Funding for this research was provided by:
Rijksinstituut voor Volksgezondheid en Milieu (S/133002)
Received: 11 April 2018
Accepted: 25 September 2018
First Online: 20 October 2018
Ethics approval and consent to participate
: The Medical Research Involving Human Subjects Act (WMO) does not apply to this study, and official approval was not required [CitationRef removed]. Participants agreed to the terms of service of Zorgkaart Nederland, which states that their submission can be used anonymously for research purposes [CitationRef removed].
: Not applicable.
: The authors declare that they have no competing interest.
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