1. School of Health and Population Sciences; University of Birmingham; Edgbaston Birmingham UK
2. Institute of General Practice (ifam); Medical Faculty of the Heinrich Heine University Düsseldorf; Düsseldorf Germany
3. Ninewells Hospital and Medical School; Dundee DD1 9SY and School of Nursing & Health Sciences; University of Dundee; Dundee Scotland
4. Department of Ageing and Health; Ninewells Hospital and Medical School; Dundee UK
5. School of Nursing & Health Sciences; University of Dundee; Dundee UK