1. University of Birmingham, Centre for Cardiovascular Sciences, City Hospital, Birmingham B18 7QH and Sandwell Medical Research Unit, Sandwell General Hospital, West Bromwich, West Midlands B71 4HJ, UK
2. Primary Care Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
3. Department of Cardiovascular Medicine, University of Manchester, Manchester M13 9NT, UK
4. Division of Medical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
5. Department of Obstetrics and Gynaecology, University Hospital of North Staffordshire, Stoke-on-Trent, UK
6. Department of Psychiatry, Derby City General Hospital, Uttoxeter Road, Derby DE22 3NE, UK