About the effects of electronic cigarettes on the voice: observational study

Introduction

In June 2025, the World Health Organization identified the tobacco epidemic as one of the most serious threats to humanity. Approximately 1.3 billion people smoke tobacco, and its consumption leads to over 7 million deaths annually, of which 1.2 million are attributable to exposure to second-hand tobacco smoke. The highest rates of tobacco product use are observed in Southeast Asia, where 26.5% of the population smokes. The European region ranks second, with a slightly lower rate of 25.3%. Smoking leads to widespread disability and the spread of chronic diseases, causing substantial economic damage [1].

In the Russian Federation (RF), according to Rosstat data for 2023, 16.4% of Russians over 15 years of age smoke daily, and another 2.3% smoke occasionally. In terms of the adult population, this amounts to approximately 22.6 million people. Anti-tobacco measures have led to a gradual decline in the total number of smokers in the country. Whereas in 2019, 24.2% of the country's population smoked, the percentage of smokers decreased to 18.7% in 2023. Despite this overall reduction in smoking, the user base of electronic cigarettes is growing. In 2023, the number of vapers in the RF was estimated at approximately 8–10 million people, i.e., between 9.6% and 12% of the adult population. Typically, 70% of nicotine users consume several different products simultaneously: both conventional cigarettes and vapes. Electronic nicotine delivery systems are preferred by 17.5% of smokers, which is approximately one in six [2].

The use of electronic cigarettes is growing rapidly among young people. The main reasons for the popularity of vaping include sweet flavors and attractive aromas, the absence of strongly odorous smoke clouds, the design, compact size, and form factor of the devices, which make it easier to conceal the gadget and the act of smoking itself. Furthermore, nicotine in electronic cigarettes is presented not in its free form but as a benzoic acid salt, which accelerates its delivery to the bloodstream and reduces unpleasant sensations in the mouth. Due to these "advantages," users perceive vapes as safer for health and less addictive than conventional cigarettes [3].

Vapes are devices among electronic nicotine delivery systems that mimic tobacco smoking without burning tobacco. The commercialization of vaping devices officially began in 2007. Marketing promises positioned electronic cigarettes as a "safer" alternative to conventional tobacco products [4]. The operating principle of electronic cigarettes is very simple and is reflected in the name "vaping," derived from the English word "vaping." A vape consists of a metal coil wrapped with wicking material that absorbs the e-liquid. The metal coil is heated by an electric current from a battery. The liquid base is converted into an aerosol by heat, which the user inhales through a mouthpiece [5]. Although vapes do not involve the harmful combustion process used by traditional cigarettes, their negative effects are diverse due to the heterogeneous composition of ingredients in the vaporized liquids and the specifics of their delivery [6].

The main components of the e-liquid base are propylene glycol and vegetable glycerin, mixed with varying concentrations of nicotine, flavorings, and other additives such as heavy metal salts, acetone, and formaldehyde. Each aerosol component has its own toxic effect. Vitamin E acetate, when heated, has a damaging effect on lung tissue. Propylene glycol and glycerin in their gaseous state disrupt lipid homeostasis and the body's immune defense, reducing the viability of bronchial cells. Flavorings and oxidation products generated during repeated heating and cooling of the heating coil enhance the toxic effect [7]. Thus, in 2019, vaping caused a new disease that rapidly reached epidemic proportions in the United States and was named EVALI (Electronic–cigarette or Vaping product use Associated Lung Injury). The outbreak of this acute lung injury associated with the use of electronic cigarettes or vapes led to 2,807 hospitalizations, 68 of which were fatal. This fact prompted public concern regarding the health risks associated with vaping, especially among the young population [8-10].

Lung damage caused by inhaling vapor is the most serious and most frequently reported side effect of vaping. However, the American Heart Association has identified other consequences of electronic cigarettes. Effects on the cardiovascular system include reduced myocardial contractility, increased blood pressure, increased risk of arrhythmia, endothelial dysfunction, oxidative stress, and increased platelet aggregation and adhesion. Effects on the central nervous system entail behavioral changes, memory impairment, and muscle spasms. In the immune system, electronic cigarette use is associated with the activation of inflammatory processes and reduced immunity, making young patients more susceptible to infectious diseases such as influenza, COVID-19, and pneumonia [11].

