1. Institute of Neuroscience, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle University , Newcastle upon Tyne, NE4 5PL , UK
2. Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University , Cardiff, CF24 4HQ , UK
3. Dementia Research Institute & MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University , Cardiff, CF24 4HQ , UK
4. MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University , Cardiff, CF24 4HQ , UK
5. Bristol Population Health Science Institute, Bristol University , Oakfield House, Bristol, BS8 2BN , UK
6. MRC Integrative Epidemiology Unit, University of Bristol , Oakfield House, Bristol, BS8 2BN , UK
7. School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands
8. Mary MacKillop Institute for Health Research, Australian Catholic University , 5/215 Spring St, Melbourne, VIC 3000, Australia