Association of Head Injury with Brain Amyloid Deposition: The ARIC-PET Study

Abstract

Our objective was to examine associations of head injury with total and regional brain amyloid deposition. We performed cross-sectional analyses of 329 non-demented participants (81 with prior head injury) in the Atherosclerosis Risk in Communities-Positron Emission Tomography (ARIC-PET) Study who underwent ^18-florbetapir PET imaging in 2012-2014. A history of head injury was defined by self-report or emergency department/hospitalization International Classification of Diseases, Ninth Revision codes. Generalized linear regression models adjusted for demographic, socioeconomic, and dementia/cardiovascular risk factors were used to estimate prevalence ratios (PRs; 95% confidence intervals [CIs]) for elevated (> 1.2) global and regional standard uptake value ratios (SUVRs). Mean age of participants was 76 years, 57% were women, and 43% were black. Head injury was associated with increased prevalence of elevated SUVR >1.2 globally (PR: 1.31; 95% CI: 1.19-1.57), as well as in the orbitofrontal cortex (PR: 1.23); (95% CI: 1.04-1.46), prefrontal cortex (PR: 1.18; 95% CI: 1.00-1.39), superior frontal cortex (PR: 1.24; 95% CI: 1.05-1.48), and posterior cingulate (PR: 1.26; 95% CI: 1.04-1.52). There also was evidence for a dose-response relationship, whereby a history of ≥1 head injury was associated with elevated SUVR >1.2 in the prefrontal cortex and superior frontal cortex compared with persons with a history of one head injury (all, p < 0.05). In conclusion, head injury was associated with increased amyloid deposition globally and in the frontal cortex and posterior cingulate, with suggestion of a dose-response association of head injuries with beta-amyloid deposition. Further work is needed to determine if increased amyloid deposition contributes to dementia in this population.

Keywords: PET amyloid imaging; cohort study; epidemiology; head injury.

FIG. 1.

Adjusted prevalence ratios (95% confidence intervals) for the associations of history of head injury with elevated global and regional standard uptake value ratio >1.2; N = 329. Model adjusted for age (continuous; years), sex (male; female), race (white; black), field center (Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi), education (< high school; high school, General Education Development [GED], or vocational school; college, graduate, or professional school), smoking status (never; former; current; not reported), alcohol consumption (never; former; current; not reported), hypertension (yes; no), diabetes (yes; no), cardiovascular disease (yes; no), stroke (yes; no), depression (yes; no), apolipoprotein E (APOE) ɛ4 alleles (0 alleles; 1 or 2 alleles), and mild cognitive impairment (yes; no). Bolded data represents p < 0.05.