Table 1 Descriptive statistics in HRS, CHARLS, SHARE, ELSA, and MHAS

Age

66.24 ± 10.28

62.32 ± 8.37

68.00 ± 9.75

67.65 ± 9.25

65.15 ± 9.42

Gender

Male

25,928(41.20)

17,418(47.25)

54,307(43.47)

12,325(45.40)

14,404(42.03)

Female

37,004(58.80)

19,448(52.75)

70,619(56.53)

14,821(54.60)

19,869(57.97)

Educational levels

Less than high school

10,188(16.19)

32,786(88.93)

48,207(38.59)

6677(24.60)

28,786(83.99)

High school

37,270(59.22)

3554(9.64)

48,189(38.57)

14,546(53.58)

1209(3.53)

University and above

15,474(24.59)

526(1.43)

28,530(22.84)

5923(21.82)

4278(12.48)

Work for payment

No

36,663(58.26)

13,613(36.93)

86,417(69.17)

18,435(67.91)

20,782(60.64)

Yes

26,269(41.74)

23,253(63.07)

38,509(30.83)

8711(32.09)

13,491(39.36)

Married or partnered

No

23,641(37.57)

5321(14.43)

32,501(26.02)

7512(27.67)

10,811(31.54)

Yes

39,291(62.43)

31,545(85.57)

92,425(73.98)

19,634(72.33)

23,462(68.46)

Household wealth

Low

23,894(37.97)

12,108(32.84)

43,994(35.22)

8190(30.17)

13,290(38.78)

Middle

17,825(28.32)

12,711(34.48)

40,258(32.23)

9101(33.53)

9381(27.37)

High

21,213(33.71)

12,047(32.68)

40,674(32.56)

9855(36.30)

11,602(33.85)

Smoking

No

54,062(85.91)

26,640(72.26)

104,254(83.45)

24,401(89.89)

30,151(87.97)

Yes

8870(14.09)

10,226(27.74)

20,672(16.55)

2745(10.11)

4122(12.03)

Drinking

No

26,614(42.29)

20,406(55.35)

64,163(51.36)

3640(13.41)

25,708(75.01)

Yes

36,318(57.71)

16,460(44.65)

60,763(48.64)

23,506(86.59)

8565(24.99)

Co-residence with children

No

58,389(92.78)

19,998(54.25)

101,421(81.18)

21,441(78.98)

10,102(29.48)

Yes

4543(7.22)

16,868(45.75)

23,505(18.82)

5705(21.02)

24,171(70.52)

Internet use

No

26,423(41.99)

34,815(94.44)

59,699(47.79)

7506(27.65)

20,779(60.63)

Yes

36,509(58.01)

2051(5.56)

65,227(52.21)

19,640(72.35)

13,494(39.37)

Frailty index

18.62(10.86–30.06)

17.16(11.12–26.58)

13.97(8.28–23.62)

12.82(7.22–22.24)

16.18(9.23–27.13)

Frailty status

Non-frailty

41,284(65.60)

26,407(71.63)

96,850(77.53)

21,522(79.28)

24,593(71.76)

Frailty

21,648(34.40)

10,459(28.37)

28,076(22.47)

5624(20.72)

9680(28.24)