Table 1.
Distribution of time-varying covariates and memory scores
| Covariate | Wave 1 (0 years) N = 1629 | Wave 2 (2 years) N = 1505 | Wave 3 (4 years) N = 1411 | Wave 4 (6 years) N = 1365 | Wave 5 (8 years) N = 1370 |
|---|---|---|---|---|---|
| Mean age (SD) | 58.6 (5.3) | 60.9 (5.3) | 62.7 (5.3) | 64.7 (5.3) | 66.6 (5.1) |
| Sex | |||||
| Female | 847 (52.0%) | 788 (52.4%) | 746 (52.9%) | 715 (52.4%) | 719 (52.5%) |
| Male | 782 (48.9%) | 717 (47.6%) | 665 (47.1%) | 649 (47.6%) | 651 (47.5%) |
| Total | 1629 (100%) | 1505 (100%) | 1411 (100%) | 1364 (100%) | 1370 (100%) |
| Retired | |||||
| Yes | 0 (0%) | 533 (35.4%) | 729 (51.7%) | 994 (72.8%) | 1370 (100%) |
| No | 1629 (100%) | 972 (64.6%) | 682 (48.3%) | 371 (27.2%) | 0 (0%) |
| Total | 1629 (100%) | 1505 (100%) | 1411 (100%) | 1365 (100%) | 1370 (100%) |
| Diabetes | |||||
| Yes | 67 (4.1%) | 83 (5.5%) | 102 (7.2%) | 110 (8.1%) | 131 (9.6%) |
| No | 1562 (95.9%) | 1422 (94.5%) | 1309 (92.8%) | 1253 (91.9%) | 1239 (9.6%) |
| Total | 1629 (100%) | 1505 (100%) | 1411 (100%) | 1363 (100%) | 1370 (100%) |
| Hypertension | |||||
| Yes | 509 (31.3%) | 555 (36.9%) | 571 (40.5%) | 589 (43.2%) | 619 (45.2%) |
| No | 1120 (68.8%) | 950 (36.9%) | 840 (59.5%) | 775 (56.8%) | 751 (54.8%) |
| Total | 1629 (100%) | 1505 (100%) | 1411 (100%) | 1364 (100%) | 1370 (100%) |
| Stroke | |||||
| Yes | 15 (0.9%) | 24 (1.6%) | 28 (2.0%) | 33 (2.4%) | 40 (2.9%) |
| No | 1614 (99.1%) | 1481 (98.4%) | 1383 (98.0%) | 1330 (97.6%) | 1330 (97.1%) |
| Total | 1629 (100%) | 1505 (100%) | 1411 (100%) | 1363 (100%) | 1370 (100%) |
| Myocardial infarction | |||||
| Yes | 44 (2.7%) | 55 (3.7%) | 68 (4.8%) | 68 (5.0%) | 67 (4.9%) |
| No | 1585 (97.3%) | 1450 (96.4%) | 1343 (95.2%) | 1295 (95.0%) | 1303 (95.1%) |
| Total | 1629 (100%) | 1505 (100%) | 1411 (100%) | 1363 (100%) | 1370 (100%) |
| Depression score | 1.16 (1.67) | 1.28 (1.76) | 1.15 (1.69) | 1.12 (1.73) | 1.23 (1.81) |
| Total | 1592 | 1484 | 1395 | 1327 | 1330 |
| Self-reported health score | 1.64 (0.73) | 1.72 (0.77) | 1.96 (0.73) | 1.76 (0.77) | 1.77 (0.76) |
| Total | 1621 | 1499 | 1404 | 1340 | 1337 |
| Alcohol | |||||
| Abstainer | 538 (33.2%) | 466 (33.6%) | 436 (34.9%) | 410 (33.9%) | 503 (39.3%) |
| Light | 586 (36.1%) | 372 (26.8%) | 342 (27.4%) | 330 (27.3%) | 305 (23.8%) |
| Moderate | 498 (30.7%) | 549 (39.6%) | 472 (37.8%) | 470 (38.8%) | 471 (36.8%) |
| Total | 1622 (100%) | 1387 (100%) | 1250 (100%) | 1210 (100%) | 1279 (100%) |
| Education | |||||
| Low | 671 (41.2%) | 603 (40.1%) | 478 (33.9%) | 502 (36.9%) | 532 (39.0%) |
| Medium | 438 (26.9%) | 415 (27.6%) | 399 (28.3%) | 368 (27.0%) | 351 (25.8%) |
| High | 518 (31.8%) | 486 (32.3%) | 534 (37.9%) | 492 (36.1%) | 480 (35.2%) |
| Total | 1627 (100%) | 1504 (100%) | 1411 (100%) | 1362 (100%) | 1363 (100%) |
| Occupational class | |||||
| Professional/Managerial | 608 (38.6%) | 522 (34.7%) | 479 (34.0%) | 453 (33.2%) | 464 (33.9%) |
| Intermediate | 372 (23.6%) | 396 (26.4%) | 386 (27.4%) | 376 (27.6%) | 369 (27.0%) |
| Lower | 595 (37.8%) | 585 (38.9%) | 544 (38.6%) | 534 (39.1%) | 535 (39.1%) |
| Total | 1575 (100%) | 1503 (100%) | 1409 (100%) | 1363 (100%) | 1368 (100%) |
| Memory tests | |||||
| Immediate recall | 6.01 (1.61) | 6.15 (1.59) | 6.15 (1.65) | 6.13 (1.60) | 6.11 (1.67) |
| Delayed recall | 4.64 (1.92) | 4.86 (1.90) | 4.96 (1.91) | 4.87 (1.90) | 4.85 (2.00) |
| Episodic memory | 10.66 (3.20) | 11.02 (3.18) | 11.10 (3.25) | 11.00 (3.25) | 10.96 (3.41) |
| Total | 1602 | 1498 | 1401 | 1339 | 1333 |