Table 2.

Covariates recorded in the current study.

Covariates	Categories
Age	1 = 18–44 years, 2 = 45–60 years, 3=>60 years
Education	1 = primary school and below, 2 = middle school, 3 = high school or equivalent, 4 = 3-year college and above
Duration of hypertension since diagnosis	Years
Occupation	1 = employed, 2 = unemployed
Family history of hypertension	1 = yes, 2 = no, 3 = unknown
Registration	1 = locals, 2 = migrants, which refers to internal migrants who do change their official household registration to their new place of residence.