Table 1  A statistical description of respondents’ characteristics (n = 5,295)

Outcome

Cognitive ability

Mean (SD)

26.17 (5.01)

Social support

Financial support (logarithm)

Mean (SD)

5.55 (3.59)

Emotional support

Mean (SD)

1.58 (1.32)

Social economic status (SES)

Schooling

Literate, N (%)

2989 (56.45%)

Illiterate, N (%)

2306 (43.55%)

Occupation

White collar, N (%)

629 (11.88%)

Non-white collar, N (%)

4666 (88.12%)

Economic independence

Yes, N (%)

1411 (26.65%)

No, N (%)

3884 (73.35%)

Residence

Urban, N (%)

2933 (55.39%)

Rural, N (%)

2362 (44.61%)

SES score, 0–4

Mean (SD)

1.50 (1.19)

Control variables

Social demographic

Age, years

Mean age at baseline, mean (SD)

82.49 (10.98)

65–74, N (%)

1508 (28.48%)

75–84, N (%)

1605 (30.31%)

85–94, N (%)

1294 (24.44%)

>=95, N (%)

888 (16.77%)

Sex

Male, N (%)

2442 (46.12%)

Female, N (%)

2853 (53.88%)

Marital status

Others, N (%)

2772 (52.35%)

Married and with spouse, N (%)

2523 (47.65%)

Living region

West, N (%)

1166 (22.02%)

Middle, N (%)

1559 (29.44%)

East, N (%)

2570 (48.54%)

Hukou

Urban, N (%)

1417 (26.76%)

Rural, N (%)

3878 (73.24%)

Health insurance

Yes, N (%)

4700 (88.76%)

No, N (%)

595 (11.24%)

Lifestyle

Diet diversity

Not diverse, N (%)

2764 (52.20%)

Diverse, N (%)

2531 (47.80%)

Smoking status

Ever, N (%)

893 (16.86%)

Never, N (%)

4402 (83.14%)

Drinking status

Ever, N (%)

874 (16.51%)

Never, N (%)

4421 (83.49%)

BMI

Underweight, overweight or obese, N (%)

2389 (45.12%)

Normal, N (%)

2906 (54.88%)

Exercise

No, N (%)

3402 (64.25%)

Yes, N (%)

1893 (35.75%)

Health conditions

ADL

Mean (SD)

0.33 (0.99)

Depression

Mean (SD)

9.17 (4.13)

Hypertension

No, N (%)

2982 (56.32%)

Yes, N (%)

2313 (43.68%)

Diabetes

No, N (%)

4754 (89.78%)

Yes, N (%)

541 (10.22%)

Stroke

No, N (%)

4756 (89.82%)

Yes, N (%)

539 (10.18%)