Table 1.
Descriptive statistics of baseline characteristics for UK Biobank participants included in the study
| Characteristic | All (n = 41,484) | Follow-up | ||
|---|---|---|---|---|
| No diagnosis of dementia (n = 34,570) | Diagnosed with dementia (n = 6914) | P | ||
| APOE(ε4) carrier (n,%) | < 0.001 | |||
| no | 30,028 (72.4) | 26,533 (76.8) | 3495 (50.5) | |
| yes | 11,456 (27.6) | 8037 (23.2) | 3419 (49.5) | |
| Age (years old) | 64.4 (2.9) | 64 (62,66) | 66 (64,68) | < 0.001 |
| Attendance/disability/mobility allowance (n,%) | < 0.001 | |||
| attendance allowance | 494 (1.2) | 312 (0.9) | 182 (2.6) | |
| disability living allowance | 2188 (5.3) | 1528 (4.4) | 660 (9.5) | |
| blue badge | 881 (2.1) | 656 (1.9) | 225 (3.3) | |
| none of the above | 37,921 (91.4) | 32,074 (92.8) | 5847 (84.6) | |
| Long-standing illness, disability or infirmity (n,%) | < 0.001 | |||
| no | 24,983 (60.2) | 21,702 (62.8) | 3281 (47.5) | |
| yes | 16,501 (39.8) | 12,868 (37.2) | 3633 (52.5) | |
| Diabetes diagnosed (n,%) | < 0.001 | |||
| no | 38,230 (92.2) | 32,242 (93.3) | 5988 (86.6) | |
| yes | 3254 (7.8) | 2328 (6.7) | 926 (13.4) | |
| Cognitive function-Reaction time (milliseconds) | 594.4 (126.3) | 567 (508,645) | 594 (527,680) | < 0.001 |
| illnesses of mother (n,%) | < 0.001 | |||
| heart disease | 3718 (9) | 3098 (9) | 620 (9) | |
| stroke | 3178 (7.7) | 2659 (7.7) | 519 (7.5) | |
| lung cancer | 1021 (2.5) | 859 (2.5) | 162 (2.3) | |
| bowel cance | 1564 (3.8) | 1309 (3.8) | 255 (3.7) | |
| breast cancer | 2060 (5) | 1718 (5) | 342 (4.9) | |
| chronic bronchitis/emphysema | 1598 (3.9) | 1312 (3.8) | 286 (4.1) | |
| high blood pressure | 7352 (17.7) | 6359 (18.4) | 993 (14.4) | |
| diabetes | 2919 (7) | 2465 (7.1) | 454 (6.6) | |
| alzheimer's disease/dementia | 4347 (10.5) | 3323 (9.6) | 1024 (14.8) | |
| parkinson's disease | 745 (1.8) | 606 (1.8) | 139 (2) | |
| severe depression | 2336 (5.6) | 1916 (5.5) | 420 (6.1) | |
| none of the above | 10,646 (25.7) | 8946 (25.9) | 1700 (24.6) | |
| Alcohol versus 10 years previously (n,%) | < 0.001 | |||
| more nowadays | 5908 (14.2) | 5119 (14.8) | 789 (11.4) | |
| about the same | 16,715 (40.3) | 14,194 (41.1) | 2521 (36.5) | |
| less nowadays | 18,861 (45.5) | 15,257 (44.1) | 3604 (52.1) | |
| Dementia PRS | -0.00222(-0.00303, -0.00129) | -0.002256(-0.00307, -0.00136) | -0.00205(-0.00292, -0.00096) | < 0.001 |
| Average total household income before tax (￡) | < 0.001 | |||
| less than 18,000 | 15,579 (37.6) | 12,208 (35.3) | 3371 (48.8) | |
| 18,000 to 30,999 | 13,413 (32.3) | 11,292 (32.7) | 2121 (30.7) | |
| 31,000 to 51,999 | 7984 (19.2) | 6996 (20.2) | 988 (14.3) | |
| 52,000 to 100,000 | 3640 (8.8) | 3288 (9.5) | 352 (5.1) | |
| greater than 100,000 | 868 (2.1) | 786 (2.3) | 82 (1.2) | |
| Own or rent accommodation lived in (n,%) | < 0.001 | |||
| own outright | 32,013 (77.2) | 26,846 (77.7) | 5167 (74.7) | |
