Table 3.
Results from the four waves.
| Wave 1 | Wave 2 | Wave 3 | Wave 4 | Total | |
|---|---|---|---|---|---|
| Invited for participation | 25 000 | 25 000 | 25 000 | 25 000 | 100 000 |
| Men (%) | 12 203 (48.8) | 12 180 (48.7) | 12 348 (49.4) | 12 179 (48.7) | 48 910 (48.9) |
| Women (%) | 12 797 (51.2) | 12 820 (51.3) | 12 652 (50.6) | 12 821 (51.3) | 51 090 (51.1) |
|
| |||||
| Dead (%) | 25 (0.1) | 78 (0.3) | 85 (0.3) | 127 (0.5) | 315 (0.3) |
| Addresses unknown (%) | 247 (1.0) | 252 (1.0) | 236 (0.9) | 226 (0.9) | 961 (1.0) |
| Suffering from severe illness (including dementia) (%) | 556 (2.2) | 480 (1.9) | 468 (1.9) | 468 (1.9) | 1 972 (2.0) |
| Language problems (%) | 233 (0.9) | 228 (0.9) | 195 (0.8) | 229 (0.9) | 885 (0.8) |
| Moved abroad (%) | 53 (0.2) | 172 (0.7) | 188 (0.8) | 201 (0.8) | 614 (0.6) |
| Excluded (% of invited) | 1 114 (4.5) | 1 210 (4.8) | 1 172 (4.7) | 1 251 (5.0) | 4 747 (4.7) |
|
| |||||
| Eligible for the study (% of invited) | 23 886 (95.5) | 23 790 (95.2) | 23 828 (95.3) | 23 749 (95.0) | 95 253 (95.3) |
| Respondents (%) | 12 361 (51.7) | 12 763 (53.6) | 12 298 (51.6) | 12 284 (51.7) | 49 706 (52.2) |
| Men (%) | 5 718 (46.3) | 5 911 (46.3) | 5 815 (47.3) | 5 796 (47.2) | 23 240 (46.8) |
| Women (%) | 6 643 (53.7) | 6 852 (53.7) | 6 483 (52.7) | 6 488 (52.8) | 26 466 (53.3) |
| Median age (IQR) | 52 (40–64) | 52 (40–64) | 52 (40–64) | 52 (39–64) | 52 (40–64) |
|
| |||||
| Completed by telephone interview (% of respondents) | 342 (2.8) | 308 (2.4) | 286 (2.3) | 272 (2.2) | 1 208 (2.4) |
| Men (%) | 129 (37.7) | 110 (35.7) | 93 (32.5) | 106 (39.0) | 438 (36.3) |
| Women (%) | 213 (62.3) | 198 (64.3) | 193 (67.5) | 166 (61.0) | 770 (63.7) |
| Median age (IQR) | 74 (67–79) | 74 (68–96) | 73 (68–80) | 74 (68–94) | 74 (68–96) |
|
| |||||
| Completed after initial letter (% of respondents, cumulative) | 6 437 (26.9) | 7 583 (31.9) | 7 559 (31.7) | 7 353 (31.0) | 28 932 (30.4) |
| Completed after reminder letter (% of respondents, cumulative) | 3 925 (43.4) | 3 130 (45.0) | 2 713 (43.1) | 2 908 (43.2) | 12 676 (43.7) |
| Completed after telephone reminder (% of respondents, cumulative) | 1 999 (51.7) | 2 050 (53.6) | 2 026 (51.6) | 2 023 (51.7) | 8 098 (52.2) |
|
| |||||
| Nonrespondents (% of eligible) | 11 525 (48.3) | 11 027 (46.4) | 11 530 (48.4) | 11 465 (48.3) | 45 547 (47.8) |
| Not wishing to participate (indicated by telephone/email or postal contact) (%) | 6 880 (28.8) | 6 287 (26.4) | 6 407 (26.9) | 6 116 (25.8) | 25 690 (27.0) |
| Indicated “other reasons” for nonparticipation (%) | 11 (0.04) | 85 (0.4) | 99 (0.4) | 123 (0.5) | 318 (0.3) |
| Nonrespondents (no achieved contact in the reminder procedure) (%) | 4 634 (19.4) | 4 655 (19.6) | 5 024 (21.1) | 5 226 (22.0) | 19 539 (20.5) |