Multiple prior head injuries or severe head injury tied to Loss of smell among elderly: JAMA

Traumatic brain injury has been associated with short-term olfactory dysfunction, but the association of a number of prior head injuries and head injury severity with both subjective and objective long-term olfactory function is less clear.

A study was conducted to investigate the associations of prior head injury, a number of prior head injuries, and head injury severity with subjective and psychophysical (objective) olfactory function in older adults and to examine concordance between subjective and objective olfactory function among individuals with and without head injury.

This prospective cohort study included 5951 participants who attended Atherosclerosis Risk in Communities (ARIC) Study visit 5 (2011 through 2013). Data analysis was performed between November 2021 and May 2022.

Results:

• Overall, the 5951 participants were a mean (SD) age of 75.6 (5.2) years, 3501 (58.8%) 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 and have objective anosmia but had lower concordance between subjective and objective assessment
• In logistic regression models adjusted for sociodemographics 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 a more severe head injuries. The findings also suggest that individuals with prior head injury were more likely to both under–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:

Schneider ALC, Gottesman RF, Mosley TH, et al. Associations of Prior Head Injury With Olfaction in Older Adults: Results From the Atherosclerosis Risk in Communities (ARIC) Study. JAMA Otolaryngol Head Neck Surg. Published online July 21, 2022. doi:10.1001/jamaoto.2022.1920

Keywords:

Andrea L. C. Schneider, Rebecca F. Gottesman, Thomas H. Mosley, Association, Prior, Head, Injury, Olfaction, Older, Adults, JAMA Otolaryngology Head Neck Surgery, anosmia, sense of smell