Introduction
Teachers rely on their voice for their professional activities, which classifies them as voice professionals1. Through their voice, they convey knowledge and teachings in classrooms, requiring prolonged and continuous use. In Mexico, teachers working in basic education typically use their voice five days a week for 3 to 8 hours per day, which amounts to 15 hours per week in preschool, 22.5 in elementary school, and 30.5 in secondary school2.
Prolonged voice use, along with environmental factors, habits, organic causes, and vocal misuse and abuse3,4, leads to functional dysphonia or voice impairment caused by improper coordination of the elements involved in voice production. This includes anatomical and functional aspects of the larynx and the respiratory and resonating systems4. Clinically, these patients may exhibit noticeable effort to produce sounds, difficulty maintaining the voice, vocal fatigue, pitch variation, throat clearing, or loss of volume4.
Various studies have reported alterations in the voice quality and characteristics of teachers3,5–17, placing them at high risk of developing chronic laryngitis, vocal cord injuries, and dysphonia. The objective of this study was to determine the relationship among voice perception, vocal symptoms, and risk factors in female teachers of basic education.
Method
We conducted a cross-sectional, descriptive, and correlational study from February through December 2019. A total of 152 teachers were recruited from public schools in the Tlalpan Borough of Mexico City, Mexico. Eligibility criteria included: a) being female (while male participation was considered, it was < 5%, and to avoid bias, only women were included); b) aged 20 up to 70; c) being an active teaching professional; and d) having no self-reported disease affecting the phonation organ.
Data mining
The Voice Handicap Index (VHI-30) inventory, a questionnaire that quantifies the self-perceived impact of a voice disorder on vocal function, physical capacity, and emotions related to dysphonia18, was used. Additionally, a 15-question survey was developed to gather demographic data (age, work tenure, level of teaching), self-reported vocal symptoms (frequent throat dryness, frequent dysphonia, frequent aphonia, aphonia at the end of the workday, frequent vocal effort, frequent vocal effort in class, concern about voice quality, perception that voice quality affects personal and work life, frequent gastroesophageal reflux, history of phoniatric care), and habits (smoking, alcohol consumption). Each teacher was provided with a printed copy of both questionnaires and asked to complete all the questions.
Data analysis
We performed the descriptive analysis obtaining means, standard deviations, frequencies, and percentages for demographic characteristics, symptoms, habits, and the VHI-30 subscales. Inter-group differences were analyzed using ANOVA and Kruskal-Wallis tests. Associations across variables were determined using the chi-square test and Spearman’s correlation coefficient. The analysis was conducted using SPSS Statistics v.26, with a significance level set at p ≤ 0.05.
Ethical responsabilities
The protocol was approved by an institutional research and ethics committee at a tertiary referral center in Mexico City (No. 38/19). Participants signed informed consent and authorized the use of their data.
Results
The participants’ mean age was 38.9 years (standard deviation [SD], 0.4; range, 21-62), with a mean teaching tenure of 15.6 years (SD, 10.6; range, 1-40). The levels of teaching were elementary school (53.9%), secondary school (30.3%), and preschool (15.8%). Regarding habits, 17.8% reported smoking, 46.1% reported social alcohol consumption, and 2% reported risky alcohol consumption.
The VHI-30 revealed that 90.1% had physical disability; 82.9%, functional disability, and 57.9%, emotional disability. Regarding severity, 81.6% had mild disability; 15.1%, moderate disability; 3.3%, severe disability. The average total score was 18.6 (SD: 16.7).
The most frequently reported symptoms were frequent vocal effort in class (82.9%), frequent throat dryness (68.4%), and frequent dysphonia (64.5%) (Table 1).
