ABSTRACT
Objective: The objective of this systematic review is to determine whether smoking causes organic dysphonia in adults with chronic obstructive pulmonary disease (COPD).
Materials and methods: The review adheres to the PRISMA statement guidelines and involves database selection based on defined key terms. Studies were included or excluded based on specific criteria. The research question was constructed using the PIO model, and the quality of evidence and strength of recommendation were assessed using the GRADE pro GDT system.
Results: The review conducted searches in databases such as PUBMED, SPRINGER LINK, SCIENCEDI-RECT, SCOPUS, and EBSCO, using variable crosses generated from DESC and MESH keywords. After applying filters, a final sample of 30 articles was used in this research. Smoking-induced changes in laryngeal anatomical structure can lead to functional problems and have a negative impact on voice production, resulting in voice disorders. In individuals with COPD, voice quality is further compromised by disease-related symptoms, leading to reduced and irregular voice quality.
Conclusions: Dysphonia is a prevalent finding in adults with COPD, and smoking emerges as one of the primary factors contributing to its occurrence. The review underscores the role of smoking as a causative factor in organic dysphonia among individuals with COPD.
Keywords: Dysphonia, vocal alterations, smoking, voice, COPD.
RESUMEN
Objetivo: El objetivo de esta revisión sistemática fue determinar si el tabaquismo causa disfonía orgánica en adultos con enfermedad pulmonar obstructiva crónica (EPOC).
Materiales y métodos: La revisión se adhiere a las directrices de la declaración PRISMA e implica la selección de bases de datos basada en términos clave definidos. Los estudios se incluyeron o excluyeron en función de criterios específicos. La pregunta de investigación se construyó utilizando el modelo PIO, y la calidad de la evidencia y la fuerza de la recomendación se evaluaron utilizando el sistema GRADE pro GDT.
Resultados: La revisión realizó búsquedas en bases de datos como PUBMED, SPRINGER LINK, SCIEN-CEDIRECT, SCOPUS y EBSCO, utilizando cruces variables generados a partir de palabras clave DESC y MESH. Tras aplicar filtros, se utilizó una muestra final de 30 artículos en esta investigación. Los cambios inducidos por el tabaquismo en la estructura anatómica laríngea pueden dar lugar a problemas funcionales y repercutir negativamente en la producción de la voz, causando trastornos vocales. En los individuos con EPOC, la calidad de la voz se ve aún más comprometida por los síntomas relacionados con la enfermedad, lo que conduce a una calidad de voz reducida e irregular.
Conclusiones: La disfonía es un hallazgo prevalente en adultos con EPOC, y el tabaquismo aparece como uno de los principales factores que contribuyen a su aparición. La revisión subraya el papel del tabaquismo como factor causal de la disfonía orgánica entre los individuos con EPOC.
Palabras clave: Disfonía, alteraciones vocales, tabaquismo, voz, EPOC.
Revisión Sistemática
Smoking as Cause of Organic Dysphonia Secondary to Chronic Obstructive Pulmonary Disease: A Systematic Review
Tabaquismo como causa de disfonía orgánica secundaria a enfermedad pulmonar obstructiva crónica: Una revisión sistemática
YERIS-ANDREINA CARRILLO-VERA yeris.carrillo@unipamplona.edu.co
ANDRÉS LLANOS-REDONDO andres.llanos@unipamplona.edu.co
DIEGO RIVERA-PORRAS drivera23@cuc.edu.co
Received: 19 October 2023
Accepted: 05 February 2024
The World Health Organization (WHO) has declared that smoking is a public health problem; this habit became popular in the last century and still persists today, smoking tobacco causes chemical and psychological addiction and can cause physiological changes 1. Thus, nicotine is one of the substances found in tobacco, producing addiction and significantly affecting the central nervous system, which is one of the most complex and important systems of the human body 2,3. Therefore, tobacco smoking damages most of the organs and systems of the body, decreasing the overall health of the person, as well as causing cancer of the lung, esophagus, larynx, mouth, kidney, liver, stomach, among others; as well as respiratory tract infections, COPD, chronic bronchitis and pneumonia 4,5.
Among the physiological changes caused by tobacco consumption are vocal alterations 6 and dysphonia, which is an alteration in vocal quality, where not only the acoustic qualities of the voice are affected, such as intensity, tone, timbre and duration, but also the anatomical part of the phonatory apparatus, causing an altered oral communication 7,8. Consequently, people suffering from dysphonia and voice disorders are more prone to develop social and communication problems, causing a decrease in the quality of life and in their physical and/or mental state 7,9,10.
