[This corrects the article DOI: 10.2196/publichealth.7009.].
©Naoe Tatara, Hugo Lewi Hammer, Hege Kristin Andreassen, Jelena Mirkovic, Marte Karoline Råberg Kjøllesdal. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 31.08.2018.