The harmful effects of vapes on the upper respiratory tract differ from those of conventional cigarettes, due to the following factors. Compared to traditional tobacco smoke, the particle size distribution in electronic cigarette vapor is broader. Smaller particles (40–200 nm) are more likely to deposit in the trachea and lower respiratory tract, whereas larger particles (1–2 µm) mainly deposit in the oral cavity and oropharynx. The level of particle deposition is influenced not only by particle mass but also by the device's power. Furthermore, it has been proven that e-cigarette users are significantly more likely to exhale vapor through the nose. These behavioral differences increase the risk of toxic effects of electronic cigarettes on the nasal cavity [12].

Experimental studies on volunteers have shown that exposure to e-cigarette humectants increased the secretion of soluble inflammatory mediators in the oral cavity, nasal cavity, and trachea; induced cytotoxicity in oral epithelial cells and vocal fold fibroblasts; and increased genotoxicity in oral epithelial cells. However, results from animal studies examining histological changes in the upper respiratory tract following exposure to humectant aerosols have been mixed. After 90 days of aerosol exposure in rats, increased nasal secretion, hyperplasia of nasal mucosal cells, and epithelial vacuolization were observed. However, in two other mouse studies, histological changes were observed only when nicotine was added to the humectants. The toxicological effects of humectants were confirmed by studies of the lower respiratory tract: aerosol exposure increased the secretion of inflammatory cytokines in human bronchial epithelial cells compared to control air samples. Moreover, humectant aerosol exposure disrupted lipid homeostasis in alveolar macrophages and mouse airway epithelial cells, leading to reduced surfactant production and increased susceptibility to viral infections. Furthermore, the addition of flavorings, which make electronic cigarettes so popular, exerts additional harmful effects on both the upper and lower respiratory tracts. Thus, the toxicological profile of electronic cigarettes includes cytotoxicity, pro-inflammatory effects, genotoxicity, histological changes, procarcinogenic effects, immunosuppression, impaired healing, ciliary dysfunction, microbiome alterations, and neurotoxicity in various parts of the upper respiratory tract [12].

Other studies have demonstrated biological disturbances even as a result of short-term exposure to electronic cigarettes. Liquid nicotine has been shown to promote the migration of dysplastic oral keratinocytes and may itself be a carcinogen. Additionally, oral cavity and oropharyngeal cancer cells exposed to e-cigarette aerosol acquire resistance to cisplatin due to changes in drug transporters. This finding supports the idea that e-cigarette vapor exposure increases resistance to chemotherapy and may reduce the effectiveness of treatment for oral and oropharyngeal cancer, similar to the effect of tobacco smoke exposure [13].

Despite the great popularity of electronic cigarettes in modern society and numerous studies on their harmful effects on the smoker's body, it should be noted that the number of studies on the impact of vapes on the upper respiratory tract is insufficient to draw exhaustive conclusions. The impact of vapes on the oropharynx and larynx remains the least studied.

Objective

The objective of our study was to analyze the pattern of laryngeal pathology in electronic cigarette users.

