The Danish Symptom Cohort: Questionnaire and Feasibility in the Nationwide Study on Symptom Experience and Healthcare-Seeking among 100 000 Individuals
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) (%)
