Dementia Risk After Traumatic Brain Injury vs Nonbrain Trauma

Traumatic Brain Injury As a Risk Factor for Alzheimer’s Disease: Current Knowledge and Future Directions

“…Over a 7-year period, veterans with any history of TBI were more likely (16%) to have a dementia diagnoses recorded in the medical record than those with no history of TBI (10%) after adjusting for the competing risk of death, demographics, and medical and psychiatric co-morbidities (adjusted HR [95% CI]: 1.57 [1.35-1.83]) [37]. In the Gardner et al study [38], however, statewide administrative health data were used to identify a sample of individuals whose records indicated emergency department or inpatient hospital treatment for TBI over a 2-year period, and these cases were compared with a control group of individuals who were treated for non-TBI trauma over this same period. Both groups were followed for 5-7 years, and those with a recent TBI were more likely than their non-TBI [38].…”

“…Two of these studies [37,38] were retrospective cohort studies of adults who were aged 55 years or older and dementia-free at baseline, and diagnosis of TBI and subsequent dementia were obtained through medical record review. The sample studied by Barnes et al [37] consisted of veterans and available records did not include the date of TBI, which means it was not known whether the TBI was recent or remote.…”

“…In the Gardner et al study [38], however, statewide administrative health data were used to identify a sample of individuals whose records indicated emergency department or inpatient hospital treatment for TBI over a 2-year period, and these cases were compared with a control group of individuals who were treated for non-TBI trauma over this same period. Both groups were followed for 5-7 years, and those with a recent TBI were more likely than their non-TBI [38]. After stratifying by age and TBI severity, the authors reported that moderate-severe TBI was associated with increased dementia risk across all age groups, though mTBI was only associated with increased dementia risk above aged 65 years.…”

Age at injury influences dementia risk after TBI

“…6 Several previous clinical studies have used a methodology comparing incidence of dementia in patients with TBI to that of the general population. In the new study by Gardner et al 1 a more relevant index population of over 112,000 patients exposed to trauma without TBI provides the 'control' population. Over a follow-up period of up to 7 years after the original injury dementia risk in a cohort of almost 52,000 patients with TBI was assessed in comparison to this cohort of patients exposed to trauma without TBI.…”

“…8 To avoid the confounding influence of 'normal' ageing, many studies investigating TBI-associated neurodegenerative pathologies often exclude older individuals and focus on younger patients. However, the study by Gardner et al 1 underlines the pressing need to further examine the interplay between TBI, age and dementia risk. The presence of comorbidities, and their potential contribution to pathophysiology is of particular relevance in this older age group.…”