Association of hematocrit and pre-hypertension among Chinese adults: the CRC study.

Elevated blood pressure is regarded as an independent risk factor for cardiovascular diseases and diabetes. We examined the relation between hematocrit and pre-hypertension as well as the effect of sex, obesity, fasting glucose, and lipids in Chinese adults. The study samples were from a community-based health examination survey in China and included a total of 2,3691 patients with blood pressure in normal range. The odds ratios [ORs, 95 % confidence interval (CI)] of pre-hypertension across increasing quartiles of hematocrit were 1.000, 1.176 (1.050-1.318), 1.213 (1.081-1.363), and 1.364 (1.209-1.540) (P for trend < 0.001), when adjusted for age, sex, body mass index, glutamic-pyruvic transaminase, glutamic-oxalocetie transaminase, serum uric acid, glucose, and lipids. Associations were significant in both men and women, but not in individuals older than 60 years. In addition, low-density lipoprotein cholesterol significantly interacted with hematocrit (P for interaction <0.024). The associations were more evident in patients with low (P < 0.001) and median LDL-C levels (P < 0.013) than those with high glucose levels. Hematocrit was associated with pre-hypertension, and was independent of metabolic risk factors. These associations were not significant in older individuals and low-density lipoprotein cholesterol may modify these associations.