Factors associated with attrition in a longitudinal online study: results from the HaBIDS panel

Background Knowing about predictors of attrition in a panel is important to initiate early measures against loss of participants. We investigated attrition in both early and late phase of an online panel with special focus on preferences regarding mode of participation. Methods We used data from the HaBIDS panel that was designed to investigate knowledge, attitudes, and practice regarding infections in the German general population. HaBIDS was divided into two phases: an initial phase when some participants could choose their preferred mode of participation (paper-and-pencil or online) and an extended phase when participants were asked to become members of an online panel that was not limited regarding its duration (i.e. participants initially preferring paper questionnaires switched to online participation). Using competing risks regression, we investigated two types of attrition (formal withdrawal and discontinuation without withdrawal) among online participants, separately for both phases. As potential predictors of attrition, we considered sociodemographic characteristics, physical and mental health as well as auxiliary information describing the survey process, and, in the extended phase, initial mode preference. Results In the initial phase, higher age and less frequent Internet usage predicted withdrawal, while younger age, higher stress levels, delay in returning the consent form, and need for receiving reminder emails predicted discontinuation. In the extended phase, only need for receiving reminder emails predicted discontinuation. Numbers of withdrawal in the extended phase were too small for analysis. Initial mode preference did not predict attrition in the extended phase. Besides age, there was no evidence of differential attrition by sociodemographic factors in any phase. Conclusions Predictors of attrition were similar in both phases of the panel, but they differed by type of attrition (withdrawal vs. discontinuation). Sociodemographic characteristics only played a minor role for both types of attrition. Need for receiving a reminder was the strongest predictor of discontinuation in any phase, but no predictor of withdrawal. We found predictors of attrition, which can be identified already in the early phase of a panel so that countermeasures (e.g. special incentives) can be taken. Electronic supplementary material The online version of this article (10.1186/s12874-017-0408-3) contains supplementary material, which is available to authorized users.

A: Frequency of infections and infection-associated symptoms in the last 12 months

1: General information
First of all, we need two details about you, so that we can adapt the following questions for you.
[age] How old are you? enter your answer here [sex] What is your gender? □ Male □ Female

2: Infections
In the following section we ask you to estimate how often you have had the following infections in the past 12 months. If, for example, you have had three colds and one otitis media, then you have had a total of four infectious events of the upper respiratory tract (thus "3 to 4 times" the fever lasted longer than 1 day, please count as a one-time event; e.g. fever for 7 days = "once" ** Diarrhea is at least 3 times fluid / pulpy bowel movements within 24 hours. If the diarrhea lasted longer than 1 day, please count as a one-time event; e.g. diarrhea for 4 days = "once"

2: General information
The following information helps to evaluate the results of the HaBIDS surveys. We use this information to investigate whether differences between participants are caused by certain demographic factors, such as gender or age. We do not evaluate the data for your person, but for those groups to which you can, for example, be assigned according to your age group, your gender or your school leaving certificate.
[sex] What is your gender? [marital] What is your marital status? "Married", "divorced" and "widowed" also refers to a registered life partnership. □ Single □ Married □ Divorced □ Widowed

3: Education and profession
[SES1] What is your highest general education? □ Pupil, attend a full-time school □ Left elementary school without school leaving certificate □ Elementary school (German "Hauptschule") □ Secondary school / high school (German "Realschule") □ Polytechnic high school of the GDR with completion of the 8th or 9th class □ Polytechnic high school of the GDR with completion of the 10th class □ "Fachhochschulreife", completion of a subject-specific high school □ General or subject-specific university entrance qualification / "Abitur" (German "Gymnasium" / "EOS") □ Another school leaving certificate, namely: [SES1a] Which school leaving certificate do you strive for? ▼ SES1 == "Pupil" □ Elementary school (German "Hauptschule") □ Secondary school / high school (German "Realschule") □ "Fachhochschulreife", completion of a subject-specific high school □ General or subject-specific university entrance qualification / "Abitur" □ Another school leaving certificate, namely: [SES2] What is your highest level of qualification? □ Still in vocational training (vocational preparation year, trainee, intern, student) □ Pupil and attend a vocational-oriented or technical school or similar □ No vocational qualification and not in vocational training □ Completed apprenticeship □ Training at vocational school, commercial school, or middle service public administration □ Training at a GDR technical school □ Training at a technical school, vocational academy or technical academy □ Bachelor of a university (of applied sciences) □ Degree of a university of applied sciences (z. B. Diplom, Master) □ University degree (z. B. Diplom, Magister, Staatsexamen, Master) □ Doctorate □ Don't know □ Another professional qualification, namely: [SES3] What is the average monthly net income of your household as a whole? This household includes all persons who live and work together here. The average monthly net income of your household is the sum of wages, salaries, income from self-employed activities (average net operations, i.e. minus operating expenses and taxes), or pension. Please also include the income from public aid, income from renting and leasing, property, housing, child allowance and other income, and then deduct taxes and social insurance contributions. □ Less than 1250 Euros □ 1250 to less than 1750 Euros □ 1750 to less than 2250 Euros □ 2250 to less than 3000 Euros □ 3000 to less than 4000 Euros □ 4000 to less than 5000 Euros □ 5000 and more □ I don't want to answer □ Don't know [Internetnutzung] How often do you personally use the Internet for private purposes? ▼ Internet == "Yes" □ Daily / almost daily □ About two or three times a week □ About once a week □ About two or three times a month □ About once a month □ Less than once a month □ I don't use the Internet at home, but there is an access

C (mixed-mode) / D (online-only): Prevention measures against respiratory infections
The following questions are about how to protect yourself from respiratory infections.

