Table 1 Number of participants in each survey from baseline until follow-up
| Â | Â | Â | Cognitive impairment* | |
|---|---|---|---|---|
|  | Total n | % | n†| %‡ |
Third survey (baseline) | 623 | 100 | 0 | 0 |
Fourth survey | 610 | 97.9 | 146 | 23.9 |
Fifth survey | 549 | 88.1 | 149 | 27.1 |
Sixth survey | 480 | 77.0 | 135 | 28.1 |
Seventh survey | 429 | 68.9 | 133 | 31.0 |
Cumulative number of participants | 2691 | Â | 563 | Â |
| Â | Mean | SD | Â | Â |
Follow-up period (y) | 6.9 | 2.1 | Â | Â |
Number of follow-up survey participation (range: 1–4) | 3.4 | 1.0 |  |  |