Table 1 Sociodemographic characteristics of the participants (N = 4872)

Age

27(2–57)

 20–29

4294(88.1)

 < 0.001

 30–39

476(9.8)

50(20–75)

 40–49

102(2.1)

24(0–51)

Permanent Residence

 Urban

3854(79.1)

30(2–60)

0.816

 Rural

1018(20.9)

29(5–58)

Education

 Junior high school and below

88(1.8)

49(18–73.3)

 < 0.001

 Senior high school

886(18.2)

23(1–56)

 Bachelor

3559(73.0)

30(3–59)

 Master and above

339(7.0)

42(5–71)

Marital status

 Unmarried

4378(89.9)

25(2–53)

 < 0.001

 Married

494(10.1)

61(35.8–83)

Number of properties

 0

856(17.6)

25(1.3–52.8)

 < 0.001

 1

2547(52.2)

35(5–60)

 2

1028(21.1)

26.5(2–26.5)

 3

441(9.1)

22(0–53)

Housing area (M²)

  < 90

1438(29.5)

26(1–54)

 < 0.001

 90–150

2934(60.2)

33(5–60)

  ≥ 150

500(10.3)

21.5(0–55.8)

Family per capita monthly income (CNY)

  ≤ 3000

1522(31.2)

22(1–50)

 < 0.001

 3001–6000

2012(41.3)

34(5–60)

 6001–12000

925(19.0)

39(5–61)

  ≥ 12,000

413(8.5)

25(2–62)

Debt

 No

 Yes

1744(35.8)

3128(64.2)

29(2–59)

31.5(4–60)

0.124