Table 3.

Linear regression parameter estimation and testing

Variable	Parameter Estimate	Pr > t
9 ~ (X1)	−0.041	0.469
18 ~ (X2)	0.018	0.349
31 ~ (X3)	0.036	0.492
41 ~ (X4)	−0.017	0.737
51 ~ (X5)	0.035	0.493
Civil servant/enterprise and public institution/technician (X6)	0.244	0.000
Worker/migrant labourer/farmer (X7)	0.189	0.000
Retired/student (X8)	0.080	0.136
Unemployed/self-employed (X9)	0.065	0.285
Elementary school(X10)	0.094	0.535
Junior high school (X11)	0.233	0.120
Senior high school (X12)	0.114	0.443
Bachelor’s (X13)	0.153	0.299
Urban (X14)	0.100	0.272
Rural(X15)	0.189	0.038
Sex	excluded from the model
Hypertension	excluded from the model
Diabetes	excluded from the model