Table 1.
Demographic characteristics and group comparisons
| LLD patients | Healthy controls | Analysis | |||||
|---|---|---|---|---|---|---|---|
| Mean (s.d.) | n | Mean (s.d.) | n | Statistics | df | p | |
| Demographics | |||||||
| Age, years | 74.0 (6.0) | 29 | 73.9 (5.9) | 30 | t = 0.09 | 58 | 0.93 |
| Female | 21 | 22 | |||||
| Lives alone | 18 | 12 | χ2 = 2.9 | 1 | 0.09 | ||
| Education, years | 10.9 (2.2) | 29 | 13.5 (3.3) | 30 | t = −3.47 | 57 | <0.001 |
| NART IQ score | 109.0 (10.2) | 29 | 114.5 (10.2) | 30 | t = −2.1 | 57 | <0.05 |
| MMSE score | 27.7 (1.8) | 29 | 28.9 (1.1) | 30 | t = −3.08 | 57 | <0.005 |
| Number of previous episodes | 6.5 (13.0) | 26 | |||||
| BMI, kg/m2 | 30.8 (6.8) | 28 | 26.4 (3.9) | 30 | t = 3.05 | 55 | <0.005 |
| Neuropsychological Z scores | |||||||
| Executive working memory | −1.2 (1.8) | 29 | 0 (0.7) | 30 | F = 6.56 | 1,59 | 0.01 |
| Attention and psychomotor speed | −2.0 (2.8) | 28 | 0 (0.9) | 30 | F = 11.09 | 1,59 | <0.005 |
| Short-term memory | −0.5 (0.8) | 29 | 0 (0.8) | 30 | F = 2.08 | 1,59 | 0.15 |
| General memory | −1.0 (1.1) | 29 | 0 (0.8) | 30 | F = 11.1 | 1,59 | <0.005 |
| Emotional processing | −0.1 (0.8) | 28 | 0 (1.0) | 29 | F = 0.06 | 1,59 | 0.81 |
| Grand score | −0.9 (0.9) | 29 | 0 (0.5) | 30 | F = 17.47 | 1,59 | <0.001 |
| MRI volumes | |||||||
| Proportion hippocampus to ICV | 0.0036 (0.00065) | 15 | 0.0037 (0.00058) | 15 | t = 0.4 | 28 | 0.68 |
| Proportion WMH to ICV | −2.1 (0.5) | 13 | −2.7 (0.7) | 14 | t = −2.5 | 25 | 0.02 |
| Clinical scale scores | |||||||
| Baseline MADRS | 28.1 (8.5) | 29 | 1.0 (1.6) | 30 | t = −17.1 | 57 | <0.001 |
| Baseline GDS | 9.7 (3.1) | 29 | 0.8 (1.4) | 30 | t = –14.3 | 57 | <0.001 |
| DSSI instrumental support | 18.5 (3.0) | 29 | 19.9 (2.3) | 30 | t = 2.0 | 57 | 0.05 |
| DSSI social support | 41.7 (5.2) | 29 | 48.4 (6.2) | 30 | t = 4.5 | 57 | <0.001 |
| IADL total score | 6.9 (1.7) | 29 | 8.0 (0.2) | 30 | t = 3.6 | 57 | <0.001 |
| SF-36 composite | 38.3 (19.9) | 29 | 79.2 (10.7) | 30 | t = 9.9 | 57 | <0.001 |
| LSNS-R total | 25.5 (7.6) | 29 | 36.9 (7.3) | 30 | t = 5.9 | 57 | <0.001 |
| UCLA Loneliness Scale total | 18.5 (7.3) | 29 | 5.6 (4.7) | 30 | t = –8.1 | 57 | <0.001 |
| Activity measures | |||||||
| Physical activity | 0.17 (0.03) | 29 | 0.20 (0.03) | 29 | t = 3.69 | 56 | <0.001 |
| Jerk | 0.001 (0.0003) | 29 | 0.001 (0.0002) | 29 | t = 4.06 | 56 | <0.001 |
| Entropy | 2.50 (0.39) | 29 | 2.81 (0.26) | 29 | t = 3.56 | 56 | 0.003 |
LLD, Late-life depression; s.d., standard deviation; df, degrees of freedom; NART, National Adult Reading Test; IQ, intelligence quotient; MMSE, Mini Mental State Examination; BMI, body mass index; MRI, magnetic resonance imaging; ICV, intracranial volume; WMH, white matter hyperintensity; MADRS, Montgomery–Åsberg Depression Rating Scale; GDS, Geriatric Depression Scale; DSSI, Duke Social Support Index; IADL, Instrumental Activities of Daily Living Scale; SF-36, 36-item Short-Form Health Survey; LSNS-R, Lubben Social Network Scale–Revised.