C (online-only): Determinants for participation in community-based cohorts on infectious diseases
We plan to conduct a scientific study in which the transmission and risks of gastrointestinal and respiratory diseases such as colds are to be investigated using new methods. The results are supposed to lead to the development of better protective measures. Thus, you will also benefit in the future.
To prepare for this study, we would like to know the circumstances under which you would be generally willing to participate in such a study. Your responses help us to design the study in a way that best suits the needs of future participants. Your opinion is important to us. If you complete this questionnaire, it does not mean that you must participate in the planned study or be invited to do so.
The following questions deal with the conditions under which you would participate in such a study.

1: Report on disease signs
[Nino1] If you should report daily on the onset of disease signs such as cough or diarrhea, would you be willing to do that for over 2 years? □ Yes, I would do it for 2 years □ Not at all □ I would do it for the following duration at maximum (please enter number of months): [Nino2] If you should report weekly on the onset of disease signs such as cough or diarrhea, would you be willing to do that for over 2 years? □ Yes, I would do it for 2 years □ Not at all □ I would do it for the following duration at maximum (please enter number of months): [Nino3] If you should report monthly on the onset of disease signs such as cough or diarrhea, would you be willing to do that for over 2 years? □ Yes, I would do it for 2 years □ Not at all □ I would do it for the following duration at maximum (please enter number of months):

2: Report on disease signs (continued)
[Nino4] How would you like to regularly report the symptoms like cough or diarrhea in the following way?

4: Biological samples
[Nino6] Would you be willing to take a smear from the nasal cavity in a respiratory disease with a cotton pad and send it to us? The material is provided by us. Shipping is free of charge for you. □ Yes □ No □ Yes, but only on the condition that (please specify): [Nino7] Would you be willing to send us a stool sample in the case of diarrhea, which you can take according to a manual? The material is provided by us. Shipping is free of charge for you. □ Yes □ No □ Yes, but only on the condition that (please specify):  [6] The data from the study should not be used commercially. □ □ □ [7] I would participate in the study, independently of the specific data protection procedure, as long as this was supported by the responsible data protection officer. □ □ □

5: Data protection
[8] I would not want to participate in any of the above circumstances. □ □ □ [Nino8_other] I would insist in another data protection measure not mentioned here, namely: enter your answer here

6: Motivation
If the study were to be introduced in your neighborhood, how important would you consider the following aspects to motivate people to participate in such a scientific study? Please estimate whether the measures below are more beneficial, unimportant, or more hindering to motivate people to participate.
[Nino9a] Support of the study by certain persons / institutions: More beneficial Unimportant More hindering [1] [9] There is the possibility of submitting research questions themselves. □ □ □ [10] If the results of the study can contribute directly to reducing the incidence of infections in their own environment. □ □ □ [11] If the participants are recognizable as researchers of the project (for example, listed on a website on request, or, if desired, mentioned in scientific publications).

7: Percentage of participation
[Nino10] We have mentioned above various ways to conduct the study. Please estimate, which percentage of the population in your community would participate in such a study, if… I estimate that ... percent of the population would participate [1] ... the effort would be very limited (short duration (6 months), simple and rare inquiries (monthly), no sampling in case of respiratory disease or diarrhea): Please specify an estimate between 0% and 100%. [2] ... the effort would be relatively high (long duration (2 to 3 years), frequent inquiries (daily) with more than 3 samples per half-year): Please specify an estimate between 0% and 100%. [3] ... maximum anonymity would be ensured, i.e. no location recording: Please specify an estimate between 0% and 100%. [4] ... the research institute could assign my identity to the data but would not pass it on to other persons or institutions: Please specify an estimate between 0% and 100%.

