*2.1. Procedure*

The study was based on cross-sectional data from a study called 'Oppvekst i bygder' (Living in rural communities) where data have been collected every five years since 1996. This study used data from three time points (2011, 2016, and 2022), and included adolescents from lower and upper secondary public schools. The data from 2011 and 2016 included five municipalities, and the data from 2022 included four municipalities in Mid-Norway. Teachers administrated the questionnaires during a 45 min classroom session where the students could either choose to answer the questionnaire or do schoolwork. An information letter was sent to all students and parents of those under 16 years of age. Students ≥16 years old gave consent to participate by answering the questionnaire, whereas written parental consent and consent from students were obtained for students 13 to 15 years old. The study procedures were approved by the Regional Committee for Medical Research Ethics Mid-Norway.
