Olfactory dysfunction persists after smoking cessation and signals increased cardiovascular risk

• Published in: International forum of allergy & rhinology Vol. 9; no. 9; pp. 977 - 985
• Main Authors: Siegel, Jesse K., Wroblewski, Kristen E., McClintock, Martha K., Pinto, Jayant M.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-09-2019
• Subjects: Aged; Aged, 80 and over; Aging; Atherosclerosis; Cardiovascular disease; Cardiovascular diseases; Cardiovascular Diseases - epidemiology; Cigarette smoking; Cigarette Smoking - adverse effects; Cigarettes; Cognition; Coronary artery disease; Drug addiction; Female; Follow-Up Studies; Heart attacks; heart disease; Heart diseases; Humans; Incidence; Male; Middle Aged; Morbidity; Myocardial infarction; Odor; Older people; Olfaction; Olfaction disorders; Olfaction Disorders - diagnosis; Olfaction Disorders - epidemiology; Olfaction Disorders - therapy; Olfactory discrimination; Olfactory system; Prognosis; Risk; Smell; Smoking cessation; Smoking Cessation - methods; tobacco; Treatment Outcome; Vascular diseases; atherosclerosis; smoking cessation; heart disease; myocardial infarction; tobacco; aging; smell
• ISSN: 2042-6976; 2042-6984
• DOI: 10.1002/alr.22357

Background
Olfaction plays a critical role in health and function in older adults, and impaired sense of smell is a strong predictor of morbidity and mortality. Smoking cigarettes causes olfactory impairment, but the mechanism of damage and ability to recover after cessation are unknown. We investigated the relationship between time since quitting and olfactory dysfunction in order to elucidate the mechanism(s) by which smoking damages the olfactory system and to inform patient counseling.
Methods
Using longitudinal data from the National Social Life Health and Aging Project (n = 3528 older adults, including 1526 former smokers), we analyzed the association between odor identification performance and time since smoking cessation using multivariate ordinal logistic regression, adjusting for cognition and demographic variables. To test whether vascular disease plays a role, we also assessed the relationship between olfactory decline and incidence of heart attack and heart disease.
Results
Former smokers who quit ≤15 years before testing had significantly impaired olfaction compared to never smokers (p = 0.04), but those who quit >15 years prior did not. Olfactory decline over 5 years showed modest evidence toward predicting increased incidence of heart attack or heart disease (p = 0.08).
Conclusion
Olfactory impairment in smokers persists 15 years after quitting, which is consistent with a vascular mechanism of impairment. Indeed, olfactory decline is a predictor of the development of cardiovascular disease. Taken together, these data suggest that olfactory loss may be a useful sign of underlying vascular pathology. Further investigation of olfactory loss as an early biomarker for cardiovascular disease is warranted.