Table 1. Self-reported symptoms
| Symptom | % |
|---|---|
| Frequent throat dryness | 68.4 |
| Frequent dysphonia | 64.5 |
| Frequent aphonia | 62.5 |
| Frequent vocal effort | 48.7 |
| Aphonia at the end of the workday | 50.0 |
| Frequent vocal effort in class | 82.9 |
| Concern about voice quality | 59.2 |
| Frequent gastroesophageal reflux | 47.4 |
| Perception that voice quality affects personal and work life | 55.3 |
| History of phoniatric care | 5.9 |
Chi-square testing showed a significant difference (p < 0.05) between teaching level and frequent vocal effort in class, alcohol consumption, and tobacco use. Alcohol consumption was associated with frequent aphonia and aphonia at the end of the workday, while tobacco use was associated with emotional disability. The most moderate positive correlations were found between frequent throat dryness and frequent dysphonia (rho: 0.59; p < 0.01), concern about voice quality (rho: 0.44; p < 0.01), and frequent gastroesophageal reflux (rho: 0.41; p < 0.01). Frequent dysphonia was correlated with frequent gastroesophageal reflux (rho: 0.41; p < 0.01). Aphonia at the end of the workday was correlated with concern about voice quality (rho: 0.47; p < 0.01), and concern about voice quality was correlated with the perception that voice quality affects personal and work life (rho: 0.47; p < 0.01). Weak positive correlations were found between age and a history of phoniatric care (rho: 0.16; p < 0.05), years of tenure with frequent aphonia (rho: 0.19; p < 0.05), and frequent gastroesophageal reflux (rho: 0.18; p < 0.05) (Table 2).
Table 2. Correlation Matrix of self-reported symptoms
| Symptom | Throat Dryness | Dysphonia | Aphonia | Frequent vocal effort | Aphonia at end of day | Frequent vocal effort in class | Concern about voice | Reflux | Phoniatric care | Voice affects personal and work life |
|---|---|---|---|---|---|---|---|---|---|---|
| Throat Dryness | 1 | |||||||||
| Dysphonia | 0.59* | 1 | ||||||||
| Aphonia | 0.20† | 0.36* | 1 | |||||||
| Frequent vocal effort | 0.25* | 0.39* | 0.31* | 1 | ||||||
| Aphonia at end of day | 0.36* | 0.29* | 0.29* | 0.39* | 1 | |||||
| Frequent vocal effort in class | 0.33* | 0.35* | 0.22* | 0.38* | 0.39* | 1 | ||||
| Concern about voice | 0.44* | 0.37* | 0.32* | 0.36* | 0.47* | 0.35* | 1 | |||
| Reflux | 0.41* | 0.41* | 0.34* | 0.28* | 0.30* | 0.32* | 0.29* | 1 | ||
| Phoniatric care | 0.05 | 0.03 | 0.03 | 0.02 | -0.02 | 0.04 | 0.22* | 0.03 | 1 | |
| Voice affects personal and work life | 0.39* | 0.28* | 0.25* | 0.30* | 0.34* | 0.38* | 0.47* | 0.29* | 0.15 | 1 |
|
* Significance (p) < 0.01. † Significance (p) < 0.05 |
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Teaching tenure
The sample was categorized into 4 groups based on teaching tenure. Group A (n = 67) had 1–10 years of tenure (mean, 6.1, SD: 3), Group B (n = 36) had 11–20 years (mean, 4.8, SD: 2.5), Group C (n = 30) had 21–30 years (mean, 25.7; SD, 2.7), and Group D (n = 19) had 31–40 years (mean, 34.5; SD, 2.8).
Tobacco use was found in 19.4% of Group A, 22.2% of Group B, 6.7% of Group C, and 21.1% of Group D. Regarding alcohol consumption, 4.5% of Group A reported risky consumption, while 55.2% reported social consumption. Social consumption was also reported by Group B (47.2%), Group C (33.3%), and Group D (31.6%). No significant differences were found between groups for alcohol and tobacco consumption. Analysis of VHI-30 results showed that mild vocal disability predominated in all four groups: Group A (83.6%), Group B (86.1%), Group C (63.3%), and Group D (94.7%). Moderate disability was most prevalent in Group C (30%), followed by Group B (13.9%), Group A (11.9%), and Group D (5.3%). Severe disability was only found in Groups A (4.5%) and C (6.7%). Significant inter-group differences were found (p < 0.05).
The most frequently self-reported symptom was frequent vocal effort in class in Groups A (85.1%), B and C (83.3%), followed by frequent throat dryness in Group C (80%), Group B (69.4%), and Group A (62.7%). In Group D, the most common symptoms were frequent dysphonia (84.2%) and frequent aphonia (73.7%). A significant difference was found between groups for a history of phoniatric care (Table 3).
