Table 1 Characteristics of 16,786 participants by depressive symptoms group

Age (years), mean (SD)

65.1 (7.3)

67.2 (7.0)

< 0.001

Sex, women, %

11,585 (72.9)

660 (74.2)

0.37

BMI (kg/m²), mean (SD)

23.8 (3.5)

23.8 (3.9)

0.95

Education level, %

 Primary or below

6038 (38.0)

478 (53.8)

 Middle school

8371 (52.6)

369 (41.5)

< 0.001

 College and above

1488 (9.4)

42 (4.7)

Occupation, %

 Manual

7298 (45.9)

561 (63.1)

 Non-manual

5496 (34.6)

218 (24.5)

< 0.001

 Other

3103 (19.5)

110 (12.4)

Family income (Yuan/ year), %

 <  10,000

1863 (11.7)

172 (19.3)

 10,000–19,999

2384 (15.0)

268 (30.1)

< 0.001

 ≥20,000

11,650 (73.3)

449 (50.6)

Physical activity, %

 No

118 (0.7)

19 (2.1)

 Low level (walking)

7603 (47.8)

517 (58.2)

< 0.001

 Medium level

7606 (47.8)

334 (37.6)

 High level

570 (3.6)

19 (2.1)

Smoking status, %

 Never

12,589 (79.2)

698 (78.5)

 Former

1923 (12.1)

124 (13.9)

0.15

 Current

1385 (8.7)

67 (7.5)

Alcohol consumption, %

 Never

7528 (47.4)

398 (44.7)

 Former

42 (0.3)

9 (1.0)

< 0.001

 Current

8327 (52.4)

482 (54.3)

Support from family members, % positive

15,709 (98.8)

850 (95.6)

< 0.001

Contacts with relatives and friends, %

 Not at all

351 (2.2)

61 (6.9)

 <once/month

2410 (15.2)

193 (21.7)

 ≥once/month

6044 (38.0)

280 (31.5)

< 0.001

 ≥once/week

5472 (34.4)

256 (28.9)

 Almost daily

1620 (10.2)

99 (11.1)

Presence of chronic diseases, %

 Yes

9595 (60.4)

614 (69.0)

< 0.001

Self-rated health, % good

2759 (17.4)

122 (13.7)

0.005

Daytime napping, % nappers

9508 (59.8)

579 (65.1)

< 0.001

Global sleep quality, %

 Poor (PSQI ≥6)

4785 (30.1)

571 (64.2)

< 0.001