1. Anna-Lena Andersson, Department of Social Medicine, Göteborg University, Göteborg, Sweden, Address for correspondence: Anna-Lena Andersson Department of Social Medicine Göteborg University Vasa Hospital S-41133 Göteborg Sweden
2. Lars-Olof Dahlbäck, Department of Surgery, Uddevalla Hospital, Uddevalla, Sweden
3. Peter Allebeck, Department of Social Medicine, Göteborg University, Göteborg, Sweden