1. Research & Development Unit of Primary Health Care, Halland, Sweden, , Department of Primary Health Care, Gothenburg University, Gothenburg, Sweden
2. Research & Development Unit, Central Hospital, Halmstad, Sweden
3. Institute of Community Medicine, University Hospital, Malmö, Sweden
4. Statistical Consultation, Valler, Sweden
5. Research & Development Unit, Central Hospital, Halmstad, Sweden, Institute of Community Medicine, University Hospital, Malmö, Sweden