Table 1.
Demographic characteristics of the study participants for each dementia status1
| SCD | MCI | AD | All groups | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Non-lonely (n = 24) | Lonely (n = 15) | P | Non-lonely (n = 36) | Lonely (n = 17) | P | Non-lonely (n = 46) | Lonely (n = 38) | P | Non-lonely (n = 106) | Lonely (n = 70) | P | |
| Age (years) | 70.8 ± 12.6 | 78.6 ± 14.2 | 0.080 | 77.6 ± 6.6 | 79.5 ± 8.0 | 0.359 | 78.1 ± 7.4 | 81.0 ± 6.1 | 0.062 | 76.3 ± 9.0 | 80.1 ± 8.8 | 0.007 |
| Sex (male, %) | 14 (58%) | 7 (47%) | 0.480 | 15 (41%) | 2 (12%) | 0.029 | 15 (33%) | 13 (34%) | 0.877 | 44 (44%) | 22 (31%) | 0.192 |
| Education (years) | 13.6 ± 2.8 | 12.7 ± 2.4 | 0.341 | 13.0 ± 2.4 | 11.8 ± 2.3 | 0.090 | 13.1 ± 2.7 | 12.1 ± 2.4 | 0.085 | 13.2 ± 2.6 | 12.2 ± 2.3 | 0.010 |
| Immediate family members (n) | 3.3 ± 1.5 | 3.8 ± 1.3 | 0.328 | 3.5 ± 1.5 | 3.8 ± 1.5 | 0.479 | 4.0 ± 1.2 | 4.1 ± 1.4 | 0.540 | 3.7 ± 11.4 | 4.0 ± 11.4 | 0.135 |
| BMI | 24.2 ± 4.0 | 22.9 ± 3.9 | 0.304 | 21.7 ± 3.0 | 22.4 ± 3.2 | 0.410 | 21.7 ± 3.5 | 21.9 ± 3.0 | 0.823 | 22.3 ± 3.6 | 22.2 ± 3.3 | 0.900 |
| MMSE | 28.0 ± 2.5 | 25.9 ± 3.7 | 0.050 | 25.1 ± 2.7 | 24.2 ± 4.3 | 0.467 | 20.9 ± 5.1 | 19.4 ± 4.0 | 0.128 | 23.9 ± 4.9 | 22.0 ± 4.9 | 0.012 |
| Living alone (%) | 5 (21%) | 2 (13%) | 0.550 | 4 (11%) | 5 (30%) | 0.098 | 3 (7%) | 12 (32%) | 0.003 | 12 (11%) | 19 (27%) | 0.006 |
| Drinking habits2 | 17 (71%) | 6 (40%) | 0.057 | 11 (31%) | 4 (24%) | 0.596 | 20 (44%) | 17 (45%) | 0.908 | 48 (45%) | 27 (39%) | 0.408 |
| Smoking habits3 | 7 (29%) | 6 (40%) | 0.485 | 11 (31%) | 3 (18%) | 0.320 | 11 (24%) | 12 (32%) | 0.433 | 29 (2%) | 21 (30%) | 0.675 |
| TBV | 1000.8 ± 102.4 | 925.8 ± 138.9 | 0.060 | 915.0 ± 76.1 | 861.4 ± 94.2 | 0.031 | 861.2 ± 77.8 | 859.2 ± 72.9 | 0.904 | 911.5 ± 98.4 | 874.0 ± 97.8 | 0.140 |
| GMV | 554.2 ± 56.8 | 490.8 ± 89.3 | 0.010 | 503.3 ± 45.5 | 480.2 ± 49.4 | 0.099 | 474.3 ± 49.3 | 471.9 ± 46.2 | 0.815 | 502.4 ± 58.0 | 478.0 ± 58.2 | 0.007 |
1Values are expressed as mean ± SD. Calculated using a two tailed t-test for continuous variables and the χ2 test for categorical variables. 2Drinking habits were assessed by asking the participants whether they have a habit to drinking alcohol. 3Smoking habits were measured by asking the participants whether they have a habit of smoking cigarettes. AD, a patient group with Alzheimer’s disease; BMI, body mass index; GMV, gray matter volume; MCI, a participant group with mild cognitive impairment; MMSE, Mini-Mental State Examination; SCD, a participant group diagnosed as subjective cognitive decline; TBV, total brain volume