1. Department of Community Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden, Primary Health Care Research and Development Unit, Centre for Public Health, Linköping, Sweden: Correspondence address: Ingemar Åkerlind Primary Health Care Research and Development Unit Centre for Public Health S-581 85 Linköping Sweden
2. Department of Community Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden,