Table 1 Baseline characteristics of participants by childhood friendship status
Characteristics | Total (n = 4,350) | Childhood friendship, No. (%) | p value | ||
|---|---|---|---|---|---|
Poor (n = 692) | Fair (n = 1,540) | Good (n = 2,118) | |||
Sociodemographic | |||||
Age, mean (SD) | 56.29 (7.80) | 58.37 (7.92) | 56.71 (7.69) | 55.31 (7.68) |  < 0.001 |
Female | 1919 (44.1) | 274 (39.6) | 651 (42.3) | 994 (46.9) | 0.001 |
Rural residence | 2501 (57.5) | 480 (69.4) | 922 (59.9) | 1099 (51.9) |  < 0.001 |
Married/partnered | 4041 (92.9) | 630 (91.0) | 1437 (93.3) | 1974 (93.2) | 0.116 |
Educational level | |||||
 Illiterate | 277 (6.4) | 73 (10.5) | 110 (7.1) | 94 (4.4) |  < 0.001 |
 Some primary school | 657 (15.1) | 172 (24.9) | 250 (16.2) | 235 (11.1) |  |
 Finished primary school | 1160 (26.7) | 207 (29.9) | 456 (29.6) | 497 (23.5) |  |
 Higher than primary school | 2256 (51.9) | 240 (34.7) | 724 (47.0) | 1292 (61.0) |  |
Household expenditure per capita | |||||
 Low | 805 (21.1) | 158 (25.6) | 302 (22.7) | 345 (18.5) |  < 0.001 |
 Medium | 1943 (51.0) | 324 (52.6) | 711 (53.5) | 908 (48.7) |  |
 High | 1060 (27.8) | 134 (21.8) | 316 (23.8) | 610 (32.7) |  |
Childhood conditions | |||||
Childhood family financial situation | |||||
 Worse off | 1602 (36.9) | 327 (47.3) | 595 (38.7) | 680 (32.1) |  < 0.001 |
 About average | 2311 (53.2) | 327 (47.3) | 823 (53.5) | 1161 (54.8) |  |
 Better off | 434 (10.0) | 37 (5.4) | 121 (7.9) | 276 (13.0) |  |
Childhood hukou (non-agricultural) | 519 (12.0) | 46 (6.7) | 140 (9.1) | 333 (15.8) |  < 0.001 |
Childhood health | |||||
 Less healthy | 494 (11.4) | 108 (15.6) | 174 (11.3) | 212 (10.0) |  < 0.001 |
 About average | 2164 (49.8) | 357 (51.7) | 810 (52.7) | 997 (47.1) |  |
 Healthier | 1689 (38.9) | 226 (32.7) | 554 (36.0) | 909 (42.9) |  |
Adverse childhood experiences | |||||
 0 | 1240 (28.5) | 156 (22.5) | 403 (26.2) | 681 (32.2) |  < 0.001 |
 1 | 1525 (35.1) | 232 (33.5) | 546 (35.5) | 747 (35.3) |  |
 2 | 957 (22.0) | 178 (25.7) | 360 (23.4) | 419 (19.8) |  |
  ≥ 3 | 628 (14.4) | 126 (18.2) | 231 (15.0) | 271 (12.8) |  |
Cognitive function | |||||
Total cognitive score, mean (SD) | 13.40 (2.67) | 12.67 (2.80) | 13.26 (2.59) | 13.74 (2.61) |  < 0.001 |
Mental intactness score, mean (SD) | 9.29 (1.80) | 8.90 (1.97) | 9.22 (1.77) | 9.47 (1.74) |  < 0.001 |
Episodic memory score, mean (SD) | 4.11 (1.55) | 3.76 (1.54) | 4.03 (1.55) | 4.27 (1.54) |  < 0.001 |