There appears to be an association between head injury and olfactory dysfunction, according to a study published in JAMA OtolaryngologyHead & Neck Surgery. Andrea L.C. Schneider, MD, PhD, and colleagues examined associations between prior head injury, number of injuries, and injury severity with subjective and psychophysical olfactory function. Among 5,951 adults, 28% had a history of head injury, which was associated with an increased likelihood of subjective olfactory dysfunction (24% vs 20% with no head injury) and objective anosmia (15% vs 13% with no head injury). When adjusting for sociodemographics and medical comorbidities, including cognition, participants with a history of head injury were more likely to self-report subjective olfactory dysfunction and were more likely to have objective anosmia. “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,” Dr. Schneider and colleagues wrote.

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