Received: 4 October 2018
Accepted: 12 April 2019
First Online: 2 May 2019
Ethics approval and consent to participate
: This study involved collection and analysis of fully anonymized data, so no ethical approval was necessary according to Dutch regulations [CitationRef removed, CitationRef removed]. People gave consent upon anonymously completing and returning the questionnaire. Questionnaires were received in de-identified form, containing only data on postal code, sex, and age of the participants. Therefore, names and addresses could not be linked to the questionnaire responses, guaranteeing anonymity of the respondents. Participants were informed that the data they provided were to be analyzed for scientific purposes, and that by returning the questionnaires, they gave consent to do so. No written consent was therefore necessary. Parents were asked to complete the questionnaire and give consent on behalf of their children (family members < 16 years old).
: Not applicable
: The authors declare that they have no competing interests.
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