On the other hand, COPD is mainly caused by tobacco consumption 11,12,13, and is defined as a common respiratory condition, which is mainly characterized by airflow limitation 7, this limitation hinders the process of expelling air from the lungs, which triggers difficulties to breathe properly 14,15. Dysphonia is a common finding in COPD 11,16, as constant coughing is a common symptom of this pathology, it can cause incomplete adduction of the vocal cords triggered by vocal fatigue, and it is usually perceived as shortness of breath 7.
Additionally, COPD can affect voice production directly, associated with respiratory impairment and decreased lung volume 17, and, indirectly, as a side effect of medication and associated with concurrent symptoms 1618. According to the American Speech-Language-Hearing Association, COPD symptoms such as shortness of breath, constant cough, and mucous, can cause alterations in the larynx and vocal cords causing voice problems 17.
In this context, people with COPD have a significantly higher rate of dysphonia 11,19; not only because of poor respiratory support, but also because of the use of inhaled corticosteroids (ICS) 16, symptoms associated with these diseases, such as cough, history of previous or current smoking, and common comorbidities of lung disease 11,20.
COPD is one of the 10 leading causes of morbidity and mortality in the adult population worldwide 21,22, its global prevalence is 11.4% in people aged 30 years or more 23; in Europe it has a prevalence of 9%, 11% in Latin America, 14.1% in North America, 8.6% in Japan, 10% in Asia, and 6% in the United States 24,25. In Mexico, it is also one of the 10 leading causes of morbidity and mortality; a review study found that 54-77% of patients with COPD of moderate severity were tobacco smokers, while 38-51% of those with very severe stages of the disease also smoked 2,26.
Similarly, the epidemiology of voice disorders among the general population is variable and has a high recurrence rate, approximately, 30% of adults have experienced a voice disorder during their lifetime and almost 7% report a current voice problem 27,28; in Sweden, 16.9% of adults experience a voice disorder, and 21.9% of adults in the United States also experience a voice disorder at some point in their lives 7,29,30. Likewise, the World Health Organization (WHO) reported that tobacco smoking causes the death of more than 5 million people each year and 70% of COPD deaths have smoking in common 2,31,32.
In accordance with the above and considering the arguments and findings previously revealed, the present paper aims to conduct a systematic review of the literature, thus, the following research question arises: Does smoking produce Organic Dysphonia in adults with COPD?
This review was conducted following the parameters proposed by the PRISMA statement, a tool that allowed the systematic review of the scientific literature based on the search and selection of research articles, providing updated guidance on the presentation of systematic reviews 33,34,35. To this end, the databases were initially identified and the key terms in the search for information were defined. The studies were selected on the basis of inclusion and exclusion criteria, which facilitated the evaluation of their quality and reliability and thus made it possible to answer the research question posed.
The PICO model was used to construct the research question, which constitutes a specialized format to develop the clinical question, describing the components that integrate it, allowing to improve the specificity and conceptual clarity of the clinical problems to be studied, as well as allowing the searches to have a higher quality and precision, which allows to collect pertinent and precise data to answer the problem question 36,37.
The classification of the quality of the evidence and grading of the strength of recommendation was performed through the GRADE system; this system is highly specialized for the scientific analysis of the most relevant studies for the present research 38,39. It is a web application for creating managing and sharing summaries of research evidence (called evidence profiles and summary of results table), such tables are often used to summarize evidence from systematic reviews, these tables present key information about the relevant outcomes for a given measured care question, such as the body of evidence, judgments about the underlying quality of evidence, key statistical findings, and a rating for the quality of evidence for each outcome 40,41.
In accordance with the topic posed for the research, the components of the PICO model shown in table 1 were established, resulting in the following research question: Does smoking produce Organic Dysphonia in adults with COPD?
Key terms were selected from the Descriptors in Health Sciences (DESC) and Medical Subject Headings (MESH) (see table 3).
A search strategy was developed with the help of databases, some of which are part of the digital library of the University of Pamplona, Colombia. Subsequently, search equations were designed with the terms found. These equations were created using logical AND/OR operators and symbols such as " and (). The information search was carried out in PUBMED, SPRINGER LINK, SCIENCEDIRECT, SCOPUS and EBSCO, using the English language (see table 4).
Initially, we classified the studies that were characterized by including tobacco consumption in adults with COPD, additionally, articles where the characteristics and effects of tobacco consumption on the voice as a cause of Organic Dysphonia in adults with COPD were shown, it was taken into account that these studies had characteristics and aspects such as: adult population with COPD, smoking history, manifestations of the population with respect to vocal and respiratory problems or alterations and thus give development to the research topic.
