Table 1. Characteristics of study participants by trajectory patterns and sex at baseline.
| Characteristics of study participants | ||||||||||||
| Men (n = 1,049) | Women (n = 1,633) | |||||||||||
| Slowly declining (n = 674) | Persistently disabled (n = 47) | Rapidly declining (n = 328) | Slowly declining (n = 1,301) | Persistently disabled (n = 61) | Rapidly declining (n = 271) | |||||||
| n | % | n | % | n | % | n | % | n | % | n | % | |
| Age | ||||||||||||
| 65–74 | 154 | 22.8 | 8 | 17.0 | 92 | 28.0 | 213 | 16.4 | 11 | 18.0 | 60 | 22.1 |
| 75–84 | 389 | 57.7 | 31 | 66.0 | 156 | 47.6 | 760 | 58.4 | 34 | 55.7 | 150 | 55.4 |
| 85– | 131 | 19.4 | 8 | 17.0 | 80 | 24.4 | 328 | 25.2 | 16 | 26.2 | 61 | 22.5 |
| Marital status | ||||||||||||
| Married | 490 | 72.7 | 40 | 85.1 | 236 | 72.0 | 469 | 36.0 | 28 | 45.9 | 101 | 37.3 |
| Single | 120 | 17.8 | 5 | 10.6 | 60 | 18.3 | 693 | 53.3 | 27 | 44.3 | 145 | 53.5 |
| Missing | 64 | 9.5 | 2 | 4.3 | 32 | 9.8 | 139 | 10.7 | 6 | 9.8 | 25 | 9.2 |
| Education (years) | ||||||||||||
| ≤9 | 346 | 51.3 | 33 | 70.2 | 177 | 54.0 | 718 | 55.2 | 38 | 62.3 | 165 | 60.9 |
| ≥10 | 267 | 39.6 | 10 | 21.3 | 114 | 34.8 | 417 | 32.1 | 14 | 23.0 | 73 | 26.9 |
| Missing/others | 61 | 9.1 | 4 | 8.5 | 37 | 11.3 | 166 | 12.8 | 9 | 14.8 | 33 | 12.2 |
| Equivalized income | ||||||||||||
| 1.99 million yen or less | 292 | 43.3 | 26 | 55.3 | 145 | 44.2 | 480 | 36.9 | 24 | 39.3 | 103 | 38.0 |
| 2 million yen or more | 213 | 31.6 | 16 | 34.0 | 98 | 29.9 | 315 | 24.2 | 14 | 23.0 | 70 | 25.8 |
| Missing | 169 | 25.1 | 5 | 10.6 | 85 | 25.9 | 506 | 38.9 | 23 | 37.7 | 98 | 36.2 |
| Household composition | ||||||||||||
| With spouse/children/others | 560 | 83.1 | 44 | 93.6 | 276 | 84.1 | 946 | 72.7 | 44 | 72.1 | 211 | 77.9 |
| Live alone | 64 | 9.5 | 2 | 4.3 | 22 | 6.7 | 254 | 19.5 | 10 | 16.4 | 42 | 15.5 |
| Missing | 50 | 7.4 | 1 | 2.1 | 30 | 9.1 | 101 | 7.8 | 7 | 11.5 | 18 | 6.6 |
| Urbanization | ||||||||||||
| Urban (>1,500 population/km2) | 88 | 13.1 | 7 | 14.9 | 42 | 12.8 | 156 | 12.0 | 4 | 6.6 | 33 | 12.2 |
| Semi-urban (1,000–1,500 population/km2) | 258 | 38.3 | 12 | 25.5 | 113 | 34.5 | 448 | 34.4 | 20 | 32.8 | 78 | 28.8 |
| Rural (<1,000 population/km2) | 328 | 48.7 | 28 | 59.6 | 173 | 52.7 | 697 | 53.6 | 37 | 60.7 | 160 | 59.0 |
