Objective: To explore the association between blood pressure level and incidence of carotid arterial plaque in middle-aged and elderly people.
Methods: A total of 5852 individuals were randomly stratified from the 101 510 health examination survey participants in Tangshan Kailuan Company community during 2006-2007. A total of 5440 people (age above 40 years old, free of stroke, TIA and myocardial infarction) were enrolled in the final analysis. A questionnaire survey, blood biochemical analysis and carotid artery ultrasound examination were finished by trained medical staff. Sixteen individuals without carotid artery plaques information and 35 individuals without blood pressure information were excluded. Finally, a total of 5389 participants [3235 male, mean age: (54.7 ± 11.8) years] were analyzed. According to 2010 Chinese guideline to prevention and treatment of hypertension and blood pressure level classification, participants were divided into normotensive group (n = 1377), high normal blood pressure group (n = 1971) and hypertensive group (n = 2041). Multivariate logistic regression analysis was used to determine the risk factors of the carotid artery plaques.
Results: Age, male gender, BMI, IMT, TG, FBG, smoking and alcohol drinking rate were significantly higher in high normal blood pressure group than in normotensive group (all P < 0.05), LDL-C, HDL-C, hs-CRP and TC were similar between these two groups. Incidence of carotid artery plaques in normotensive, high normal blood pressure and hypertensive groups was 24.8%, 37.4%, 60.2% respectively. The risk of carotid artery plaques was increased to 38% and 163% in high normal and hypertensive groups compared to normotensive group, the OR ratio was 1.38 (95%CI: 1.15-1.66) and 2.63 (95%CI: 2.18-3.18), respectively. After adjusting gender, age, smoking, alcohol consumption, TG, TC, HDL-C, FBG, hs-CRP and BMI, the risk of developing carotid artery plague was increased in proportion to increasing blood pressure and the OR value was 1.24 (95%CI:1.01-1.52) , 1.69 (95%CI:1.34-2.15) and 2.66 (95%CI:2.20-3.21) in high normal group I [SBP/DBP 121-129/80-84 mm Hg(1 mm Hg = 0.133 kPa)] and high normal group II (SBP/DBP 130-139/85-89 mm Hg) and hypertensive group, respectively.
Conclusions: The cardiovascular risk factors and prevalence of carotid artery plague increase in proportion to blood pressure level in this cohort. The detection rate of carotid artery plague is already significantly increased in individuals with high normal blood pressure.