8: Acceptance of blood sampling
[Nino11] Some research questions can only be carried out by the examination of blood. Under which circumstances would you agree? Yes, agreed

Partly, partly
No, not agreed [1] Only once at the beginning and at the end of the study □ □ □ [2] Only in the case of blood collection by a doctor of my trust □ □ □ [3] In the case of blood sampling in a study center by medical staff □ □ □ [4] By myself, by a special device, apply a bloodstripe from my fingertip to special paper and send it □ □ □ [5] In the case of blood sampling by medical staff who come to my home □ □ □

9: Study center
[Nino12] Some studies require detailed medical examinations and surveys in a study center. If the study center was nearby, would you be willing to participate in an investigation program lasting 6 hours? □ Yes □ Not at all □ I would do it for the following duration at maximum (please enter duration in hours): [Nino12a] What day of the week and what time would you prefer to visit the study center? You can specify several days. Please enter "0" if the weekday is not possible for you. ▼ Nino12 != "Not at all" [1]  [hhkinder] Do minor children live in your household? ▼ hh != "I live alone in the household" □ Yes □ No [hhage_pt] How old are the members of your household (including yourself)? Please start with the youngest member. For children under one year, please enter "0". ▼ hh != "I live alone in the household" [1] Age (in years) [2] Age (in years) [3] Age (in years) [4] Age (in years) [5] Age (in years) [6] Age (in years) [7] Age (in years) [8] Age (in years) [9] Age (in years) [10] Age (in years)

D (mixed-mode): Social contact patterns (summer)
This questionnaire is about how many people you have contact with in one day.
Contact means that you have spoken with one person more than 10 words and were not more than 2 meters away from that person. Shaking hands or kissing is also counted as contact (i.e. whenever you touch a person's skin).
You can start the survey only once. You can now enter the contacts for yesterday, or wait until tomorrow and fill in the contacts retrospectively for today.
Before you complete the questionnaire, please refer to the pdf guide to see how you can enter the contacts. In order to make sure you have not forgotten a contact, we suggest that you try to go through the whole day in your mind. Your appointment book may be useful. Since it can be difficult not to mess with the contacts, we suggest that you first write down all contact persons on paper and then pass the information to the online questionnaire. A table for your notes is included in the pdf guide. You can also take notes during the day and enter your contacts in the evening. Please start with the youngest members. For children under one year, please enter "0". ▼hh_single == "No" [1] Age (in years) [2] Age (in years) [3] Age (in years) [4] Age (in years) [5] Age (in years) [6] Age (in years) [7] Age (in years) [8] Age (in years) [9] Age (in years) [10] Age (in years)

2: Regular contacts in work / education / school
"Contact" means, for example: You spoke to a person and the distance was no more than two meters. Please don't enter any contacts that have been made by telephone only. or You have touched the skin of another person (for example, shaking hands, kissing, contact sports ...).
[Kontakt] Do you regularly have a lot of contact with other people, in other words, more than 10 contacts with customers, pupils, students, colleagues, etc.?
[Kontakt_anz] With how many people (customers, students, patients, etc.) per day do you regularly have lots of contact? Please include the persons who you only meet during work / training or at school. Please don't include these persons in the following questions. There, please enter only the persons you have met (also) private. ▼ Kontakt == "Yes" enter your answer here

3: Interpersonal contacts in leisure time
We would like to ask you to enter all the contacts which have taken place within one day in the following questionnaire. Look for a day, e.g. yesterday. Please refer to a total of 24 hours.
Start with the first person you were in contact with on the day you completed the questionnaire. If you had contact with other persons on the day, answer the question "Did you have contact with further persons on this day?" with "Yes" and click "Next" to add another person. If you have not contacted another person, please answer "No" and click "Next". You will be directed to the end of the survey.
[Datum] Please enter the date of the day for which you complete the questionnaire for your personal contacts. enter your answer here 4: 1st contact person "Contact" means, for example: You spoke to a person and the distance was no more than two meters. Please don't enter any contacts that have been made by telephone only. or You have touched the skin of another person (for example, handing, kissing, contact sports ...).

E: Adult vaccinations
In Germany, an independent body of experts recommends which vaccinations are useful in which age. Most vaccinations are carried out in the early childhood in order to protect children from infections as early as possible. In this questionnaire, however, we are specifically interested in vaccinations in adulthood.

1: Vaccinations
[IM] Have you been vaccinated against the following infections in the last 10 years?
Are you planning to get vaccinated against one or more of the above-mentioned infections?

11: Activities about Ebola
[info] Have you changed your media use since the Ebola outbreak has become public? Yes No I use the Internet more often/in addition to inform myself about Ebola.
□ □ I use television more often/in addition to inform myself about Ebola.
□ □ I use the radio more often/in addition to inform myself about Ebola.
□ □ I use print media more often/in addition to inform myself about Ebola.
□ □ I use information from public institutions (e.g. Robert Koch-Institute, World Health Organization) more often/in addition to inform myself about Ebola.
□ □ [activity] Did you do something among the following list of actions in connection to Ebola? (multiple choice possible) □ Write a letter to the editor or a blog entry about Ebola in a paper or on the Internet □ Write a comment to an article in the Internet (e.g. Tagesschau □ □ … more than 10 persons a day (e.g. students, customers, colleagues)?

G: Tick-borne infections
Some diseases are transmitted by contact with animals, e.g. through stitches of ticks or mosquitoes. This questionnaire is about your experience with ticks.