A preliminary selection of studies was considered, based on the established inclusion criteria, population characteristics, type of study and year. Subsequently, a registration table in Excel, prepared by the authors, was filled in independently, in which the key elements of each of the selected studies were specified. Following the structure proposed by the PRISMA statement, the process used in the identification, screening, eligibility and inclusion of articles is briefly described.
GRADE pro GDT was used through the clinical management question, including in the analysis number of studies, study design, risk of bias, inconsistency, indirect evidence, imprecision and the degree of certainty of the study (42).
The eligibility criteria were determined following the order established in the methodology, through the developme t of each of the phases of the PRISMA flowchart (figure).
The search was performed in the PUBMED, SPRINGER LINK, SCIENCEDIRECT, SCOPUS and EBSCO databases, according to the variable cross-references constructed from the DESC and MESH keywords. The following filters were then applied: document type, time window, full text or duplicate, and articles without access and non-compliance with criteria. Finally, articles were selected to obtain the final sample of 30 articles used in this research (see table 5).
The initial selection of the research articles was made by preliminary reading of the titles, abstracts, and, later, the introduction, which allowed the identification of the most relevant articles with respect to the topic under investigation, with a total of 30 articles selected. The results of each variable cross-checking in English are listed below (see table 6) for the five databases PUBMED, SPRINGER LINK, SCIENCEDIRECT, SCOPUS, and EBSCO.
Source: own elaboration.
In the first search, 43 cross-references were made in English, among the different variables, resulting in 3 articles in PUBMED, 10 articles in SPRINGERLINK, 7 articles in SCIENCEDIRECT, 8 articles in SCOPUS and 2 articles in EBSCO, for a total of 30 articles.
The classification of the quality of evidence and grading of the strength of recommendation was performed through the GRADE system, which was highly specialized for the scientific analysis of the studies included in this study. This resulted in a high level of moderate certainty (15 articles) and a high level of certainty (15 articles), thus demonstrating a high quality of evidence for each result and, in general, for the review carried out (see table 7).
The selection was made after reading the titles and abstracts of the articles and they were analyzed in their entirety with a complete reading, applying criteria that allowed a selection, thus obtaining those that gave an answer to the question posed. The selection corresponded to a final sample of 30 articles (see table 8).
Table 9 shows the effects caused and structures affected corresponding to Organic Dysphonia produced by tobacco consumption in adults with COPD.
Smoking is the leading cause of preventable death worldwide, and it is considered a public health problem. Tobacco smoke is made up of different toxic and carcinogenic compounds, including nicotine, nitrogen oxides and carbon monoxide 9.
Once nicotine is inhaled, it is absorbed and transmitted to the brain, where it acts on specialized receptors that cause the release of neurotransmitters, especially dopamine. The pleasurable effects of this neurotransmitter result in positive feedback that leads to addiction. 45 Continuing to smoke tobacco produces neuroadaptive tolerance, while quitting causes withdrawal symptoms, as well as irritability, anxiety and depression; in addition, the conditioned behaviors, i.e., the pleasure after a meal, developed by a smoker over the year serve as reinforcement to continue smoking tobacco. 45
Smoking is also an important factor that has a deleterious effect on vocal health 9, and it is considered one of the main causes of vocal disorders, 50 likewise, according to the International Union Against Cancer, tobacco smoking is considered the most important risk factor in the etiology of laryngeal cancer 12.
Changes in the anatomical structure of the larynx can cause functional problems and as a result, can adversely affect voice production and lead to voice disorders. 6 From a clinical/acoustic voice perspective, tobacco smoking has been shown to induce acoustic changes in characteristics such as fundamental frequency (FO), jitter, shimmer, harmonic-to-noise ratio (HNR), 48,57,7) brightness, maximum phonation time, pitch variation and sound quality, tense voice, throat clearing, changes in pitch quality and pitch variation, deterioration of voice quality and various degrees of dysphonia, 16,6,4 increased mucus production, leading to a choppy or raspy voice quality, vocal weakness and aphonia, 11,21 resulting in impaired oral communication.
It is widely known that voice disorders have a very high recurrence rate worldwide. Particularly, even if voice rehabilitation is performed after the onset of a disorder or disturbance, the risk of recurrence is even higher unless the risk factor that adversely affects it and causes its etiology is eliminated 6.
