Olfactory dysfunction persists after smoking cessation and signals increased cardiovascular risk

Area of Science:

• Gerontology
• Neuroscience
• Public Health

Background:

• Impaired sense of smell (olfaction) is a significant predictor of morbidity and mortality in older adults.
• Cigarette smoking is known to cause olfactory impairment, but the underlying mechanisms and recovery potential post-cessation remain unclear.
• Understanding the long-term effects of smoking on olfaction is crucial for patient counseling and public health strategies.

Purpose of the Study:

• To investigate the association between time since smoking cessation and olfactory dysfunction in older adults.
• To elucidate the mechanisms by which smoking impacts the olfactory system.
• To explore olfactory decline as a potential early biomarker for cardiovascular disease.

Main Methods:

• Analysis of longitudinal data from 3528 older adults (1526 former smokers) in the National Social Life Health and Aging Project.
• Multivariate ordinal logistic regression was used to assess the relationship between odor identification performance and time since smoking cessation, adjusting for cognitive and demographic factors.
• The association between olfactory decline and the incidence of heart attack and heart disease was evaluated to explore a potential vascular mechanism.

Main Results:

• Former smokers who quit smoking within 15 years demonstrated significantly impaired olfaction compared to never smokers (p=0.04).
• Individuals who quit smoking more than 15 years prior did not show significant olfactory impairment compared to never smokers.
• Olfactory decline over a 5-year period provided modest evidence for predicting an increased incidence of heart attack or heart disease (p=0.08).

Conclusions:

• Olfactory impairment in former smokers persists for at least 15 years, suggesting a potential vascular mechanism of damage.
• Olfactory decline appears to be a predictor of cardiovascular disease development, highlighting its role in vascular pathology.
• Olfactory loss may serve as a valuable early biomarker for underlying vascular pathology, warranting further investigation.