Moderate-to-severe traumatic brain injury ups risk of dementia
The risk of future dementia is higher for working-aged individuals with histories of moderate-to-severe traumatic brain injuries (TBI), a new retrospective cohort study has found. The risk of Parkinson’s disease (PD) or amyotrophic lateral sclerosis (ALS) is unaffected.
The study included 19,936 working-aged, moderate-to-severe TBI patients (mean age 46 years; 23 percent female). Working-aged individuals hospitalized for mild TBIs (n=20,703; mean age 39 years; 39 percent female) were included as controls. The study outcome was the development of neurodegenerative disorders (NDD) including dementia, PD or ALS.
Over the course of the study, 3.5 percent (n=696) of participants with moderate-to-severe TBI developed NDD. In comparison, only 1.6 percent (n=326) of the mild TBI patients had NDD, with the between-group difference reaching significance (p<0.001).
Dementia was the most common NDD type and was observed in 3.1 and 1.3 percent of the moderate-to-severe and mild TBI groups, respectively. This was followed by PD (0.3 and 0.2 percent, respectively) and ALS (0.1 and 0.1 percent, respectively).
The unadjusted NDD rate for the moderate-to-severe and mild TBI groups were 331 and 134 per 100,000 person-years, respectively. Unadjusted rates for dementia (293 vs 114 per 100,000 person-ears), PD (32 vs 17 per 100,000 person-years) and ALS (6 vs 4 per 100,000 person-years) were all higher in the moderate-to-severe TBI group.
The risk of NDD was significantly higher in the moderate-to-severe TBI group compared with the mild TBI group after adjusting for age, sex, level of education and socioeconomic group (hazard ratio [HR], 1.8; 95 percent CI, 1.6 to 2.1; p<0.001).Adjusted models also showed a higher risk of dementia (HR, 1.9; 1.6 to 2.2; p<0.001) but not PD (HR, 1.3; 0.9 to 1.9; p=0.22) and ALS (HR, 1.3; 0.5 to 3.2; p=0.53) in moderate-to-severe TBI patients.