Regarding the structure of the vocal folds, it is stated that smoking tobacco causes chronic irritation and abnormal texture 46, edema, mainly in the superficial layers, presence of erythema, nodules and polyps in the vocal folds, 11,47 abnormalities in flexibility or stiffness, abnormalities of the size of the glottic space, resulting in microscopic alterations identified in the epithelium, and abnormal and swollen border 4, as well as Rheinke's edema, leukoplakia, glottic edema, abnormalities in flexibility or stiffness due to prolonged edema, increased vascularization of the vocal folds 16,46, inflammation, irritation and dryness in the vocal tract, 14,6 enlarged laryngeal mucosa, incomplete adduction of the vocal folds, 7 thickening, aberrations and carcinomas in the vocal fold epithelium, 46 acute laryngitis caused by an upper respiratory tract infection, laryngeal cancer, 17,11,12,6 likewise, tobacco favors the increase in the production of cells and change in the shape of the vocal folds, contributing to the appearance of vocal fold cancer. 1
Prolonged exposure of the laryngeal mucosa to tobacco compromises its mucoondulatory movement, chronic inflammation or irritation, benign and malignant tumors, 52 mucosal edema or interaritenoid thickening and modifies voice quality causing burning sensation, throat clearing and presence of secretions and laryngitis. 1 Likewise, a relationship between tobacco smoke exposure and different types of cancer, respiratory, cardiovascular, infectious and neurological diseases has been demonstrated 44.
Since voice production results from complex interactions between the respiratory and phonatory systems, tobacco smoking can result in a much more drastic loss of pulmonary function and dysphonia 17, which is characterized by respiratory as well as systemic and extrapulmonary manifestations that may be accompanied by various comorbidities such as heart failure, cardiac arrhythmias, anemia, weight loss, anxiety, depression, diabetes, increased muscle pain, wheezing, frequent coughing. 13
In addition to typical pulmonary symptoms such as dyspnea, increased mucus production, cough and decreased exercise capacity, in COPD, the voice can be affected by various symptoms of the disease, leading to diminished and choppy voice quality further affecting an individual's quality of life. 11,2 According to the American Speech-Language-Hearing Association, these and other symptoms of COPD can wreak havoc on the larynx and vocal cords, causing problems such as voice and communication disorders 17.
COPD can affect voice quality and production, both directly, associated with respiratory impairment, and indirectly, as a side effect of medication and associated with concurrent symptoms, contributing to dysphonia. 16 Similarly, individuals show limited ventilatory capacity and respiratory infections 21,58,59,43,51 with the consequent increase in respiratory frequency, which can compromise communication and decrease the Maximum Phonation Time, 49 causing COPD subjects to need numerous air refills to maintain and finish the sentence during conversation 9.
This being the case, pulmonary disorders cause limitation of vital capacity, which in turn will limit the respiratory support and control needed to speak effectively. 54 Adequate prevention of controllable diseases such as COPD through early smoking cessation and early intervention for patients who develop these diseases will play an important role in maintaining vocal strength and efficiency 17. Dysphonia can be directly related to alterations in airflow volume and velocity, so the decreased lung volume associated with COPD 55 and common dyspnea contribute to dysphonia and reduce message duration, resulting in decreased vocalization efficiency 17.
In contrast to other controversial interventions for the treatment of COPD, tobacco smoking cessation may be the most effective therapeutic intervention. It has been estimated that nearly one in five deaths can be attributed to the effects of smoking, and smoking remains the greatest risk factor for developing COPD. Quitting tobacco smoking is difficult, both, because of the addictive properties of nicotine, and the psychological dependence it causes 45.
Dysphonia is a common finding in adults with COPD, smoking being the main cause of their appearance.
Smoking affects the larynx and vocal cords causing notable alterations, such as irritation and enlargement of the laryngeal mucosa, benign and malignant tumors, increased vascularization, inflammation and dryness, edema, nodules, polyps and erythema in the vocal cords. Each of these manifestations affects not only the structures involved in the voice process, but also the acoustic characteristics of the voice, causing changes in tone quality and pitch variation, deterioration of voice quality, and various degrees of dysphonia.
Similarly, COPD can affect the quality and production of the voice, associated with respiratory impairment, these people may present difficulties in the voice, since phonation requires considerable respiratory capacity and as one of the main symptoms of COPD is the limitation and obstruction of expiratory airflow, leading to an imbalance between breathing and phonation, as well as decreased lung volume and dyspnea, contributing to dysphonia and reduce the duration of the message, resulting in a decrease in the efficiency of vocalization.
*Correspondencia: Diego Rivera-Porras. drivera23@cuc.edu.co
