Table 1.

Inclusion/exclusion criteria for normal blood pressure participants

Inclusion criteria	Exclusion criteria
Local resident for more than 5 years Age 35–70 years Han nationality Independent individuals Those from the same community where patients with primary hypertension were selected SBP <140 mm Hg and DBP <90 mm Hg, without antihypertensive treatment Willingness to volunteer to participate in the trial and sign the informed consent form	Use of any antihypertensive drug in the previous 24 hours Clinical diagnosis of cardiovascular disease, kidney disease, liver disease or malignant tumour Pregnant women Self-adherence to a low-sodium diet Inability or unwillingness to participate in the study or sign the informed consent form

DBP, diastolic blood pressure; SBP, systolic blood pressure.