Table 3. Self-reported symptoms by tenure
| Symptom | Group A (%) | Group B (%) | Group C (%) | Group D (%) | p* |
|---|---|---|---|---|---|
| Frequent throat dryness | 62.7 | 69.4 | 80.0 | 68.4 | 0.421 |
| Frequent dysphonia | 58.2 | 63.9 | 66.7 | 84.2 | 0.575 |
| Frequent aphonia | 55.2 | 66.7 | 63.3 | 78.9 | 0.123 |
| Frequent vocal effort | 46.3 | 44.4 | 60.0 | 47.4 | 0.384 |
| Aphonia at the end of the workday | 52.2 | 52.8 | 53.3 | 31.6 | 0.449 |
| Frequent vocal effort in class | 85.1 | 83.3 | 83.3 | 73.7 | 0.134 |
| Concern about voice quality | 59.7 | 63.9 | 60.0 | 47.4 | 0.660 |
| Frequent gastroesophageal reflux | 37.3 | 55.6 | 56.7 | 52.6 | 0.433 |
| Perception that voice quality affects personal and work life | 53.7 | 61.1 | 56.7 | 47.4 | 0.640 |
| History of phoniatric care | 1.5 | 8.3 | 16.7 | – | 0.017† |
|
* Value calculated for Kruskal-Wallis. † p < 0.05 |
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Chi-square tests showed significant differences (p < 0.05) in Group A between alcohol consumption and frequent aphonia, and aphonia at the end of the workday. In Group B, alcohol consumption was associated with frequent aphonia, aphonia at the end of the workday, and frequent vocal effort, as well as between teaching level and the perception that voice quality affects personal and work life. In Group C, alcohol consumption was associated with frequent gastroesophageal reflux, and in Group D, alcohol consumption was associated with frequent throat dryness and the perception that voice quality affects personal and work life.
Correlation analysis in Group A revealed a moderate positive relationship between years of tenure and frequent gastroesophageal reflux (rho: 0.34; p < 0.05).
Teaching performance Level
Three groups were formed based on teaching level: Group A (n = 24) consisted of preschool teachers, Group B (n = 82) included elementary school teachers, and Group C (n = 46) included secondary school teachers. Tobacco use was most common in Group A (25%), followed by Group B (15.9%) and Group C (6.7%). For alcohol consumption, 3.5% of Group B reported risky consumption and 47.6% reported social consumption. Social consumption was also reported by 45.8% of Group A and 43.5% of Group C. No significant differences were found between groups for any habit.
In VHI-30 results, severe disability (6.1%) was found only in Group B. Moderate disability was most common in Group C (17.4%), followed by Group B (17.1%) and Group A (4.2%). Mild disability was most frequent in all groups: 95.8% in Group A, 82.6% in Group C, and 76.8% in Group B. No significant inter-group differences were ever found.
The most frequently self-reported symptoms were frequent vocal effort in class (75%), frequent throat dryness (66.7%), and frequent dysphonia (66.7%) in Group A; frequent vocal effort in class (84.1%) and frequent throat dryness (72%) in Group B; and frequent vocal effort in class (84.8%) and frequent aphonia (67.4%) in Group C. No significant inter-group differences were ever found (Table 4).
Table 4. Self-reported symptoms by teaching performance level
| Symptom | Group A (%) | Group B (%) | Group C (%) | p* |
|---|---|---|---|---|
| Frequent throat dryness | 66.7 | 72.0 | 63.0 | 0.157 |
| Frequent dysphonia | 66.7 | 65.9 | 60.9 | 0.413 |
| Frequent aphonia | 45.8 | 64.9 | 67.4 | 0.243 |
| Frequent vocal effort | 33.3 | 54.9 | 45.7 | 0.067 |
| Aphonia at the end of the workday | 58.3 | 51.2 | 43.5 | 0.684 |
| Frequent vocal effort in class | 75.0 | 84.1 | 84.8 | 0.562 |
| Concern about voice quality | 54.2 | 58.5 | 63.0 | 0.869 |
| Frequent gastroesophageal reflux | 37.5 | 51.2 | 45.7 | 0.211 |
| Perception that voice quality affects personal and work life | 58.3 | 53.7 | 56.5 | 0.637 |
| History of phoniatric care | 4.2 | 6.1 | 6.5 | 0.929 |
|
* Value calculated for Kruskal-Wallis. |
||||
When performing the chi-square test, a significant difference (p < 0.05) was found in Group A between tobacco use and alcohol consumption, and between alcohol consumption and frequent laryngeal dryness. In Group B, a significant difference was found between alcohol consumption and frequent hoarseness, as well as concern about voice quality. In Group C, a significant difference was found between tobacco use and alcohol consumption, and between alcohol consumption and the perception that voice quality affects personal and work life.