Material and methods

This was an open, observational clinical study without comparison groups, conducted from 07.05.2025 to 31.12.2025 at the multidisciplinary medical center of the Persona Group of Companies LLC, Nizhny Novgorod, with the participation of the Department of Otorhinolaryngology of the Yaroslavl State Medical University, Ministry of Health of the Russian Federation. The clinical site had an otorhinolaryngology office equipped with the endoscopic equipment necessary for specialized examination of patients with laryngeal diseases and voice disorders. Inclusion criteria for the study were: 1) patient age 18 years and older; 2) regular (daily) and prolonged (at least 1 year) use of electronic cigarettes; 3) any chronic diseases or physical factors that could be considered a potential cause of organic pathology in the larynx: diabetes mellitus, gastroesophageal reflux, allergic diseases, bronchial asthma, systemic vasculitis, menstrual cycle disorders in women, occupational hazards; 4) any previous surgical interventions on the larynx. A mandatory condition was the patient's signed informed consent to participate in the study. Patients were excluded from the study if they presented with: 1) age under 18 years; 2) acute laryngeal pathology due to acute respiratory infection (acute laryngitis); 3) laryngeal trauma, including past history of such trauma; 4) oncological patients undergoing chemotherapy or radiation therapy. Pregnant and breastfeeding women who were electronic cigarette users were not excluded from the study.

During the specified period, 350 electronic cigarette users consulted an otorhinolaryngologist for examination. Of these, 194 individuals (55.4%) complained of voice changes; subsequently, these individuals were included in the study. Patient ages ranged from 19 to 66 years, with a mean age of 41.5±3.7 years. There were 108 men (55.7%) and 86 women (44.3%). Among them, 143 patients were former tobacco smokers who had switched to electronic cigarettes for various reasons. Total smoking duration ranged from 2 to 26 years. The mean duration of tobacco smoking was 11.5±3.3 years (range 10 to 26 years), and the mean duration of electronic cigarette use was 3.4±1.3 years (range 2 to 6 years). Fifty-one electronic cigarette users had never smoked tobacco cigarettes. Their duration of electronic cigarette use was 2.1±1.2 years (range 1 to 4 years).

All patients included in the study underwent a comprehensive examination, which included assessment of medical history, complaints, subjective assessment of voice quality using the widely accepted Yanagihara scale (score 0–4), standard ENT examination, and laryngeal endoscopy. Optical laryngoendoscopy was performed using an "Azimut" telolaryngoscope with an 80 mm diameter and 70° lateral-viewing optics.

Since the laryngeal pathology identified in electronic cigarette users was diverse, various algorithms and techniques for treatment and vocal function rehabilitation were employed. Based on the established diagnosis, treatment regimens included anti-inflammatory drugs, inhalation and physiotherapeutic procedures, and phonopedic correction. The criteria for effectiveness of conservative therapy were restoration of the laryngoscopic picture to normal, or a significant reduction in the severity of the inflammatory process in the larynx, and restoration or improvement of voice intensity and sonority. A mandatory condition of therapy was the patient's cessation of electronic cigarette use. Overall, the treatment effect was assessed as "satisfactory" or "no effect." In some cases, patients were referred for surgical treatment, indicated for space-occupying lesions of the larynx (benign and malignant tumors).

Statistical processing of the study results was performed using IBM SPSS Statistics V27 software, including Student's t-test (for quantitative variables with normal distribution), Pearson's chi-square test (for comparing qualitative variables), and the Wilcoxon W-test to assess differences between two related groups with non-normal distributions. A p-value <0.05 was considered the threshold for statistical significance. All analyzed characteristics were classified as quantitative; their assessment employed Shapiro-Wilk normality testing, descriptive statistics, Levene's test for homogeneity of variances, and Pearson's correlation analysis. Correlation was considered high if the correlation coefficient r was equal to or exceeded 0.75 (r ≥ 0.75).

Results and discussion

The main complaints of the patients were hoarseness, roughness of the voice or huskiness, as well as further deterioration of voice timbre after any vocal strain. Most patients reported changes in voice quality throughout the day. Dysphonia was typically more pronounced in the morning hours upon waking. At the same time, there was an urge to "clear the throat," and a cough, usually dry and paroxysmal, appeared, after which the voice became clearer but did not recover to the level of sonority present before the illness. By evening, the severity of dysphonia increased again. Twenty-seven patients noted the appearance of breathiness during speech and physical exertion.

