Nobuoki
authors.initials: N
authors.lastname: Kohno
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000209:etiology*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000502:physiology*; D012044:Regression Analysis; D012307:Risk Factors