(A) Proportional hazard ratio plots of the estimated risk of dementia versus patient age at first TBI event in the presence of comorbid SCI, after adjustment for sex and known risk factors. No SCI comorbidity was used as a reference. (B) Proportional hazard ratio plots of the estimated risk of dementia versus patient age at first TBI event in the presence of comorbid SCI, by sex, after adjustment for known risk factors. No SCI comorbidity was used as a reference. Abbreviations: F, female; M, male; TBI, traumatic brain injury; SCI, spinal cord injury.