The endoscopic picture of the larynx was diverse, corresponding to the established diagnoses. Chronic catarrhal laryngitis was diagnosed in 109 (56.2%) patients (67 men, 42 women). Chronic hyperplastic laryngitis was present in 46 patients (23.7%): 32 men, 14 women. Chronic edematous-polypous laryngitis (Reinke's edema) was identified in 31 patients (15.9%), including 7 men and 24 women; vocal fold polyps in 7 patients (3.6%) (two men and five women); and a malignant laryngeal tumor (cancer) in 1 woman (0.6%).

Several clinical observations are presented as illustrations.

Clinical observation 1

A 21-year-old male, vocalist, student at a music conservatory, tenor. Complained of persistent, prolonged (over 3 months) hoarseness, lowering of voice pitch, and narrowing of vocal range. He was periodically bothered by a cough, a feeling of discomfort and tickling in the throat. Duration of electronic cigarette use: 2 years. He could not specify the exact number of puffs per day. Somatic health was normal. Endolaryngoscopy revealed hyperemia and edema of the vocal folds along their entire length. During phonation, the vocal folds did not close completely, forming a linear gap. A moderate amount of clear mucus was present in the larynx. The laryngeal ventricles were not visible. The arytenoids and interarytenoid area were unremarkable (Fig. 1). The voice was husky; its Yanagihara scale score was 3 (severe dysphonia). Diagnosis: Chronic catarrhal laryngitis.

Fig. 1. Endophoto of the larynx of a 21-year-old man. Chronic catarrhal laryngitis

Clinical observation 2

A 47-year-old woman consulted with complaints of persistent dysphonia for approximately 6 months and morning coughing. Non-voice profession. Duration of tobacco smoking: 10 years; electronic cigarette use: 3 years. Number of puffs per day: between 10 and 20, she could not specify exactly. She considered herself somatically healthy. Endolaryngoscopy visualized pronounced, cushion-like edema of the vocal folds, more pronounced along the free edge. During phonation, the vocal folds exhibited a "sailing" movement. The laryngeal ventricles were visible. The arytenoids and interarytenoid area were unremarkable (Fig. 2). The voice was hoarse; Yanagihara scale score: 3 (severe dysphonia). Diagnosis: Chronic edematous-polypous laryngitis (Reinke's edema) stage 2-3. The patient underwent surgery with a satisfactory functional outcome. She completely quit smoking.

Fig. 2. Endophoto of the larynx of a 47-year-old woman. Chronic edematous polypous laryngitis

Clinical observation 3

A 41-year-old woman consulted with complaints of marked hoarseness for a long time (she could not remember exactly how long) and progressive shortness of breath. Non-voice profession. Duration of electronic cigarette use: 5 years. Number of puffs per day: at least 15, sometimes more. She considered herself somatically healthy. She had been examined by a pulmonologist, and no pathology of the lower respiratory tract was found. Endolaryngoscopy visualized pronounced, cushion-like edema of the vocal folds, more pronounced on the right. During phonation, the vocal folds exhibited a "sailing" movement. The left laryngeal ventricle was visible. The arytenoids and interarytenoid area were unremarkable (Fig. 3). The voice was hoarse; Yanagihara scale score: 3 (severe dysphonia). Diagnosis: Chronic edematous-polypous laryngitis (Reinke's edema) stage 3. The patient was referred for surgical treatment. She did not quit smoking but reduced the frequency of electronic cigarette use.

Fig. 3. Endophoto of the larynx of a 41-year-old woman. Chronic edematous-polypous laryngitis

Clinical observation 4

A 36-year-old woman consulted with complaints of marked hoarseness for more than 1 month, tickling, and a sensation of a lump in the throat. Non-voice profession. Duration of electronic cigarette use: approximately 5 years; she also smokes hookah occasionally. She considered herself somatically healthy. Endolaryngoscopy revealed that the right vocal fold was hyperemic, edematous, with a tuberous whitish formation with indistinct borders in the anterior and middle third of the fold (Fig. 4). During phonation, closure of the vocal folds was incomplete due to restricted mobility of the right vocal fold. The voice was hoarse, weak; Yanagihara scale score: 3. Given the nature of the laryngoscopic picture, a neoplasm of the right vocal fold was suspected. The patient was referred for biopsy examination to the Nizhny Novgorod Oncology Hospital, where supportive direct laryngoscopy with laryngeal biopsy was performed under intubation anesthesia. The histological examination result of the laryngeal material was well-differentiated squamous cell carcinoma with keratinization.

