Evaluation of smoking on olfactory thresholds of phenyl ethyl alcohol and n-butanol

The effect of smoking on the sense of smell remains inconclusive. Previous research suggests that this is due to idiosyncratic acuity dependent on the odorants used in testing. Specifically, it appears that smokers have reduced olfactory acuity to odorants found within cigarettes compared with odorants not within cigarettes. Given that some of these odorants are used in tomography and magnetic resonance imaging, an in-depth understanding of this phenomenon in smoking individuals is crucial.This study assesses the variation of olfactory thresholds in smokers based on selective impairment to two odors commonly used in olfactory testing — n-butanol and phenyl ethyl alcohol (PEA). We presented to 46 participants an 18 step, forced choice, three choice ascending staircase method sniff bottle threshold test using n-butanol and PEA. PEA is present in cigarettes while n-butanol is not. Therefore n-butanol is used as a covariate to control for variance explained by any general olfactory dysfunction. Using this method, we can focus solely on selective impairment.We discovered that n-butanol threshold scores were significantly different between smokers and nonsmokers. In addition, after using n-butanol as covariate, phenyl ethyl alcohol scores remained significantly different between groups. This data suggests that there is an extended impairment to odors within tobacco and this may explain a cause of the inconclusiveness of past research.

► Investigated the effect of smoking for n-butanol and phenyl ethyl alcohol thresholds.
► We found that smokers have significantly reduced acuity to detect both odors.
► Phenyl ethyl alcohol was significantly poorer and represented additional deficits.
► The additional deficits affect odors within tobacco.
► This explains prior research disagreements on the effect of smoking on olfaction.