1: Devices used
First, however, we would like to ask you 3 general questions about which device you use to complete the HaBIDS questionnaires. We can use your answers to optimize the presentation of our questionnaires.
[momentan] Which device have you used most frequently to fill the questionnaires of the HaBIDS study?

H: Antibiotics
In this part of the questionnaire, we ask you about antibiotics. Antibiotics are drugs that can slow down or kill pathogens in their growth. Infections are caused by pathogens and are often associated with fever. In Germany antibiotics must be prescribed by a doctor.

I: Social contact patterns (winter)
This questionnaire is about how many people you have contact with in one day.
Contact means that you have spoken with one person more than 10 words and were not more than 2 meters away from that person. Shaking hands or kissing is also counted (i.e., whenever you touch a person's skin). You can fill in the contacts for yesterday, or wait until tomorrow and fill in the contacts retrospectively for today.
If you have a lot of contact with other people, that is, more than 10 contacts with customers, pupils, students, colleagues, etc., you don't need to list these professional contacts individually.
To make sure that you don't forget any contact outside of work / education / school, we suggest that you try to keep your records in mind all day. Your appointment book may be useful. Since it can be difficult not to mess with the contacts, we suggest that you first write down all contact persons on paper and then pass the information. You can also take notes during the day and enter your contacts in the evening.

1: Regular contacts in work / education / school
"Contact" means, for example: You spoke to a person and the distance was no more than two meters.
If you don't enter anything in the last column, we assume that you have only one person with these properties.
[weiter] Click "Next" to start entering your contacts. If you don't want to continue this survey, please let us know: □ I don't want to continue the survey. 70

3: Interpersonal contacts in leisure time
We would like to ask you to enter all the contacts which have taken place within one day in the following questionnaire. Look out day, e.g. yesterday. Please refer to a total of 24 hours.
[Datum] Please specify the date of the day for which you complete the questionnaire for your personal contacts. enter your answer here   [P2_hh_age1] How old are the member of your household (including yourself)? Please start with the youngest member. For children under one year, please enter "0". ▼ P2_hh_single == "No" [1] Age (in years) [2] Age (in years) [3] Age (in years) [4] Age (in years) [5] Age (in years) [6] Age (in years) [7] Age (in years) [8] Age (in years) [9] Age (in years) [10] Age (in years) [GR_12] Are there among those household members people who are particularly vulnerable to flu, e.g. elderly or chronically ill persons? ▼ P2_hh_single == "No" □ No □ I am not sure □ Yes, number of persons: (multiple choice possible) ▼ (GR_1 == "Yes") & (GR_13 == "Yes") □ In my household, one or more people were ill within two weeks before myself. □ In my household, one or more people were ill within two weeks after myself. □ In my household, one or more people were ill with me at the same time. □ In my household, one or more people were ill at another time, that is, not within 2 weeks before or after my own illness. □ I don't know when the other person(s) in my household was ill.

7: Influenza vaccination II
[GR_24] Did anyone give you the advice or recommendation to get vaccinated against influenza? □ Yes □ No □ Don't know [GR_25] Who gave you the advice or recommendation to get vaccinated against flu? (multiple choice possible) ▼ GR_24 == "Yes" □ General practioner □ Gynecologist □ Pediatrician □ Family □ Someone else, namely: [GR_26] Was the fact that someone gave you the advice or recommendation to get vaccinated against influenza very important for your decision to get vaccinated? ▼ (GR_17 == "Yes") & (GR_24 == "Yes") □ Yes

10: Statements about influenza vaccination
How do you assess the following two statements?
[GR_36] The information about the influenza vaccination, which I receive through the media, allows me to make a decision on whether to vaccinate myself or not. □ Applies □ Rather applies □ Does rather not apply □ Does not apply □ I have not received any such information through the media.
[GR_37] The information about the influenza vaccination, which I receive through the media, is clear to me. □ Applies □ Rather applies □ Does rather not apply □ Does not apply □ I have not received any such information through the media.

K: Sexual contact patterns & medical history
The risk of getting an infection may be related to whether or not you are suffering from another condition. In the following, we are therefore interested in diseases which are not infections. These include e.g. sugar disease, heart attack or allergies.

