Reasons for nonparticipation among eligible case and control subjects
| Case subjects | Control subjects | |
|---|---|---|
| Total eligible | 779 | 2,129 |
| Transferred to another clinic | 21 (2.7) | |
| Too ill because of concomitant disease | 15 (1.9) | 21 (0.90) |
| Unreliable interview | 3 (0.4) | 1 (0.04) |
| No permission of physician | 2 (0.3) | |
| Dementia | 64 (8.2) | 7 (0.30) |
| Refusal | 55 (7.1) | 187 (8.80) |
| Missed medical records | 22 (2.8) | |
| Failure to establish contact | 74 (9.4) | 129 (6.00) |
| No monitor available | 17 (2.2) | 1 (0.04) |
| Erroneous exclusions | 33 (4.2) | |
| Deceased; no interview | 11 (1.4) | 2 (0.09) |
| Case and control subjects providing information | 462 (59) | 1,781 (84) |
Data are n (%).