Authors: Gerardine Doyle; Shane O'Donnell; Etáin Quigley; Kate Cullen; Sarah Gibney; Diane Levin-Zamir; Kristin Ganahl; Gabriele Müller; Ingrid Muller; Helle Terkildsen Maindal; Wushou Peter Chang; Stephan Van Den Broucke Journal: BMJ Open Date: 2017-06-04 Impact factor: 2.692