1: Information about yourself and general health
For the analysis of this survey, it is very important that we analyse the questions separately by gender and age group. The frequency and severity of many diseases differs depending on gender or age. Unfortunately, not all participants have entered gender and age. We would therefore ask you to enter these two details here (regardless of whether you have already made this information).
[ [ANAM_23] When did cancer of the lung occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_1 == "Yes" OR ANAM_22_m_1 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_24] Are you currently in medical treatment because of cancer of the lung? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_1 == "Yes" OR ANAM_22_m_1 == "Yes") □ Yes [ANAM_41] When did black skin cancer occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_10 == "Yes" OR ANAM_22_m_10 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_42] Are you currently in medical treatment because of black skin cancer? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_10 == "Yes" OR ANAM_22_m_10 == "Yes") □ Yes □ No [ANAM_43] When did cancer of the pancreas occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_11 == "Yes" OR ANAM_22_m_11 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_44] Are you currently in medical treatment because of cancer of the pancreas? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_11 == "Yes" OR ANAM_22_m_11 == "Yes") □ Yes □ No [ANAM_45] When did cancer of the stomach occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_12 == "Yes" OR ANAM_22_m_12 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_46] Are you currently in medical treatment because of cancer of the stomach? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_12 == "Yes" OR ANAM_22_m_12 == "Yes") □ Yes □ No [ANAM_47] When did cancer of the kidney and urinary tract occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_13 == "Yes" OR ANAM_22_m_13 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_48] Are you currently in medical treatment because of cancer of the kidney and urinary tract? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_13 == "Yes" OR ANAM_22_m_13 == "Yes") □ Yes □ No [ANAM_49] When did cancer of the mouth and throat occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_14 == "Yes" OR ANAM_22_m_14 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_50] Are you currently in medical treatment because of cancer of the mouth and throat? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_14 == "Yes" OR ANAM_22_m_14 == "Yes") □ Yes □ No [ANAM_51] When did non-Hodgkin lymphoma occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_15 == "Yes" OR ANAM_22_m_15 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_52] Are you currently in medical treatment because of non-Hodgkin lymphoma? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_15 == "Yes" OR ANAM_22_m_15 == "Yes") □ Yes □ No [ANAM_53] When did Hodgkin's disease occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_16 == "Yes" OR ANAM_22_m_16 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_54] Are you currently in medical treatment because of Hodgkin's disease? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_16 == "Yes" OR ANAM_22_m_16 == "Yes") □ Yes □ No [ANAM_55] When did leukemia occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_17 == "Yes" OR ANAM_22_m_17 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_56] Are you currently in medical treatment because of leukemia? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_17 == "Yes" OR ANAM_22_m_17 == "Yes") □ Yes □ No [ANAM_57] When did cancer of the liver occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_18 == "Yes" OR ANAM_22_m_18 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_58] Are you currently in medical treatment because of cancer of the liver? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_18 == "Yes" OR ANAM_22_m_18 == "Yes") □ Yes □ No [ANAM_59] When did cancer of the esophagus occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_19 == "Yes" OR ANAM_22_m_19 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_60] Are you currently in medical treatment because of cancer of the esophagus? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_19 == "Yes" OR ANAM_22_m_19 == "Yes") □ Yes □ No [ANAM_61] When did cancer of the brain occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_20 == "Yes" OR ANAM_22_m_20 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_62] Are you currently in medical treatment because of cancer of the brain? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_20 == "Yes" OR ANAM_22_m_20 == "Yes") □ Yes □ No [ANAM_63] When did cancer of the thyroid occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_21 == "Yes" OR ANAM_22_m_21 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_64] Are you currently in medical treatment because of cancer of the thyroid? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_21 == "Yes" OR ANAM_22_m_21 == "Yes") □ Yes □ No [ANAM_65] When did cancer of the bones occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_22 == "Yes" OR ANAM_22_m_22 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_66] Are you currently in medical treatment because of cancer of the bones? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_22 == "Yes" OR ANAM_22_m_22 == "Yes") □ Yes □ No [ANAM_67] When did cancer of the larynx occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_23 == "Yes" OR ANAM_22_m_23 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_68] Are you currently in medical treatment because of cancer of the larynx? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_23 == "Yes" OR ANAM_22_m_23 == "Yes") □ Yes □ No [ANAM_69] When did cancer of the gallbladder occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_24 == "Yes" OR ANAM_22_m_24 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_70] Are you currently in medical treatment because of cancer of the gallbladder? ▼ (ANAM_4_2 == "Yes") AND (ANAM_22_f_24 == "Yes" OR ANAM_22_m_24 == "Yes") □ Yes □ No [ANAM_71] When did {ANAM_22_f_other}{ANAM_22_m_other} occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_2 == "Yes") AND ( ! (is_empty(ANAM_22_f_other)) OR ( ! (is_empty(ANAM_22_m_other)) Age: enter your answer here Year: enter your answer here [ANAM_72] Are you currently in medical treatment because of {ANAM_22_f_other}{ANAM_22_m_other}? ▼ (ANAM_4_2 == "Yes") AND ( ! (is_empty(ANAM_22_f_other)) OR ( ! (is_empty(ANAM_22_m_other)) □ Yes □ No