During the comprehensive examination of the patient, no evidence of regional or distant tumor metastasis was found. The patient received combined treatment consisting of right-sided total chordotomy and radiation therapy. Voice sonority was almost completely restored 4 months after completing therapy. The woman is currently under the supervision of an oncologist. She has completely quit smoking.

Fig. 4. Endophoto of the larynx of a 36-year-old woman. Squamous cell carcinoma of the larynx, right vocal fold. T1N0M0

Results

Following therapy, 135 out of 194 patients presented for follow-up examinations, which constituted less than 70% (specifically, 69.6%). Consequently, it was not possible to track symptom dynamics, assess treatment efficacy, or analyze the percentage of smoking cessation for every study participant. Almost one-third of patients (30.4%) were non-compliant with regard to follow-up monitoring. This high rate of low compliance is most likely due to several reasons, which may include the patient's remote residence (rural areas) and an unwillingness to abandon harmful habits, primarily smoking.

Overall, a "satisfactory" treatment effect was recognized in 98 out of 135 patients (72.6%). No treatment effect was observed in 37 patients (27.4%). Only 40 electronic cigarette users (29.6%) completely quit smoking. A total of 81 individuals (60%) reduced their electronic cigarette consumption, decreasing the number of daily smoking episodes. A total of 14 individuals (10.4%) did not change their smoking habit in any way.

Additional clinical observations are provided below.

Clinical observation 5

A 63-year-old woman consulted an otorhinolaryngologist with complaints of tickling and a sensation of a foreign body in the throat, obsessive cough, and hoarseness. Periodically, her voice would "disappear" to a whisper. Non-voice profession. Duration of smoking: 26 years; she switched to electronic cigarettes 6 years ago. Optical laryngoscopy revealed papillary growths in the interarytenoid region (visually, pachydermia). The vocal folds were hyperemic, edematous, with localized, tuberous, whitish thickened areas in the middle third, more pronounced on the right (Fig. 5a). During phonation, closure of the vocal folds was incomplete, forming a linear-triangular gap. The voice was hoarse, rough, low; Yanagihara scale score: dysphonia grade 4. Diagnosis: Chronic hyperplastic laryngitis.

Fig. 5a. Endophoto of the larynx of a 63-year-old woman before therapy. Chronic hyperplastic laryngitis

With conservative anti-inflammatory inhalation therapy combined with systemic use of proteolytic enzyme group drugs, the patient reported a reduction in the sensation of tickling in the throat and slight improvement in vocal function. Voice quality on the Yanagihara scale was assessed as 3 points. Laryngoscopy showed insignificant improvement (Fig. 5b). She did not quit smoking.

Fig. 5b. Endophoto of the larynx of a 63-year-old woman 1.5 months after the start of therapy

Clinical observation 6

A 38-year-old male, vocalist, non-professional singer, consulted with complaints of hoarseness, tickling and a sensation of a foreign body in the throat, and soreness in the pharynx when singing. Duration of smoking: 17 years. Former tobacco smoker, currently uses electronic cigarettes, sometimes hookah. Rigid laryngoscopy revealed papillary hyperplasia of the mucosa in the interarytenoid region (visually, pachydermia). The vocal folds were hyperemic, markedly thickened, and tuberous. The right laryngeal ventricle was not visualized, with an "overhang" effect of the right vestibular fold over the vocal fold (Fig. 6a). During phonation, closure of the vocal folds was incomplete, forming a linear gap with an opening in the posterior third of the laryngeal lumen. The voice was hoarse, low; Yanagihara scale score: dysphonia grade 4. Diagnosis: Chronic hyperplastic laryngitis.

