eTable 1. Response according to study arm, n (%).
| Written | Telephone | Total | |
| Initial sample | 10 166 (100.0) | 14 992 (100.0) | 25 158 (100.0) |
| Evaluable questionnaires after data validation | 3289 (32.3) | 5978 (48.6) | 9267 (36.8) |
| Non-evaluable questionnaires after data validation | 20 (0.2) | 0 (0.0) | 20 (0.1) |
| Response status unknown | 5825 (57.3) | 1 (0.0) | 5826 (23.2) |
| Neutral non-responses | 783 (7.7) | 1439 (9.6) | 2222 (8.8) |
| – Target person unknown | 764 (7.5) | 227 (1.5) | 991 (3.9) |
| – Telephone number invalid | – | 908 (6.1) | 908 (3.6) |
| – Target person does not speak sufficient German | 8 (0.1) | 145 (1.0) | 153 (0.6) |
| – Target person not in the target group | 6 (0.1) | 140 (0.9) | 146 (0.6) |
| – Target person deceased | 5 (0.0) | 19 (0.1) | 24 (0.1) |
| Systematic non-responses | 249 (2.5) | 7574 (50.6) | 7823 (31.1) |
| – Declined | 119 (1.2) | 3790 (25.3) | 3909 (15.5) |
| – Not available | 118 (1.2) | 2812 (18.8) | 2930 (11.6) |
| – Health problems | 5 (0.0) | 68 (0.5) | 73 (0.3) |
| – Target person wishes to respond* | 7 (0.1) | 904 (6.0) | 911 (3.7) |
*The target person wishes to complete the written questionnaire and send it by post, or complete it online or in a telephone interview