5: Metabolic diseases
[ANAM_73] Which metabolic disease is / was it? (multiple choice possible) ▼ ANAM_4_3 == "Yes" □ Sugar disease or diabetes mellitus □ Increased blood lipids or cholesterol or triglycerides □ Gout or a uric acid disease □ Hyperfunction of the thyroid gland (hyperthyroidism) □ Underactive thyroid (hypothyroidism) □ Others, namely: [ANAM_74] When did diabetes occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_1 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_75] Have you been diagnosed with diabetes for the first time during pregnancy? ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_1 == "Yes") AND (sex_ON11 == "2") □ Yes □ No □ Don't know [ANAM_76] How are you currently being treated? Please also think of injected insulin and insulin pumps. ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_1 == "Yes") □ Only with insulin □ Only with tablets □ With insulin and tablets □ Only dietary □ No treatment □ Don't know □ Others, namely: [ANAM_77] How long have you been treated? Please indicate either your age at the beginning of the treatment or the year of commencement of treatment, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_1 == "Yes") AND (ANAM_76 != "No treatment") Age: enter your answer here Year: enter your answer here [ANAM_78] When did increased blood lipids occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_2 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_79] Are you currently in medical treatment because of increased blood lipids? ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_2 == "Yes") □ Yes □ No [ANAM_80] When did gout occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_3 == "Yes") Age: enter your answer here Year: enter your answer here [ANAM_81] Are you currently in medical treatment because of gout? ▼ (ANAM_4_3 == "Yes") AND (ANAM_73_3 == "Yes") □ Yes □ No [ANAM_82] When did {if(ANAM_73_4 == "Yes", "hyperthyroidism", "hypothyroidism")} occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND ((ANAM_73_4 == "Yes") OR (ANAM_73_5 == "Yes")) Age: enter your answer here Year: enter your answer here [ANAM_83] How are you currently being treated? ▼ (ANAM_4_3 == "Yes") AND ((ANAM_73_4 == "Yes") OR (ANAM_73_5 == "Yes")) □ Thyroid hormones □ Radioiodine therapy □ Irradiation in the neck area □ Thyroid surgery □ Iodine tablets □ No treatment □ Don't know □ Others, namely: [ANAM_84] How long have you been treated? Please indicate either your age at the beginning of the treatment or the year of commencement of treatment, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND ((ANAM_73_4 == "Yes") OR (ANAM_73_5 == "Yes")) AND (ANAM_83 != "No treatment") Age: enter your answer here Year: enter your answer here [ANAM_85] When did {ANAM_73_other} occur for the first time? Please indicate your age at the time of the first diagnosis or the year of the first diagnosis, whichever you remember better. ▼ (ANAM_4_3 == "Yes") AND ( ! (is_empty (ANAM_73_other)

18: Sexual contacts
In the following, we are now asking for sexual contacts, that is, those with whom sexual intercourse has taken place. There are diseases that can be transmitted via sexual intercourse. The transmission takes place only sometimes and not everyone is affected. We ask these questions to understand the possible spread of these pathogens. This is not about whether someone was or is ill. It is also very important to get answers from people who don't have sexually transmitted diseases. Again, we would like to stress at this point that your answers will remain anonymous and no individual responses will be visible. The answer to the questions is, of course, voluntary.
[keine_Antwort] If you don't want to complete this section of the survey, please let us know.
In the course of the survey you have also the option "I don't want to answer". □ I don't want to complete this section of the survey.
[sex1] How old were you when you first had sexual intercourse? If you are not sure how old you were, please give an estimate. ▼ keine_Antwort_1 != "Yes" □ I don't want to answer. □ I have not had any sexual contact yet. □ My age in years was then: [sex2] Do you currently have a sexual partnership? Sexual partnership means: a partnership in which sexual intercourse takes place. ▼ (keine_Antwort_1 != "Yes") & (sex1 != "I have not had any sexual contact yet.") □ Yes □ No □ I don't want to answer.
[sex2_dauer] Do you think that this sexual partnership will continue in 3 months? ▼ sex2 == "Yes" □ Yes □ No □ Don't know □ I don't want to answer.

19: Contacts with persons of the opposite sex
[sex3] If you think about your whole life, with how many people of the opposite sex have you had sexual intercourse so far? enter your answer here □ I don't want to answer.
[sex4] If you think about the last 12 months (since June 1, 2014), with how many people of the opposite sex did you have sexual intercourse? ▼ sex3_1_anz >= "1" enter your answer here □ I don't want to answer.
[sex4neu] How many of these {sex4_1_anz} people you have had sexual intercourse with over the past 12 months have been new partners with whom you have had sexual intercourse for the first time? ▼ sex4_1_anz >= "1" enter your answer here □ I don't want to answer. 20: Contacts with persons of the same sex [sex5] If you think about your entire life, with how many people of the same sex have you had sexual intercourse so far? enter your answer here □ I don't want to answer.
[sex6] If you think about the last 12 months (since June 1, 2014), with how many people of the same sex did you have sexual intercourse? ▼ sex5_1_anz >= "1" enter your answer here □ I don't want to answer.
[sex6neu] How many of these {sex6_1_anz} people you have had sexual intercourse with over the last 12 months have been new partners with whom you had sexual intercourse for the first time? ▼ sex6_1_anz >= "1" enter your answer here □ I don't want to answer.

