[Relationship between leukocyte count and risk of hypertension]

To observe the association between the leukocyte count and blood pressure value and hypertension risk in a Chinese community-based population.

A total of 4 188 participants who took part in the baseline examination in 1992 and the follow-up survey in 2007 from the Chinese Multi-Provincial Cohort Study were included in this study. The relationship of leukocyte and blood pressure value and hypertension risk were evaluated by cross-sectional analyses.The prospective association between baseline leukocyte count and blood pressure changes and risk of hypertension were analyzed in 2 954 normotensive individuals at baseline examination.The associations between leukocyte count and blood pressure was evaluated with Spearman's rank correlation analyses and linear regression models,and the associations between leukocyte count and risk of hypertension was evaluated with logistic regression models.

(1) The cross-sectional study results showed that the correlation coefficient of leukocyte count and systolic blood pressure and diastolic blood pressure was 0.208 and 0.154 (both P < 0.001), respectively.Multiple linear regression analyses showed that every 1×10(9)/L increment in leukocyte count was associated with 1.41 mmHg (1 mmHg = 0.133 kPa) systolic blood pressure increase (95% CI: 1.20-1.63 mmHg, P < 0.001) and 0.63 mmHg diastolic blood pressure increase (95% CI: 0.51-0.76 mmHg, P < 0.001). Multivariable logistic regression analyses showed that every 1×10(9)/L increment in leukocyte count was associated with a 15% increased risk of hypertension (OR: 1.15, 95% CI: 1.12-1.19, P < 0.001). (2) During 15 years of follow-up, 47.2% (1 394/2 954) normotensive individuals progressed to hypertension. Spearman's rank correlation analyses showed that, the correlation coefficient of leukocyte count and systolic blood pressure change and diastolic blood pressure change was 0.062 (P = 0.003) and 0.102 (P < 0.001), respectively.Multiple linear regression analyses showed that every 1×10(9)/L increment in baseline leukocyte count was associated with 1.03 mmHg systolic blood pressure increase (95% CI: 0.74-1.32 mmHg, P < 0.001) and 0.64 mmHg diastolic blood pressure increase (95% CI: 0.48-0.80 mmHg, P < 0.001). Multivariable logistic regression analyses showed that every 1×10(9)/L increment in leukocyte count was associated with a 9% increased risk of incident hypertension (OR: 1.09, 95% CI: 1.06-1.13, P < 0.001).

Elevated leukocyte count is associated with increased blood pressure value and hypertension among Chinese community-based population, suggesting that inflammation may participate in the pathogenesis of hypertension.