Fig. 6a. Endophotograph of the larynx of a 38-year-old man. Chronic hyperplastic laryngitis

The patient was prescribed anti-inflammatory inhalation therapy combined with systemic use of proteolytic enzyme group drugs. During treatment, improvement in voice and reduction in the severity of pharyngeal discomfort were noted. Voice quality on the Yanagihara scale was assessed as 2 points. Laryngoscopy showed significant improvement. The vocal folds showed patchy gray areas, were nearly smooth along the free edge, and were not thickened (Fig. 6b). He did not completely quit using electronic cigarettes but reduced the number of daily smoking episodes.

Fig. 6b. Endophoto of the larynx of a 38-year-old man one and a half months after the start of anti-inflammatory therapy. Chronic hyperplastic laryngitis, improvement

Clinical observation 7

A 34-year-old female, vocalist, consulted with complaints of marked hoarseness, lowering of voice timbre, and narrowing of vocal singing range. Duration of smoking: 15 years, of which she has been using electronic cigarettes for 6 years. Rigid laryngoscopy revealed a polypoid formation at the border of the anterior and middle third of the left vocal fold along its free edge (Fig. 7a). During phonation, closure of the vocal folds was incomplete, forming a triangular gap in the posterior third of the laryngeal lumen. The voice was hoarse, low; Yanagihara scale score: 3. Diagnosis: Chronic edematous-polypous laryngitis (Reinke's edema), stage 1. The patient was referred for surgical treatment. She completely quit using electronic cigarettes.

Fig. 7a. Endophotograph of the larynx of a 34-year-old woman. Diagnosis: chronic edematous polypous laryngitis (Reinke's edema)

The patient underwent endolaryngeal resection of the polypoid-altered mucosa of the left vocal fold. The postoperative period was uneventful. Within a month, voice sonority was completely restored, and vocal range expansion was noted. On follow-up endolaryngoscopy performed 1.5 months after surgery, the vocal folds showed no pathological changes; their free edges were smooth and non-edematous. Gaping of the left laryngeal ventricle was observed (Fig. 7b).

Fig. 7b. Endophoto of the larynx of a 34-year-old woman with a diagnosis of chronic edematous polypous laryngitis (Reinke's edema) 1.5 months after surgical treatment

The patient completely quit smoking and returned to professional vocal activity.

Thus, the presented study encompassed 194 smoking patients with chronic inflammatory diseases and space-occupying lesions of the larynx. Women constituted 55.4%, and the mean age of participants was approximately 41.5 years, with a predominance of individuals over 40 years of age (55.7%). In the majority of cases, combined laryngeal pathology was present, which aggravated the severity of the disease and required a combined approach to therapy with mandatory smoking cessation as the first step in patient management.

Conclusions

1. The study revealed significant correlations between the intensity of smoking (number of puffs per day) and the severity of the hyperplastic process in the larynx (r > 0.75, p < 0.05). However, it was not possible to determine with complete certainty the average daily number of electronic cigarette use episodes by patients. No clear correlation was found between smoking duration and the severity of chronic laryngeal disease.

2. In hyperplastic laryngitis, most cases require combined therapy and enhanced monitoring to prevent disease progression.

3. Among smokers with chronic laryngeal diseases, the percentage of non-compliance with follow-up monitoring is high, primarily due to an unwillingness to quit smoking and a lack of understanding of the negative impact of vapes on the respiratory tract.

4. Further prospective studies are needed to clarify the long-term outcomes of follow-up for patients who abuse electronic cigarettes.

In conclusion, attention should be drawn to a recommendation that would be useful not only for patients but also for their relatives and for physicians involved in the rehabilitation of patients with upper respiratory tract pathology. Patients who consider vaping as an alternative to conventional cigarettes or an intermediate step towards smoking cessation should be aware that there is no "safe" smoking, and the use of electronic cigarettes carries its own negative consequences, many of which remain to be studied.