21: Age of contact persons
[sex7_99] How old were the last partners with whom you had sexual intercourse? Please refer only to your sexual partners during the last 12 months (since June 1, 2014). Please also provide details of how often you / your partner used condoms when having sexual intercourse. □ I don't want to answer.

L: Ebola risk perception (follow-up)
In November 2014, we asked you what you think about the Ebola outbreak in West Africa and whether / how Ebola affects your everyday life. We would now like to examine whether these aspects have changed over time. That is why we ask you a few questions from November, some of them in changed form.

M: Tick-borne infections (follow-up)
In July 2014 we interviewed you about ticks and tick infections. Here we could get interesting results. We would like to ask you more about this topic in order to be able to interpret them more precisely. You already know some of the questions from the first questionnaire on this topic. Nevertheless, please answer all questions in this questionnaire. [ZE_2_14] How did you remove the tick? (If you have been bitten more than once, please refer to the last time you were bitten.) ▼ ZE_2_12 == "Yes" □ I myself removed the tick (within 1 hour) after the discovery / had it removed by a person (not medically trained). □ I myself removed the tick, but not immediately (more than an hour after the discovery) / had it removed by a person (not medically trained). □ I visited a doctor to have the tick removed.

6: Last time doctor
[ZE_2_17] Please remember the last time that you have visited a doctor because you were bitten by a tick or suspected a tick bite: What was the main reason for visiting the doctor? ▼ ZE_2_15 == "Yes" □ I wanted to have the tick removed. □ I was unsure about having the tick properly removed. □ I was afraid of being infected with borreliosis. □ I was afraid of being infected with early summer meningoencephalitis (TBE). □ I felt ill without being able to say exactly why. □ Another reason, namely: [ZE_2_18] Were there other reasons to visit the doctor, besides the above mentioned reason? (multiple choice possible) ▼ ZE_2_15 == "Yes" □ No, there were no other reasons. □ I wanted to have the tick removed. □ I was unsure about having the tick properly removed. □ I was afraid of being infected with borreliosis. □ I was afraid of being infected with early summer meningoencephalitis (TBE). □ I felt ill without being able to say exactly why.

7: Suspicion of borreliosis
[ZE_2_19] Did you have any symptoms of the disease that let you suspect to be infected with borreliosis? ▼ (ZE_2_17 == "I was afraid of being infected with borreliosis.") OR (ZE_2_18 == "I was afraid of being infected with borreliosis.") □ Yes □ No [ZE_2_20] What were the symptoms? (multiple choice possible) ▼ ZE_2_19 == "Yes" □ Erythema migrans: redness of the skin around the puncture site that has migrated over time □ Fever □ Fatigue □ Headache □ Swollen lymph nodes □ Burning pain □ Paralysis □ Numbness on the skin □ Visual or hearing impairment □ Arrhythmia □ Joint pain □ Other: [ZE_2_21] Has your suspicion of borreliosis been confirmed by a doctor? ▼ (ZE_2_17 == "I was afraid of being infected with borreliosis.") OR (ZE_2_18 == "I was afraid of being infected with borreliosis.") □ Yes □ No

8: Diagnosis of borreliosis
In the previous questions, we asked if had a suspicion of borreliosis. In the following questions, we are concerned with the question of whether borreliosis has ever been diagnosed and how this diagnosis came about. The questions are therefore similar to the previous questions. Please answer the following questions anyway.
[ZE_2_22] Have you ever been diagnosed with borreliosis? □ Yes □ No [ZE_2_23] When was borreliosis diagnosed? ▼ ZE_2_22 == "Yes" □ Immediately after a tick bite □ Within 4 weeks after ticking □ After more than 4 weeks after the tick bite □ I could not remember the tick bite.
[ZE_2_24] What symptoms have you had in relation to the diagnosed borreliosis? (multiple choice possible) ▼ ZE_2_22 == "Yes" □ Erythema migrans: redness of the skin around the puncture site that has migrated over time □ Fever □ Fatigue □ Headache □ Swollen lymph nodes □ Burning pain □ Paralysis □ Numbness on the skin □ Visual or hearing impairment □ Arrhythmia □ Joint pain □ Other: [ZE_2_25] Has treatment of borreliosis been performed? ▼ ZE_2_22 == "Yes" □ Yes, I got an antibiotic for 7-14 days. □ Yes, I have had an antibiotic for more than four weeks. □ No, I have not received any antibiotics.

