Table 1.
Characteristics of Study Participants
| Variable | Total (N = 5,490) | By social isolation | By loneliness | ||||
|---|---|---|---|---|---|---|---|
| Not socially isolated (n = 3,682) | Socially isolated (n = 1,248) | Missing (n = 560) | Not lonely (n = 4,563) | Lonely (n = 595) | Missing (n = 332) | ||
| UCLA Loneliness Scale | |||||||
| Not lonely | 4,563 (88.5%) | 3,350 (93.2%) | 895 (74.6%) | 318 | |||
| Lonely | 595 (11.5%) | 245 (6.8%) | 305 (25.4%) | 45 | |||
| Luben Social Network Scale | |||||||
| Not socially isolated | 3,682 (74.7%) | 3,350 (78.9%) | 245 (44.5%) | 87 | |||
| Socially isolated | 1,248 (25.3%) | 895 (21.1%) | 305 (55.5%) | 48 | |||
| Age, mean (SD) | 80.9 (4.9) | 80.5 (4.7) | 81.5 (5.4) | 82.1 (5.0) | 80.7 (4.8) | 81.4 (5.1) | 82.4 (5.1) |
| Gender | |||||||
| Male | 2,310 (42.1%) | 1,506 (40.9%) | 632 (50.6%) | 172 | 1,937 (42.5%) | 279 (46.9%) | 94 |
| Female | 3,180 (57.9%) | 2,176 (59.1%) | 616 (49.4%) | 388 | 2,626 (57.5%) | 316 (53.1%) | 238 |
| Education period | |||||||
| Junior high school graduate and below | 2,782 (54.4%) | 1,883 (53.4%) | 639 (53.4%) | 260 | 2,300 (52.7%) | 346 (60.9%) | 136 |
| Income | |||||||
| Less than 3,000,000 Yen/year | 3,405 (72.8%) | 2,293 (71.1%) | 849 (76.4%) | 263 | 2,871 (71.5%) | 410 (79.6%) | 124 |
| History of diabetes mellitus | 761 (13.9%) | 466 (12.7%) | 216 (17.3%) | 79 | 596 (13.1%) | 121 (20.3%) | 44 |
| History of stroke | 166 (3.0%) | 92 (2.5%) | 57 (4.6%) | 17 | 113 (2.5%) | 33 (5.5%) | 20 |
| History of depression | 109 (2.0%) | 54 (1.5%) | 45 (3.6%) | 10 | 79 (1.7%) | 24 (4.0%) | 6 |
| Mini-Cog test | |||||||
| 2 points or less | 46 (6.2%) | 29 (5.7%) | 9 (5.1%) | 8 | 36 (5.6%) | 7 (8.5%) | 3 |
| Smoking status | |||||||
| Current smoker | 344 (6.6%) | 229 (6.5%) | 93 (7.7%) | 22 | 286 (6.6%) | 44 (7.7%) | 14 |
| High alcohol consumption | |||||||
| 3 days or more/week | 1,117 (21.4%) | 759 (21.6%) | 266 (22.1%) | 92 | 953 (21.8%) | 117 (20.6%) | 47 |
| The number of teeth | |||||||
| 20 or more | 1,477 (28.1%) | 1,016 (28.6%) | 338 (28.1%) | 123 | 1,290 (29.2%) | 127 (22.2%) | 60 |
| Less than 20 | 3,785 (71.9%) | 2,540 (71.4%) | 866 (71.9%) | 379 | 3,125 (70.8%) | 444 (77.8%) | 216 |
| Frequency of brushing teeth | |||||||
| Not everyday | 638 (12.0%) | 387 (10.8%) | 188 (15.5%) | 63 | 478 (10.8%) | 116 (20.2%) | 44 |
| Ability to chew foods | |||||||
| Can’t chew | 148 (2.7%) | 75 (2.1%) | 58 (4.7%) | 15 | 86 (1.9%) | 44 (7.5%) | 18 |
Notes: SD = standard deviation; UCLA = University of California, Los Angeles. All percentages exclude missing responses. Among the 5,490 participants in this study, the age range was from 75 to 102 years old.