Effect of cigarette smoke on gustatory sensitivity, evaluation of the deficit and of the recovery time-course after smoking cessation

Abstract

Background: Study results have shown that chronic exposure to cigarette smoke affects the taste function in humans. However, neither the quantitative impact on taste sensitivity nor the time-course of taste recovery on stopping smoking have been precisely examined.

Methods: The experimental design included 2 phases, (i) a case-control phase comparing the taste sensitivity level measured by Electrogustometric (EGM) thresholds from various parts of the tongue (locus) between smokers (n = 83) and non-smokers (n = 48), (ii) a follow-up study looking at the taste sensitivity recovery in smokers after smoking cessation (n = 24) and compared with non-smokers.

Results: Smokers exhibited significantly lower taste sensitivity than non-smokers - the higher the nicotine dependence (Fagerström scores), the lower the taste sensitivity. After smoking cessation, EGM thresholds decreased progressively, and reached the taste sensitivity range of non-smokers depending on locus and time. After 2 weeks a recovery could be observed on the 3 Tip and the 2 edge loci; the recovery in the posterior loci was complete after 9 weeks, and in the dorsal loci recovery was observed only after 2 months or more.

Conclusions: Smoking cessation does lead to a rapid recovery of taste sensitivity among smokers, with recovery time found to differ based on the sensitivity of loci of the tongue. The use of EGM could potentially be explored as a motivational tool for smoking cessation.

Keywords: Electrogustometry; Taste disturbance; Taste recovery; Tobacco smoking.

Fig. 1

Flow sheet describing groups and drop out

Fig. 2

Location of the 9 recording loci on the surface of the tongue. T, tip; Tr and Tl, tip right and tip left (fungiform papillae); Er and El, edge right and edge left (foliate papillae); Dr and Dl, dorsal right and dorsal left (fungiform papillae); Pr and Pl, fungiform papillae just anterior to the circumvallate papillae

Fig. 3

Effect of smoking on Electrogustometric thresholds. Box plot distribution of electrogustometric (EGM) thresholds (log) recorded in Non-Smokers (N = 48) and Smokers (N = 83) at nine loci on the tongue. (Each box plot presents from bottom to top: “•” = outliers, 5^th percentile value, first quartile (Q1), median, third quartile (Q3), 95^th percentile value), outliers; “+” (linear mixed model test p < 0.001)

Fig. 4

Variations of EGM thresholds during the first 2 months after quitting day. (KW test at 4 weeks: p > 0.41, at 9 weeks: p > 0.87)