| Body mass index | ||||||||||||
| <18.5 | 75 | 11.1 | 11 | 23.4 | 46 | 14.0 | 129 | 9.9 | 6 | 9.8 | 35 | 12.9 |
| 18.5–24.9 | 402 | 59.6 | 24 | 51.1 | 182 | 55.5 | 672 | 51.7 | 28 | 45.9 | 144 | 53.1 |
| ≥25 | 115 | 17.1 | 8 | 17.0 | 51 | 15.5 | 279 | 21.4 | 12 | 19.7 | 47 | 17.3 |
| Missing | 82 | 12.2 | 4 | 8.5 | 49 | 14.9 | 221 | 17.0 | 15 | 24.6 | 45 | 16.6 |
| Current medical history | ||||||||||||
| No | 409 | 60.7 | 19 | 40.4 | 170 | 51.8 | 644 | 49.5 | 31 | 50.8 | 138 | 50.9 |
| Yes | 265 | 39.3 | 28 | 59.6 | 158 | 48.2 | 657 | 50.5 | 30 | 49.2 | 133 | 49.1 |
| Self-rated health | ||||||||||||
| Very good/Good | 364 | 54.0 | 15 | 31.9 | 176 | 53.7 | 736 | 56.6 | 28 | 45.9 | 137 | 50.6 |
| Poor/very poor | 283 | 42.0 | 31 | 66.0 | 144 | 43.9 | 511 | 39.3 | 32 | 52.5 | 122 | 45.0 |
| Missing | 27 | 4.0 | 1 | 2.1 | 8 | 2.4 | 54 | 4.2 | 1 | 1.6 | 12 | 4.4 |
| Depressive symptoms (GDS-15) | ||||||||||||
| No depressive symptoms (GDS-15 <6) | 315 | 46.7 | 14 | 29.8 | 152 | 46.3 | 580 | 44.6 | 25 | 41.0 | 116 | 42.8 |
| Depressive symptoms (GDS-15 ≥6) | 212 | 31.5 | 25 | 53.2 | 101 | 30.8 | 339 | 26.1 | 16 | 26.2 | 71 | 26.2 |
| Missing | 147 | 21.8 | 8 | 17.0 | 75 | 22.9 | 382 | 29.4 | 20 | 32.8 | 84 | 31.0 |
| Intellectual activity | ||||||||||||
| 4 points (full marks) | 339 | 50.3 | 19 | 40.4 | 146 | 44.5 | 564 | 43.4 | 20 | 32.8 | 105 | 38.7 |
| 3 points and under | 258 | 38.3 | 24 | 51.1 | 147 | 44.8 | 570 | 43.8 | 30 | 49.2 | 129 | 47.6 |
| Missing | 77 | 11.4 | 4 | 8.5 | 35 | 10.7 | 167 | 12.8 | 11 | 18.0 | 37 | 13.7 |
| Instrumental activities of daily living | ||||||||||||
| 5 points (full marks) | 321 | 47.6 | 16 | 34.0 | 140 | 42.7 | 652 | 50.1 | 19 | 31.1 | 114 | 42.1 |
| 4 points and under | 286 | 42.4 | 28 | 59.6 | 155 | 47.3 | 479 | 36.8 | 33 | 54.1 | 122 | 45.0 |
| Missing | 67 | 9.9 | 3 | 6.4 | 33 | 10.1 | 170 | 13.1 | 9 | 14.8 | 35 | 12.9 |
| Frequency of outings | ||||||||||||
| Higher | 518 | 76.9 | 30 | 63.8 | 243 | 74.1 | 949 | 72.9 | 37 | 60.7 | 185 | 68.3 |
| Low | 99 | 14.7 | 15 | 31.9 | 60 | 18.3 | 240 | 18.4 | 16 | 26.2 | 61 | 22.5 |
| Missing | 57 | 8.5 | 2 | 4.3 | 25 | 7.6 | 112 | 8.6 | 8 | 13.1 | 25 | 9.2 |
GDS-15, short version of the Geriatric Depression Scale.