Table 1.
Demographic information of the study participants at baseline (n = 13,462) and comparison between those with and without longitudinal follow-up data
| Variable | Overall sample (n = 13,462) | Participants with follow-up data (n = 10,219) | Participants without follow-up data (n = 3243) | P valuea |
|---|---|---|---|---|
| Age, median (IQR) | 71 (65–78) | 72 (66–78) | 70 (64–76) | < 0.001 |
| Years of education, median (IQR) | 16 (14–18) | 16 (14–18) | 16 (14–18) | 0.353 |
| Male sex, n (%) | 4629 (34.4) | 3541 (34.7) | 1088 (33.6) | 0.250 |
| Ethnicity, n (%) | < 0.001 | |||
| White | 10,633 (79.0) | 8209 (80.3) | 2424 (74.8) | |
| African American | 1924 (14.3) | 1397 (13.7) | 527 (16.3) | |
| Others/unknown | 905 (6.7) | 613 (6.0) | 292 (9.0) | |
| Marital status, n (%) | < 0.001 | |||
| Married | 7988 (59.3) | 6095 (59.6) | 1893 (58.4) | |
| Widowed | 2566 (19.1) | 2047 (20.0) | 519 (16.0) | |
| Divorced/separated | 1964 (14.6) | 1382 (13.5) | 582 (18.0) | |
| Single | 829 (6.2) | 611 (6.0) | 218 (6.7) | |
| Other/unknown | 115 (0.9) | 84 (0.8) | 31 (1.0) | |
| Living arrangement, n (%) | < 0.001 | |||
| Lives alone | 4445 (33.0) | 3409 (33.4) | 1036 (32.0) | |
| Lives with spouse | 7817 (58.1) | 5970 (58.4) | 1847 (57.0) | |
| Lives with relative or friend | 933 (6.9) | 675 (6.6) | 258 (8.0) | |
| Lives with group/other | 267 (2.0) | 165 (1.6) | 102 (3.2) | |
| Type of residence, n (%) | < 0.001 | |||
| Private residence | 12,207 (90.7) | 9146 (89.5) | 3061 (94.4) | |
| Retirement community | 950 (7.1) | 821 (8.0) | 129 (4.0) | |
| Assisted living/nursing home/other | 305 (2.3) | 252 (2.5) | 53 (1.6) | |
| Primary reason of participation, n (%) | < 0.001 | |||
| To participate in research | 11,848 (88.0) | 9088 (88.9) | 2760 (85.1) | |
| For clinical evaluation | 1240 (9.2) | 927 (9.1) | 313 (9.7) | |
| For clinical evaluation and participate in research | 359 (2.7) | 192 (1.9) | 167 (5.2) | |
| Unknown | 15 (0.1) | 12 (0.1) | 3 (0.1) | |
| Primary source of referral, n (%) | < 0.001 | |||
| Self/relative/friend | 5685 (42.2) | 4217 (41.3) | 1468 (45.3) | |
| Healthcare providers | 2441 (18.1) | 1634 (16.0) | 807 (24.9) | |
| Other | 4924 (36.6) | 4016 (39.3) | 908 (28.0) | |
| Unknown | 412 (3.1) | 352 (3.4) | 60 (1.9) | |
| Family history of dementia, n (%) | 7274 (54.0) | 5700 (55.8) | 1574 (48.5) | < 0.001 |
| Current smoker, n (%) | < 0.001 | |||
| Yes | 664 (4.9) | 507 (5.0) | 157 (4.8) | |
| No | 12,774 (94.9) | 9703 (95.0) | 3071 (94.7) | |
| Missing data | 24 (0.2) | 9 (0.1) | 15 (0.5) | |
| Diabetes mellitus, n (%) | 0.008 | |||
| Yes | 1592 (11.8) | 1160 (11.4) | 432 (13.3) | |
| No | 11,832 (87.9) | 9028 (88.4) | 2804 (86.5) | |
| Missing data | 38 (0.3) | 31 (0.3) | 7 (0.2) | |
| Hypertension, n (%) | 0.225 | |||
| Yes | 6628 (49.2) | 5074 (49.7) | 1554 (47.9) | |
| No | 6795 (50.5) | 5116 (50.1) | 1679 (51.8) | |
| Missing data | 39 (0.3) | 29 (0.3) | 10 (0.3) | |
| Hyperlipidemia, n (%) | 0.452 | |||
| Yes | 6609 (49.1) | 5038 (49.3) | 1571 (48.4) | |
| No | 6693 (49.7) | 5065 (49.6) | 1628 (50.2) | |
| Missing data | 160 (1.2) | 116 (1.1) | 44 (1.4) | |
| MMSE score, median (IQR) | 29 (28–30) | 29 (28–30) | 29 (28–30) | 0.607 |
| GDS score, median (IQR) | 1 (0–2) | 1 (0–2) | 1 (0–2) | < 0.001 |
| Presence of depression (GDS ≥ 4), n (%) | 1471 (10.9) | 993 (9.7) | 478 (14.7) | < 0.001 |
| Presence of SCD, n (%) | 3582 (26.6) | 2605 (25.5) | 977 (30.1) | < 0.001 |
IQR interquartile range, MMSE Mini-Mental State Examination, GDS geriatric depression scale, SCD subjective cognitive decline
aTest of difference between participants with and without longitudinal follow-up data: chi-square test for categorical variables and Mann-Whitney U test for continuous variables. Italicized P values are ≤ 0.05