[1] Sophiahemmet Univ, Dept Hlth Promot Sci, Stockholm, Sweden
[2] Uppsala Univ, Dept Psychol, Uppsala, Sweden
[3] Karolinska Inst, Inst Environm Med, Unit Intervent & Implementat Res Worker Hlth, Stockholm, Sweden
[4] Karolinska Inst, Dept Clin Neurosci, Stockholm, Sweden
[5] Naprapathogskolan Scandinavian Coll Naprapath Manu, Stockholm, Sweden