Fig. 1

Flowchart of the study. a Traumatic brain injury diagnoses before recruitment were identified according to the International Classification of Diseases-10 codes (S06, S02.0, S02.1, S02.7, S02.8, S02.9) using hospital inpatient records. b Caucasian ancestry refers to a genetic ethnic group, involving individuals who self-identified as White British and have very similar genetic ancestry based on a principal components analysis of the genotypes