9: Suspicion of TBE
[ZE_2_26] Did you have any symptoms of the disease that let you suspect to be infected with TBE? ▼ (ZE_2_17 == "I was afraid of being infected with early summer meningoencephalitis (TBE).") OR (ZE_2_18 == "I was afraid of being infected with early summer meningoencephalitis (TBE).") □ Yes □ No [ZE_2_27] What were the symptoms? (multiple choice possible) ▼ ZE_2_26 == "Yes" □ Erythema migrans: redness of the skin around the puncture site that has migrated over time □ Fever □ Fatigue □ Headache □ Swollen lymph nodes □ Burning pain □ Paralysis □ Numbness on the skin □ Visual or hearing impairment □ Arrhythmia □ Joint pain □ Other: [ZE_2_28] Has your suspicion of TBE disease been confirmed by a doctor? ▼ (ZE_2_17 == "I was afraid of being infected with early summer meningoencephalitis (TBE).") OR (ZE_2_18 == "I was afraid of being infected with early summer meningoencephalitis (TBE).") □ Yes □ No

N: Multi-drug resistant pathogens
We would like to ask you about multiresistant germs, also known as "hospital germs". By this we mean pathogens which are resistant to various antibiotics. If these germs cause illness, the affected persons must be treated with special antibiotics.

3: Opinion
In the following, we would like to gather your opinion on multiresistent germs.

4: Reasons
In the following, we would like to know what you think contributes to the spread of multiresistant germs.
[MRE14] What do you think is important for the spread of multiresistant germs?

5: Animal breeding
The following questions deal with the topic of animal breeding.
[MRE15] Do you or a person who lives in your household have professional care with farm animals, e.g. as a farmer, veterinarian or in meat processing?

6: Dissemination and responsibility
The following three questions address the issue of the spread of antibiotic resistance and responsibility in the health system.
[MRE20] Everyone is responsible for reducing the spread of multiresistant germs through the correct use of antibiotics.

O: Fair allocation of scarce medical resources
In medicine, medical resources may not be available to all who need them. One example is organ transplantation. Even in the case of a flu pandemic, the vaccine can become scarce. The purpose of this questionnaire is to examine how scarce medical resources should be distributed. In the following questionnaire, there are no "right" or "wrong" answers. We are much more interested in your personal opinion about the distribution of medical resources.

2: Distribution of medical services
Please read the following statements and state the degree of your approval.
[FM_Prinzip] In the distribution of medical resources ( □ □ □ □ □ ... if the general health of the patient (i.e. the medical prognosis) is taken into account.
□ □ □ □ □ 3: Distribution problem (alternative 1) ▼ FM_Szenario == "1" The following situation is invented. However, it shows similarities with processes in reality. In a city, a sexually transmitted disease has spread for 20 years. This disease leads to death within if (FM_Mortalitaet == "1", "15 years", "5 years"). Currently every 50th inhabitant of the city is ill. The inhabitants differ in how often they change sexual partners and how often they have several sexual partners at the same time: approximately every 5th inhabitant belongs to the group with frequently changing partners or several partners at the same time. The remaining 80% of the population rarely change sexual partners. Younger residents of this city are changing their partners more often than older ones. A vaccine is now available for the first time. This protects reliably against contamination, already diseased persons are not cured by the vaccination however. The vaccine stock is currently not sufficient for all residents of the city. The vaccination can be distributed according to different criteria.

3: Distribution problem (alternative 2)
▼ FM_Szenario == "2" The following situation is invented. However, it shows similarities with processes in reality. In a city, a sexually transmitted disease has spread for 20 years. This disease leads to death within if (FM_Mortalitaet == "1", "15 years", "5 years"). Currently every 50th inhabitant of the city is ill. The inhabitants differ in how often they change sexual partners and how often they have several sexual partners at the same time: approximately every 5th inhabitant belongs to the group with frequently changing partners or several partners at the same time. The remaining 80% of the population rarely change sexual partners. Younger residents of this city are changing their partners more often than older ones. A treatment option is now available for the first time. A ill person who is treated can become as old as a healthy person. The treatment protects others from infection. The treatment is very expensive. Therefore, it is not possible to treat all persons who have been infected. The treatment can be distributed according to different criteria.

P: Frequency of infections during the winter season & influenza vaccination (season 2015/16)
In this questionnaire, we are interested in whether you had an infection of the respiratory tract in the past months and whether you were vaccinated against influenza in the autumn / winter season 2015/16.

10: Statements about influenza vaccination
How do you assess the following two statements?
[GR_36] The information about the influenza vaccination, which I receive through the media, allows me to make a decision on whether to vaccinate myself or not. □ Applies □ Rather applies □ I have not received any such information through the media. □ Does rather not apply □ Does not apply [GR_37] The information about the influenza vaccination, which I receive through the media, is clear to me. □ Applies □ Rather applies □ I have not received any such information through the media. □ Does rather not apply □ Does not apply 165 11: Recommendation influenza vaccination [GR_38] For which groups of persons is the influenza vaccination recommended by the Standing Immunization Commission (STIKO) at the Robert Koch Institute? Yes No Don't know [1] For the elderly over 60 years. □ □ □ [2] For all adults over 18 years. □ □ □ [3] For persons with increased health risk due to chronic condition. □ □ □ [4] For children who visit a children's day-care center. □ □ □ [5] For persons who work in the medical field and have contact with the patient. □ □ □ [6] For women who are pregnant during the winter half year.