The study sample of eligible participants, responders and non-responders by area, sex and mean age in the Telemark study and the follow-up study
| Study population | Outside Grenland (rural) | Grenland (urban) | p Value | Men | Women | p Value | Mean age | Total | |
|---|---|---|---|---|---|---|---|---|---|
| Initial study sample | N | 18 357 | 31 643 | 25 545 | 24 455 | 34.3 | 50 000 | ||
| Eligible | N (%) | 17 691 (96.4) | 30 451 (96.2) | 0.432 | 24 498 (95.9) | 23 644 (96.7) | <0.001 | 34.4 | 48 142 (96.3) |
| Non-responders, total | N (%) | 11 887 (67.2) | 20 156 (66.2) | 0.025 | 17 311 (70.7) | 14 732 (62.3) | <0.001 | 33.6 | 32 043 (66.6) |
| Responders, total | N (%) | 5 804 (32.8) | 10 295 (33.8) | 7 191 (29.3) | 8 908 (37.7) | 36.0 | 16 099 (33.4) | ||
| Responders by 1st questionnaire | N (%*) | 3 645 (62.8) | 6 359 (61.8) | 0.226 | 4 337 (60.3) | 5 667 (63.6) | <0.001 | 36.4 | 10 004 (62.1) |
| Responders by 1st reminder | N (%*) | 1 085 (18.7) | 2 038 (19.8) | 1 411 (19.6) | 1 712 (19.2) | 35.2 | 3 123 (19.4) | ||
| Responders by 2nd reminder | N (%*) | 1 074 (18.5) | 1 898 (18.4) | 1 439 (20.0) | 1 533 (17.2) | 35.2 | 2 972 (18.5) | ||
| Sample of non-responders | N (%†) | 261 (2.2) | 439 (2.2) | 0.938 | 364 (2.1) | 336 (2.3) | 0.277 | 33.3 | 700 (2.2) |
| Agreed to participate | N (%‡) | 104 (38.9) | 156 (35.5) | 0.259 | 136 (37.4) | 124 (36.9) | 0.938 | 34.5 | 260 (37.1) |
| Answered by phone | N (%) | 76 (73.1) | 118 (75.6) | 0.664 | 111 (81.6) | 83 (66.9) | 0.007 | 35.2 | 194 (74.6) |
| Answered by post | N (%) | 28 (26.9) | 38 (24.4) | 25 (18.4) | 41 (33.1) | 32.0 | 66 (25.4) |
Bold typeface represents p values less than 0.05.
*Percentage of Responders, total.
†Percentage of Non-responders, total.
‡Percentage of Sample of non-responders.