Table 1.

Coding of independent variables.

Variables	Assignment
Gender	Female=0; male=1
Age (years)	15-45=1; 46-60=2; >60=3
Marital statusa	Single=0; married=1
Area	Rural=0; urban=1
Education level	Junior high school or below=1; senior high school =2; 3-year college=3; bachelor’s or above=4
Annual household income per capita (RMB ¥b)	<10k=1; 10k-30k=2; 30k-50k=3; >50k=4
Employmentc	Unemployed=0; employed=1
Types of primary health insurance	Urban employee basic medical insurance=1; urban-rural resident basic medical insurance=2; othersd=3
Having commercial health insurance	No=0; yes=1
Having at least 1 chronic disease	No=0; yes=1
Reported illness in the past 12 months	No=0; yes=1

^aMarital status was divided into 2 categories: single (unmarried, divorced, or widowed) and married (married).

^bRMB ¥1=US $0.15641.

^cEmployment was recoded as 2 groups: unemployed (unemployed, students, and retired) and employed (employed).

^dOthers included no primary health insurance and health insurance outside mainland China.