White blood cell count and incidence of hypertension in the general Japanese population: ISSA-CKD study.

Shintaro Ishida,Koji Takahashi,Chikara Yoshimura,Miki Kawazoe,Tetsuhiko Yasuno,Hitoshi Nakashima,Hisatomi Arima,Kosuke Masutani,Toshiki Maeda,Shunsuke Funakoshi,Seiji Kondo,Kenji Ito,Atsushi Satoh,Kazuhiro Tada,Tatsuo Shimosawa

doi:10.1371/journal.pone.0246304

Abstract

This study aimed to clarify the relationship between the white blood cell (WBC) count and hypertension in the general Japanese population. We conducted a population-based retrospective cohort study using annual health check-up data of residents of Iki City, Nagasaki Prefecture, Japan. A total of 2935 participants without hypertension at baseline were included in the present analysis. WBC counts were classified as tertile 1 (<4700/μL), tertile 2 (4700-5999/μL), and tertile 3 (≥6000/μL). The outcome was incident hypertension (blood pressure ≥140 mmHg). Multivariable-adjusted hazard ratios and 95% confidence intervals (95% CIs) were estimated using the Cox proportional hazards model. During an average follow-up of 4.5 years, 908 participants developed hypertension. The incidence (per 100 person-years) of hypertension increased with an elevation in the WBC count (6.3 in tertile 1, 7.0 in tertile 2, and 7.4 in tertile 3). This association was significant, even after adjustment for other risk factors, including age, sex, current smoking habits, current alcohol intake, exercise habits, obesity, elevated blood pressure, diabetes mellitus, and dyslipidemia. The hazard ratios were 1.07 for tertile 2 (95% CI 0.90-1.26) and 1.27 for tertile 3 (95% CI 1.06-1.51) compared with the reference group of tertile 1 (p = 0.009). The WBC count was associated with future development of hypertension in the general Japanese population.

Highlights

Cardiovascular disease is a leading cause of premature death in Japan, as well as in other countries in the world [1, 2]
The white blood cell (WBC) count was associated with future development of hypertension in the general Japanese population
The incidence rate of hypertension increased with elevation of the WBC count (6.3% per 100 person-years in tertile 1, 7.0% in tertile 2, and 7.4% in tertile 3)

Summary

Introduction

Cardiovascular disease is a leading cause of premature death in Japan, as well as in other countries in the world [1, 2]. Effective prevention of hypertension and subsequent cardiovascular disease requires strategies that are based on current knowledge of risk factors in Japan. Chronic inflammation is a risk factor of hypertension [1, 2, 4,5,6,7,8,9]. Current evidence of this risk factor is mainly based on the association between high-sensitivity C-reactive protein and hypertension, and is mainly derived from Western populations [10,11,12,13]. Whether the white blood cell (WBC) count can predict development of hypertension in the Asian population is unclear [14]. This study aimed to clarify the relationship between the WBC count and hypertension in the general Japanese population

Objectives

Methods

Results

Conclusion