Objective and Subjective Evaluation of Voice Parameters in Early and Late Periods After Smoking Cessation

Objective: Cigarette smoking impairs voice quality by inducing inflammatory and structural changes in the vocal folds, resulting in measurable alterations in acoustic parameters such as jitter, shimmer, and harmonics-to-noise ratio (HNR). However, the temporal pattern of voice recovery after smoking cessation remains insufficiently defined. This study aimed to determine whether smoking cessation leads to early and progressive improvement in objective acoustic voice parameters and subjective voice-related quality of life. The authors hypothesized that cessation would reduce jitter, shimmer, and Voice Handicap Index-30 scores and increase HNR within 3 months. Methods: This prospective controlled study included 38 smokers and 40 non-smokers. Acoustic parameters were analyzed from sustained vowel phonations using Praat software, and subjective voice quality was assessed with the Voice Handicap Index-30 (VHI-30). Smokers were evaluated at baseline, 1 month, and 3 months after smoking cessation; controls were assessed once. Results: After smoking cessation, smokers showed significant progressive improvement in all voice parameters. Voice Handicap Index-30 scores, jitter, and shimmer decreased, whereas HNR increased at both follow-up points (P < .001). At baseline, smokers had worse acoustic parameters than controls. By 3 months, several parameters improved to levels comparable to or better than controls. Voice Handicap Index-30 scores correlated positively with jitter and shimmer and negatively with HNR. Conclusion: Smoking cessation leads to rapid, progressive improvement in objective and subjective voice parameters. These findings suggest that smoking-related vocal impairment is at least partially reversible in the short term and support acoustic analysis for monitoring recovery.