Neuroimaging Biomarkers in UK Biobank

UK Biobank is a major data health resource including ~500,000 participants from across the UK, aged between 40 and 69 years at recruitment^{47 (link)}. The UK Biobank includes clinical and phenotypic information for a broad range of traits and includes MRI imaging data on a subset of participants. In this study, we used the UK Biobank imaging data on ~20,000 individuals released in October 2018^{11 (link),12 (link)}. MRI was performed on two identical Siemens Skyra 3.0 T scanners (Siemens Medical Solutions, Germany), running VD13A SP4, with a standard Siemens 32-channel RF receiver head coil. Identical acquisition parameters and careful quality control (QC) was used for all scans. We selected individuals described for three phenotypes all of which variables already obtained from the UK Biobank MRI data by the central MRI analysis centre in Oxford (1) total volume of WMH (from T1 and T2_FLAIR images) WMH (field 25781), (2) FA (fields 25056-25103) and (3) MD (fields 25104-25151) (see Supplementary Data 9 for field description). Individuals diagnosed with stroke, or with other major CNS disease which could be associated with white matter damage (e.g., multiple sclerosis, Parkinson disease, dementia or any other CNS neurodegenerative condition) were excluded from the analysis (see Supplementary Table 5 for removed codes description).