title: Olfactory Function and Associated Clinical Correlates in Former National Football League Players.
abstract: Professional American football players incur thousands of repetitive head impacts (RHIs) throughout their lifetime. The long-term consequences of RHI are not well characterized, but may include olfactory dysfunction. RHI has been associated with changes to brain regions involved in olfaction, and olfactory impairment is common after traumatic brain injury. Olfactory dysfunction is a frequent early sequelae of neurodegenerative diseases (e.g., Alzheimer's disease), and RHI is associated with the neurodegenerative disease, chronic traumatic encephalopathy (CTE). We examined olfaction, and its association with clinical measures, in former National Football League (NFL) players. Ninety-five former NFL players (ages 40-69) and 28 same-age controls completed a neuropsychological and neuropsychiatric evaluation as part of a National Institutes of Health-funded study. The Brief Smell Identification Test (B-SIT) assessed olfaction. Principal component analysis generated a four-factor structure of the clinical measures: behavioral/mood, psychomotor speed/executive function, and verbal and visual memory. Former NFL players had worse B-SIT scores relative to controls (p = 0.0096). A B-SIT cutoff of 11 had the greatest accuracy (c-statistic = 0.61) and specificity (79%) for discriminating former NFL players from controls. In the former NFL players, lower B-SIT scores correlated with greater behavioral/mood impairment (p = 0.0254) and worse psychomotor speed/executive functioning (p = 0.0464) after controlling for age and education. Former NFL players exhibited lower olfactory test scores relative to controls, and poorer olfactory test performance was associated with worse neuropsychological and neuropsychiatric functioning. Future work that uses more-comprehensive tests of olfaction and structural and functioning neuroimaging may improve understanding on the association between RHI and olfaction.
authors.affiliation: 1 Department of Neurology, Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Alosco
authors.affiliation: 2 Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.
authors.forename: Johnny
authors.initials: J
authors.lastname: Jarnagin
authors.affiliation: 3 Department of Biostatistics, Boston University School of Public Health , Boston, Massachusetts.
authors.forename: Yorghos
authors.initials: Y
authors.lastname: Tripodis
authors.affiliation: 4 Department of Otolaryngology-Head and Neck Surgery, Boston University School of Medicine , Boston, Massachusetts.
authors.forename: Michael
authors.initials: M
authors.lastname: Platt
authors.affiliation: 2 Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.|5 Data Coordinating Center, Boston University School of Public Health , Boston, Massachusetts.
authors.forename: Brett
authors.initials: B
authors.lastname: Martin
authors.affiliation: 2 Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.|6 Department of Biostatistics, Data Coordinating Center, Boston University School of Public Health , Boston, Massachusetts.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Chaisson
authors.affiliation: 1 Department of Neurology, Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.|7 Interfaculty Initiative in Health Policy , Cambridge, Massachusetts.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Baugh
authors.affiliation: 2 Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.
authors.forename: Nathan G
authors.initials: NG
authors.lastname: Fritts
authors.affiliation: 8 Department of Neurology and Neurosurgery, Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Cantu
authors.affiliation: 1 Department of Neurology, Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.|8 Department of Neurology and Neurosurgery, Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine , Boston, Massachusetts.|9 Department of Anatomy & Neurobiology, Boston University School of Medicine , Boston, Massachusetts.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Stern
mesh_terms: D000328:Adult; D000368:Aged; D056352:Athletes; D001265:Athletic Injuries / Q000150:complications / Q000503:physiopathology*; D001924:Brain Concussion / Q000150:complications / Q000503:physiopathology*; D000070627:Chronic Traumatic Encephalopathy / Q000150:complications / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000209:etiology / Q000503:physiopathology*; D005538:Football; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000209:etiology / Q000503:physiopathology*; D008875:Middle Aged; D000857:Olfaction Disorders / Q000209:etiology / Q000503:physiopathology*; D014481:United States
keywords: American football; National Football League; chronic traumatic encephalopathy; olfaction; repetitive head impacts