The correlation analysis showed a moderate and positive association in Group A between age and frequent gastroesophageal reflux (rho: 0.42; p < 0.05), between years of experience and frequent laryngeal dryness (rho: 0.40; p < 0.05), and between years of experience and frequent gastroesophageal reflux (rho: 0.47; p < 0.05). In Group B, a weak correlation was found between age and history of phoniatric care (rho: 0.23; p < 0.05). In Group C, a correlation was found between years of experience and frequent vocal strain in class (rho: –0.37; p < 0.01).
Age of Participants
Four groups were created based on age: Group A (n = 28) included teachers aged 20 to 29 years; Group B (n = 59) included teachers aged 30 to 39 years; Group C (n = 34), teachers aged 40 to 49 years; and Group D (n = 31) teachers aged 50 to 62 years.
Tobacco use was present in 20.6% of Group C, 17.9% of Group A, 16.9% of Group B, and 16.1% of Group D. Alcohol consumption was reported as risky in 3.6% of Group A and 3.4% of Group B. Social alcohol consumption was found in 52.9% of Group C, 50% of Group A, 49.2% of Group B, and 29% of Group D. No significant inter-group differences were ever found.
The results of the VHI-30 showed severe vocal disability in 5.1% of Group B, 3.2% of Group D, and 2.9% of Group C, and moderate disability in 17.6% of Group C, 15.3% of Group B, 14.3% of Group A, and 12.9% of Group D. No significant inter-group differences were ever found.
The most frequently self-reported symptoms by Groups A, B, and C were frequent vocal strain in class (82.1%, 82.8%, and 94.1%) and frequent laryngeal dryness (60.7%, 65.5%, and 79.4%), with Group C being the most affected in both cases. Group D reported frequent dysphonia as the main symptom (80.6%), followed by frequent aphonia (71%), frequent vocal strain in class (71%), and frequent laryngeal dryness (67.6%). No significant differences were found between the groups (Table 5).
Table 5. Self-reported symptoms by age
| Symptom | Group A (%) | Group B (%) | Group C (%) | Group D (%) | p* |
|---|---|---|---|---|---|
| Frequent throat dryness | 60.7 | 65.5 | 79.4 | 67.6 | 0.684 |
| Frequent dysphonia | 60.7 | 55.2 | 67.6 | 80.6 | 0.341 |
| Frequent aphonia | 46.4 | 63.8 | 64.7 | 71.0 | 0.160 |
| Frequent vocal effort | 42.9 | 48.3 | 52.9 | 48.4 | 0.910 |
| Aphonia at the end of the workday | 53.6 | 51.7 | 61.8 | 32.3 | 0.349 |
| Frequent vocal effort in class | 82.1 | 82.8 | 94.1 | 71.0 | 0.197 |
| Concern about voice quality | 57.1 | 60.3 | 67.6 | 51.6 | 0.790 |
| Frequent gastroesophageal reflux | 25.0 | 51.7 | 58.8 | 48.4 | 0.063 |
| Perception that voice quality affects personal and work life | 53.6 | 51.7 | 64.7 | 51.6 | 0.147 |
| History of phoniatric care | 3.6 | 1.7 | 8.8 | 12.9 | 0.456 |
|
* Value calculated for Kruskal-Wallis. |
|||||
Chi-square test revealed significant differences (p < 0.05) in Group A between tobacco use and alcohol consumption, and between alcohol consumption and overall vocal disability; between teaching level and tobacco use, and between alcohol consumption and the perception that voice affects personal and work life. In Group B, significant differences were found between tobacco use and alcohol consumption, emotional disability, and dysphonia at the end of the workday; between alcohol consumption and frequent aphonia, and between alcohol consumption and dysphonia at the end of the workday. In Group C, significant differences were found between teaching level and frequent aphonia, and between tobacco use and concern about voice quality. In Group D, significant differences were found between alcohol consumption and aphonia at the end of the workday, and between alcohol consumption and the perception that voice quality affects personal and work life.
