Table 1. Baseline Characteristics of the Study Population by Dementia Status.
| Characteristic | No. (%) | P Value | |
|---|---|---|---|
| Dementia-Free (n = 1216) | Incident Dementia (n = 386) | ||
| Age, mean (SD), y | 78.5 (7.6) | 83.0 (6.0) | <.001 |
| Female | 924 (76.0) | 292 (75.7) | .89 |
| Life course cognitive reserve factors | |||
| Education, mean (SD), y | 14.8 (3.3) | 14.5 (3.1) | .08 |
| Early-life cognitive activity, mean (SD) | 3.1 (0.6) | 3.0 (0.6) | .11 |
| Midlife cognitive activity, mean (SD) | 3.3 (0.6) | 3.2 (0.7) | .04 |
| Late-life cognitive activity, mean (SD) | 3.2 (0.7) | 3.1 (0.8) | .003 |
| Social activity in late life, mean (SD) | 2.7 (0.6) | 2.5 (0.6) | <.001 |
| Social network, median (IQR) | 6.0 (3.0-10.0) | 5.0 (3.0-9.0) | .03 |
| Smoking status | |||
| Never | 696 (57.2) | 245 (63.5) | .08 |
| Ever | 483 (39.7) | 133 (34.5) | |
| Current | 37 (3.1) | 8 (2.0) | |
| Alcohol consumptiona | |||
| Never/occasional | 731 (60.8) | 261 (67.6) | .03 |
| Light/moderate | 340 (27.6) | 89 (23.1) | |
| Heavy | 144 (11.7) | 36 (9.3) | |
| Physical activity, median (IQR) | 2.4 (0.8-4.5) | 2.5 (1.0-4.7) | .98 |
| BMI, mean (SD)b | 27.7 (5.6) | 26.5 (4.5) | <.001 |
| MMSE score, median (IQR)a | 29.0 (28.0-30.0) | 28.0 (26.0-29.0) | <.001 |
| Heart diseasea | 109 (9.0) | 36 (9.3) | .83 |
| Hypertension | 826 (67.9) | 242 (62.7) | .06 |
| Cerebrovascular diseasec | 96 (8.7) | 41 (11.3) | .14 |
| Type 2 diabetes | 187 (15.4) | 39 (10.1) | .01 |
| Any APOE ɛ4d | 224 (19.5) | 121 (32.0) | <.001 |
| Death during follow-up | 458 (37.7) | 289 (74.9) | <.001 |
Abbreviations: APOE ɛ4, apolipoprotein ɛ4 allele; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); IQR, interquartile range; MMSE, Mini-Mental State Examination.
a
Data missing for 1 participant.
b
Data missing for 30 participants.
c
Data missing for 139 participants.
d
Data missing for 72 participants.