Table 1 Baseline characteristics of participants according to facial age status
|  | Younger than your age (N = 147,835) | About your age (N = 45,242) | Older than your age (N = 2252) | Overall (N = 195,329) | P value |
|---|---|---|---|---|---|
Age | |||||
 Mean (SD) | 64.1 (2.89) | 64.1 (2.76) | 63.7 (2.70) | 64.1 (2.86) | < 0.001 |
White British, n (%) | 134,979 (91.3) | 42,065 (93.0) | 1970 (87.5) | 179,014 (91.6) | < 0.001 |
Women, n (%) | 80,288 (54.3) | 21,621 (47.8) | 661 (29.4) | 102,570 (52.5) | < 0.001 |
Smoking |  |  |  |  | < 0.001 |
 Current | 11,255 (7.6) | 4148 (9.2) | 349 (15.5) | 15,752 (8.1) |  |
 Past | 61,164 (41.4) | 19,107 (42.2) | 1013 (45.0) | 81,284 (41.6) |  |
 Never | 75,416 (51.0) | 21,987 (48.6) | 890(39.5) | 98,293 (50.4) |  |
Education level |  |  |  |  | < 0.001 |
 College or University degree | 38,696 (26.2) | 11,283 (24.9) | 576 (25.6) | 50,555 (25.9) |  |
 A levels or equivalent | 34,496 (23.3) | 10,266 (22.7) | 485 (21.5) | 45,247 (23.2) |  |
 O levels or equivalent | 34,603 (23.4) | 9931 (22.0) | 427 (19.0) | 44,961 (23.0) |  |
 None of the above; NA | 40,040 (27.1) | 13,762 (30.4) | 764 (33.9) | 54,566 (27.9) |  |
Alcohol intake |  |  |  |  | < 0.001 |
 Current | 135,927 (91.9) | 40,986 (90.6) | 1910 (84.8) | 178,823 (91.5) |  |
 Previous | 5271 (3.6) | 1887 (4.2) | 161 (7.1) | 7319 (3.7) |  |
 Never | 6637 (4.5) | 2369 (5.2) | 181 (8.0) | 9187 (4.7%) |  |
Regular physical activitya |  |  |  |  | < 0.001 |
 No | 40,723 (27.5) | 14,102 (31.2) | 836 (37.1) | 55,661 (28.5) |  |
 Yes | 83,702 (56.6) | 23,951 (52.9) | 1009 (44.8) | 108,662 (55.6) |  |
 Missing | 23,410 (15.8) | 7189 (15.9) | 407 (18.1) | 31,006 (15.9) |  |
Positive family history of AD, n (%) | 22,271 (15.1) | 6849 (15.1) | 314 (13.9) | 29,434 (15.1) | 0.301 |
Time spent outdoors summer, hour | 4.23 (2.30) | 4.18 (2.29) | 4.07 (2.52) | 4.21 (2.30) | < 0.001 |
Depressive symptomsb |  |  |  |  | < 0.001 |
 No | 133,690 (90.4) | 40,712 (90.0) | 1862 (82.7) | 176,264 (90.2) |  |
 Yes | 5613 (3.8) | 1722 (3.8) | 191 (8.5) | 7526 (3.9) |  |
 Missing | 8532 (5.8) | 2808 (6.2) | 199 (8.8) | 11,539 (5.9) |  |
At least one APOE ε4 allele |  |  |  |  | < 0.001 |
 No | 87,887 (59.4) | 26,465 (58.5) | 1258 (55.9) | 115,610 (59.2) |  |
 Yes | 34,532 (23.4) | 10,478 (23.2) | 531 (23.6) | 45,541 (23.3) |  |
 Missing | 25,416 (17.2) | 8299 (18.3) | 463 (20.6) | 34,178 (17.5) |  |
BMI, kg/m2 | 27.5 (4.45) | 27.8 (4.65) | 28.3 (5.20) | 27.6 (4.51) | < 0.001 |
Cancer at baseline, n (%) | 15,179 (10.3) | 5991 (13.2) | 493 (21.9) | 21,663 (11.1) | 0.016 |
CVD at baseline, n (%) | 20,408 (13.8) | 6467 (14.3) | 333 (14.8) | 27,208 (13.9) | < 0.001 |
T2DM at baseline, n (%) | 9340 (6.3) | 3191 (7.1) | 252 (11.2) | 12,783 (6.5) | < 0.001 |
Hypertension at baseline, n (%) | 58,362 (39.5) | 19,155 (42.3) | 1133 (50.3) | 78,650 (40.3) | < 0.001 |
CRP, mg/L | 2.69 (4.38) | 2.91 (4.92) | 3.18 (5.03) | 2.75 (4.52) | < 0.001 |
Use of sun/UV protection |  |  |  |  | < 0.001 |
 never/rarely | 15,005 (10.1) | 4981 (11.0) | 432 (19.2) | 20,418 (10.5) |  |
 sometimes | 49,651 (33.6) | 16,275 (36.0) | 792 (35.1) | 66,718 (34.2) |  |
 most of the time | 49,975 (33.8) | 15,225 (33.7) | 615 (27.3) | 65,815 (33.7) |  |
 always | 32,354 (21.9) | 8445 (18.7) | 378 (16.8) | 41,177 (21.1) |  |
 do not go out in sunshine | 850 (0.6) | 316 (0.7) | 35 (1.6) | 1201 (0.6) |  |