Correlation analysis showed in Group A a moderate negative association between age and emotional disability (rho: –0.49; p < 0.01), a moderate positive association between age and frequent vocal strain in class (rho: 0.40; p < 0.05), and a positive association between years of work experience and frequent vocal strain in class (rho: 0.43; p < 0.05). In Group C, moderate positive associations were found between age and functional disability (rho: 0.37; p < 0.05), and between age and overall disability (rho: 0.38; p < 0.05). Finally, in Group D, a moderate negative association was found between years of work experience and history of phoniatric care (rho: –0.47; p < 0.05).
Discussion
The study shows that female basic education teachers in Mexico City exhibit varying degrees of vocal disability, along with a series of self-reported symptoms and habits associated with voice problems. These findings provide evidence of a lack of knowledge related to vocal care and strategies for maintaining good vocal health, which would help prioritize voice preservation as the primary tool in their professional activities.
A total of 100% of the teachers showed some degree of vocal disability, which is higher than the rate reported in studies indicating high prevalences6–17,19. The mean score obtained on the VHI-30 was 18.6%, lower than that the on obtained in a study of preschool and primary teachers (23.5%)19 and higher than the one reported for basic education teachers (15.4%)7. In this context, China reported a prevalence of vocal disability of 59.7%16 and 47.5%9, while Cyprus reported a 69.9% rate20 for preschool and primary education teachers.
In this study, preschool and secondary education teachers primarily reported mild and moderate disabilities, whereas primary level teachers exhibited all 3 degrees of disability. This finding contrasts those of the report by Gavica-Vásquez et al. (2020), which states that teachers from preschool to high school primarily present mild disability10.
Of note that the group with the most years of tenure (31 to 40 years) was predominantly in the mild disability category (94.7%), while 4.5% of those with fewer years of experience exhibited severe disability. This finding is somewhat inconsistent, as one would expect the group with more years of service to show higher levels of severe disability, and the group with less tenure, being new to teaching, to have fewer severe cases. In this regard, it seems pertinent to revisit the suggestion by Cantor-Cutiva et al.21 who found similar results and suggested that teachers with more years of experience become accustomed to perceiving fatigue or voice problems as normal and part of their job. Conversely, Chen et al.22 reported that teachers within their first 3 years of teaching were more frequently diagnosed with voice disorders. Authors suggest that a possible explanation to this is that novice teachers tend to use incorrect phonation methods and, with time and accumulated experience, make adjustments, somewhat reducing vocal disease.
Regarding age, it is surprising that the oldest group reported mild disability, which is similar to that of the youngest group. The trend in vocal disability by tenure differs from what has been reported in the literature10, as in our study, teachers with less tenure were in the severe disability category along with those with 21 to 30 years of experience. We also found indications that both age (starting at 30 years old) and tenure (11 to 20 and 31 to 40 years) are risk factors, as moderate and severe disability cases were observed, which is similar to what has been reported in other studies13,14.
We found that alcohol consumption was higher among our participants compared to reports from teachers in Colombia3, Spain7, and Ecuador10. In this study tobacco use was higher than reported in basic education teachers10,12 and lower than in higher education teachers in Spain7, with 15.9% of primary teachers and 6.7% of secondary teachers being smokers. This result contrasts with a study in which secondary teachers were significantly more likely to smoke than primary teachers11.
In this study, the most reported symptoms were frequent vocal effort in class, throat dryness, dysphonia, and aphonia. Tenure, frequent dysphonia, and frequent aphonia were present only in the group with the highest number of years in teaching. Regarding age, the 2 oldest groups reported frequent dysphonia and aphonia as primary symptoms. These results are consistent with those reported by literature on frequent aphonia, dysphonia, throat dryness3,5,14–17,19,23, vocal effort5,6,19, vocal fatigue6,16,19,23,24, and gastroesophageal reflux5,25 as the most reported symptoms.
Alcohol consumption was associated with tobacco use, frequent aphonia, aphonia at the end of the workday, frequent gastroesophageal reflux, frequent throat dryness, frequent vocal effort in class, concern about voice quality, and the perception that voice quality affects personal and work life. On the other hand, tobacco use was associated with dysphonia at the end of the workday and the perception that voice quality affects personal and work life. In this regard, some studies reported no association between alcohol and tobacco use with vocal symptoms; however, they noted that these habits were infrequent among their participants3,12. Other studies have found that both active and passive smoking are associated with hoarseness5 and that smoking and alcohol consumption relate to vocal disability outcomes in the VHI-3010.
