Association of prior head injury with sense of smell in older adults

Study in JAMA Otolaryngology-Head &Neck Surgery investigated the associations of prior head injury, number of prior head injuries, and head injury severity with subjective and psychophysical olfactory function in older adults and to examine concordance between subjective and objective olfactory function among individuals with and without head injury.

The prospective cohort study included 5951 participants who attended Atherosclerosis Risk in Communities (ARIC). Data analysis was performed between November 2021 and May 2022. Self-reported subjective olfactory dysfunction was assessed by the question, "Do you suffer from smell loss or a significantly decreased sense of smell?"

The total of 5951 participants were female,1356 (22.8%) were of Black race, and 1666 (28.0%) had a history of head injury. Participants with prior head injury were more likely than individuals without prior head injury to report subjective olfactory dysfunction (24% vs 20%) and have objective anosmia (15%vs13%) but had lower concordance between subjective and objective assessment (72%vs77%).

In logistic regression models adjusted for socio demographics and medical comorbidities including cognitive status, participants with a history of prior head injury, particularly individuals with 2 or more prior head injuries and more severe head injuries, were more likely to self-report subjective olfactory dysfunction and were more likely to be found to have objective anosmia compared with participants with no history of head injury.

Findings of this cohort study provide evidence supporting the association between head injury and olfactory dysfunction, particularly among individuals who experienced multiple prior head injuries and among individuals with more severe head injury. The findings also suggest that individuals with prior head injury were more likely to bothunder–self-report and over–self-report deficits compared with objective olfactory testing; therefore, it may be important to consider objective olfactory testing in this patient population.

Reference: JAMA Otolaryngol Head Neck Surg. doi:10.1001/jamaoto.2022.1920 Published online July 21, 2022.