| own with a mortgage | 5846 (14.1) | 5022 (14.5) | 824 (11.9) | |
| rent from local authority, local council, housing association | 2348 (5.7) | 1687 (4.9) | 661 (9.6) | |
| rent from private landlord or letting agency | 784 (1.9) | 631 (1.8) | 153 (2.2) | |
| pay part rent and part mortgage | 78 (0.2) | 62 (0.2) | 16 (0.2) | |
| live in accommodation rent free | 238 (0.6) | 190 (0.5) | 48 (0.7) | |
| none of the above | 177 (0.4) | 132 (0.4) | 45 (0.7) | |
| Non-cancer illnesses | 2.4 (2) | 2 (1,3) | 3 (1,4) | < 0.001 |
| Never eat eggs, dairy, wheat, sugar (n,%) | < 0.001 | |||
| eggs or foods containing eggs | 1511 (3.6) | 1108 (3.2) | 403 (5.8) | |
| dairy products | 719 (1.7) | 558 (1.6) | 161 (2.3) | |
| wheat products | 891 (2.1) | 680 (2) | 211 (3.1) | |
| sugar or foods/drinks containing sugar | 8900 (21.5) | 7224 (20.9) | 1676 (24.2) | |
| eat all of the above | 29,463 (71) | 25,000 (72.3) | 4463 (64.6) | |
| Leg fat percentage (right) | 32.7 (10.7) | 34.3 (23.1,42) | 31.4 (22.4,41.4) | < 0.001 |
| Time spent watching television(hours/day) | 2.8 (2.9) | 3 (2,4) | 3 (2,4) | < 0.001 |
| Stroke | ||||
| no | 40,423 (97.4) | 33,851 (97.9) | 6572 (95.1) | |
| yes | 1061 (2.6) | 719 (2.1) | 342 (4.9) | |
| Falls in the last year (n,%) | < 0.001 | |||
| no falls | 31,923 (77) | 27,068 (78.3) | 4855 (70.2) | |
| only one fall | 6340 (15.3) | 5112 (14.8) | 1228 (17.8) | |
| more than one fall | 3221 (7.8) | 2390 (6.9) | 831 (12) | |
| Types of physical activity in last 4 weeks (n,%) | < 0.001 | |||
| walking for pleasure | 29,794 (71.8) | 25,216 (72.9) | 4578 (66.2) | |
| Other exercises (eg: swimming, cycling) | 4343 (10.5) | 3644 (10.5) | 699 (10.1) | |
| strenuous sports | 193 (0.5) | 166 (0.5) | 27 (0.4) | |
| light DIY (eg: pruning) | 3260 (7.9) | 2589 (7.5) | 671 (9.7) | |
| heavy DIY (eg: weeding) | 1298 (3.1) | 1022 (3) | 276 (4) | |
| none of the above | 2596 (6.3) | 1933 (5.6) | 663 (9.6) | |
| Frequency of depressed mood in last 2 weeks (n,%) | < 0.001 | |||
| not at all | 33,661 (81.1) | 28,334 (82) | 5327 (77) | |
| several days | 6199 (14.9) | 4987 (14.4) | 1212 (17.5) | |
| more than half the days | 1029 (2.5) | 810 (2.3) | 219 (3.2) | |
| nearly every day | 595 (1.4) | 439 (1.3) | 156 (2.3) | |
| Taking other prescription medications | < 0.001 | |||
| no | 17,197 (41.5) | 15,089 (43.6) | 2108 (30.5) | |
| yes | 24,287 (58.5) | 19,481 (56.4) | 4806 (69.5) | |
| Serious medical condition/disability (n,%) | < 0.001 | |||
| no | 31,109 (75) | 26,473 (76.6) | 4636 (67.1) | |
| yes | 10,375 (25) | 8097 (23.4) | 2278 (32.9) | |
| Type of accommodation lived in (n,%) | < 0.001 | |||
| a house or bungalow | 37,406 (90.2) | 31,348 (90.7) | 6058 (87.6) | |
| a flat, maisonette or apartment | 3651 (8.8) | 2914 (8.4) | 737 (10.7) | |
| mobile or temporary structure | 71 (0.2) | 54 (0.2) | 17 (0.2) | |