Correlation analysis revealed significant associations, with the strongest indicating that greater frequent throat dryness is associated with greater frequent dysphonia, greater concern about voice quality, and greater frequent gastroesophageal reflux. Additionally, greater frequent dysphonia is associated with greater frequent gastroesophageal reflux, and greater aphonia at the end of the workday is associated with greater concern about voice quality. Greater concern about voice quality is, in turn, associated with a higher perception that voice quality affects personal and work life. Considering teaching performance, for preschool teachers, greater age is associated with greater frequent gastroesophageal reflux, and greater tenure is associated with greater throat dryness and greater frequent gastroesophageal reflux. For primary teachers, greater age is associated with greater frequent aphonia, and for secondary teachers, greater tenure is associated with greater frequent vocal effort in class. Regarding age in the A group (20 to 29 years), greater age is associated with greater frequent vocal effort in class. In the C group (40 to 49 years), greater age is associated with greater functional disability, and in the D group, greater tenure is associated with fewer phoniatric care visits. It is noteworthy that correlations with vocal disability were also found, particularly in Group C, where greater age was associated with greater functional and global disability.
It is also observed that tobacco use is associated with emotional and global disability, that alcohol consumption is associated with symptoms, primarily frequent aphonia, and that teaching level is associated with the perception that voice affects personal and work life and with frequent aphonia. Conversely, tenure is related to frequent gastroesophageal reflux, frequent aphonia, frequent throat dryness, and frequent vocal effort in class, while age is related to a history of phoniatric care, frequent gastroesophageal reflux, emotional disability, and global disability.
Contrary to the study of Mieles12, although we did not find a correlation between self-reported symptoms and vocal disability, we did find correlations between age and emotional disability. Literature identifies gastroesophageal reflux as a risk factor, which was frequent in this study and is associated with hoarseness5. Additionally, contrary to findings reported in the literature, we found that tenure is associated with self-reported vocal symptoms5,14.
Some authors agree that few teachers seek professional or specialized care for voice-related difficulties5,26 and that they even hesitate between seeking help, treating the problem themselves, or ignoring it26. It has also been reported that teachers often continue working despite having symptoms that clearly indicate a voice problem22. In this study, the low frequency with which teachers seek phoniatric care is evident. Of note that we found a weak correlation between age and a history of phoniatric care and a moderate negative correlation between tenure and a history of phoniatric care, which is consistent with literature reporting teachers’ lack of interest in addressing their voice problems, likely due to insufficient or non-existent education on voice care and the minimization of symptoms.
The literature makes significant contributions regarding the level of teaching performance and is consistent with the fact that basic education teachers exhibit greater vocal disability at various degrees of severity8. This study found that primary school teachers exhibit greater severity, which is consistent with some research indicating that primary school teachers have a higher prevalence and likelihood of developing voice disorders9,16. It has been suggested that this may be due to the fact that in this educational level, work environments are noisier and students are more challenging to manage behaviorally, leading teachers to raise their voice volume, resulting in misuse and abuse5,17.
This study involved only women, and the results show a 100% prevalence of voice disorders. This finding is explained by abundant information in the literature, which identifies female sex as a risk factor for developing voice problems not only in teachers11,15,17,19,22,25,27,28. Notably, structural differences in laryngeal anatomy are highlighted, such as women having a smaller larynx19,28, shorter vocal cords11,17, with less tension (requiring more effort to maintain a specific pitch)22, and a lower concentration of hyaluronic acid9,28 (important for healing wounds and absorbing impact on the vocal cords)11,22, which predisposes them to injuries and scarring22, along with a tendency for increased voice use and adjustment17,28 due to situational demands17.
Conclusions
Age, tenure, teaching performance level, and alcohol consumption are associated with self-reported vocal symptoms and vocal dysfunction. Additionally, age and tobacco consumption are associated with emotional and global disability on the VHI-30 among female teachers in Mexico City.
Funding
The authors declare that they have not received funding.
Conflicts of interest
The authors declare no conflicts of interest.
Ethical disclosures
Protection of human subjects and animals in research. Protection of human and animal subjects. The authors declare that no experiments were performed on humans or animals for this study.
Confidentiality of data. The authors declare that no patient data appear in this article.
Right to privacy and informed consent. The authors declare that no patient data appear in this article.
Use of artificial intelligence for generating text. The authors declare that they have not used any type of generative artificial intelligence for the writing of this manuscript, nor for the creation of images, graphics, tables, or their corresponding captions.
