Funding for this research was provided by:
Limburg provincial authorities (Project Number 200130003)
Friesland Campina (Project Number LLMV00)
Received: 11 December 2018
Accepted: 7 May 2019
First Online: 6 June 2019
Consent for publication
: Not applicable.
: GM is part of the editorial board of BMC Public Health. The other authors declare that they have no competing interests.
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