This study intends to establish the normal reference values of carotid artery intima-media thickness and vascular elasticity of Chinese adults based on ultrasound radio frequency technology through a multi-center large-sample study, which provides important information for the risk prediction and prognosis evaluation of Chinese adults' cardiovascular disease.

After being informed about the study, all participants giving written informed consent will undergo a one-time examination of vascular ultrasound, including general characteristics and the target ultrasound parameters.

To detect the smallest difference between adjacent age groups within the age range 18-79 (6 groups, α = 0.05, β = 0.20, Statistical Power = 0.80). Given the influence of multiple centers, the minimum sample size is 1800, the optimal sample size is 3500. The male to female ratio is 1:1.

Quality Control including the pre-study training and data monitoring during the study.

Inclusion Criteria:

• Aged 18-79
• The blood pressure is normal: systolic blood pressure <140 mmHg, and diastolic blood pressure <90 mmHg
• The physical examination and electrocardiogram are normal

Exclusion Criteria:

• Subjects with carotid intima-media thickness ≥ 1.0 mm should be excluded;
• Subjects with previous cardiovascular disease history and medication history should be excluded. The main diseases include coronary heart disease, congenital heart disease, heart failure, hypertension, stroke, hyperlipidemia, diabetes, aortic arteritis, etc.;
• Subjects with past medical history and medication history of endocrine, rheumatism, chronic respiratory disease, liver and kidney disease should be excluded;
• Obese subjects (BMI ≥ 28 kg/m2), professional athletes, pregnant and lactating women should be excluded;
• Alcohol or drug addicts and smokers who have not quit smoking should be excluded.

Healthy Han Chinese adults

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