Table 1 The list of explanatory variables for analysis

Predisposing

Demography

Sex

Female (Reference group); Male

Age (years)

15–19 (Reference group); 20–29; 30–39; 40–49; ≥50

Social structure

Marital status

Unmarried (Including divorced/widowed, reference group); Married (Including first marriage, remarriage, cohabitation)

Education attainment

Primary school or below (Reference group); Middle school; High school or secondary; University or college and above

Enabling

Individual/family resources

Household monthly income (CNY)

< 4,000 (Reference group); 4,000–5,499; 5,500-7,499; 7,500-9,999; ≥10,000

Average weekly working time (hours)

≤ 40 (Reference group); 41–69; ≥70

Region resources

Survey region

East (Reference group); Central; West; Northeast

Need

Had health record

No (Reference group); Yes

Contracted family doctor

No (Reference group); Yes

Self-evaluation general health status

Good (Reference group); Other (Including fair; unwell)

Migration characteristics

Length of migration (years)

≤ 3 (Reference group); 4–6; 7–9; ≥10

Range of migration

Inter-provincial (Reference group); Intra-provincial; Inter-country within the city