| sheltered accommodation | 210 (0.5) | 141 (0.4) | 69 (1) | |
| care home | 9 (0) | 1 (0) | 8 (0.1) | |
| none of the above | 137 (0.3) | 112 (0.3) | 25 (0.4) | |
| Frequency of unenthusiasm/disinterest in last 2 weeks (n,%) | < 0.001 | |||
| not at all | 34,463 (83.1) | 29,050 (84) | 5413 (78.3) | |
| several days | 5404 (13) | 4288 (12.4) | 1116 (16.1) | |
| more than half the days | 939 (2.3) | 721 (2.1) | 218 (3.2) | |
| nearly every day | 678 (1.6) | 511 (1.5) | 167 (2.4) | |
| Spirometry (Peak expiratory flow) (litres/min) | 355.6 (131.7) | 359.1 (131) | 337.9 (133.5) | < 0.001 |
| Mouth/teeth dental problems (n,%) | < 0.001 | |||
| mouth ulcers | 3963 (9.6) | 3259 (9.4) | 704 (10.2) | |
| painful gums | 821 (2) | 647 (1.9) | 174 (2.5) | |
| bleeding gums | 3023 (7.3) | 2628 (7.6) | 395 (5.7) | |
| loose teeth | 1154 (2.8) | 939 (2.7) | 215 (3.1) | |
| toothache | 720 (1.7) | 575 (1.7) | 145 (2.1) | |
| dentures | 9050 (21.8) | 7067 (20.4) | 1983 (28.7) | |
| none of the above | 22,753 (54.8) | 19,455 (56.3) | 3298 (47.7) | |
| Leg fat mass (left)(Kg) | 4.3 (1.8) | 4 (2.9,5.3) | 3.9 (2.8,5.2) | < 0.001 |
| Drive faster than motorway speed limit (n,%) | < 0.001 | |||
| never/rarely | 20,914 (50.4) | 17,024 (49.2) | 3890 (56.3) | |
| sometimes | 13,628 (32.9) | 11,708 (33.9) | 1920 (27.8) | |
| often | 2505 (6) | 2238 (6.5) | 267 (3.9) | |
| most of the time | 795 (1.9) | 718 (2.1) | 77 (1.1) | |
| do not drive on the motorway | 3642 (8.8) | 2882 (8.3) | 760 (11) | |
| Current employment status (n,%) | < 0.001 | |||
| in paid employment or self-employed | 10,278 (24.8) | 9253 (26.8) | 1025 (14.8) | |
| retired | 29,532 (71.2) | 23,955 (69.3) | 5577 (80.7) | |
| looking after home and/or family | 341 (0.8) | 292 (0.8) | 49 (0.7) | |
| unable to work because of sickness or disability | 696 (1.7) | 523 (1.5) | 173 (2.5) | |
| unemployed | 233 (0.6) | 201 (0.6) | 32 (0.5) | |
| doing unpaid or voluntary work | 181 (0.4) | 151 (0.4) | 30 (0.4) | |
| full or part-time student | 19 (0) | 18 (0.1) | 1 (0) | |
| none of the above | 204 (0.5) | 177 (0.5) | 27 (0.4) | |
| Frequency of tenseness/restlessness in last 2 weeks (n,%) | < 0.001 | |||
| not at all | 32,294 (77.8) | 27,179 (78.6) | 5115 (74) | |
| several days | 7721 (18.6) | 6298 (18.2) | 1423 (20.6) | |
| more than half the days | 911 (2.2) | 683 (2) | 228 (3.3) | |
| nearly every day | 558 (1.3) | 410 (1.2) | 148 (2.1) | |
| Country of birth (UK/elsewhere) (n,%) | < 0.001 | |||
| england | 33,201 (80) | 27,694 (80.1) | 5507 (79.6) | |
| wales | 1801 (4.3) | 1594 (4.6) | 207 (3) | |
| scotland | 3152 (7.6) | 2579 (7.5) | 573 (8.3) | |
| Northern Ireland | 270 (0.7) | 215 (0.6) | 55 (0.8) | |
| republic of Ireland | 521 (1.3) | 401 (1.2) | 120 (1.7) | |
| elsewhere | 2539 (6.1) | 2087 (6) | 452 (6.5) | |
| Follow-up time (years) | 12.6 (2.8) | 13.7 (12.9,14.4) | 10.4 (8,12.3) | |