©Naoe 
Tatara, 
Hugo 
Lewi 
Hammer
, Hege 
Kristin 
Andreassen, 
Jelena 
Mirkovic, 
Marte 
Karoline 
Råber
g Kjøllesdal. 
Originally
published 
in JMIR 
Public 
Health 
and Surveillance 
(http://publichealth.jmir
.org), 05.10.2017. 
This is an open-access 
article
distributed 
under 
the terms 
of the Creative 
Commons 
Attribution 
License 
(https://creativecommons.or
g/licenses/by/4.0/), 
which
permits 
unrestricted 
use, distribution, 
and reproduction 
in any medium, 
provided 
the original 
work, 
first published 
in JMIR 
Public
Health 
and  Surveillance, 
is  properly 
cited.
Med mindre annet er angitt, så er denne innførselen lisensiert som ©Naoe Tatara, Hugo Lewi Hammer , Hege Kristin Andreassen, Jelena Mirkovic, Marte Karoline Råber g Kjøllesdal. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir .org), 05.10.2017. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.or g/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Public Health and Surveillance, is properly cited.