Keywords
epidemiology - voice - voice disorders - speech, language and hearing sciences
Introduction
Even though the speech-language pathologist (SLP), with voice professionals, has developed
more effective proposals for health promotion from the end of the 20th century onward,
he remains focused on the rehabilitation of a small group of individuals, setting
aside issues pertaining to a more collective setting, health promotion, and prevention
of voice disorders. Therefore, this professional is distanced from the epidemiological
principles that, especially in this situation, should be his main setting for work
and study. Population studies that aim to determine the vocal profile and general
health states of a population are still recent in the field of speech-language pathology.
These studies subsidize prevention measures for voice disorders, and are therefore
extremely important in order to plan collective health measures. For this reason,
it is necessary to conduct epidemiological studies in this field to structure speech-language
pathology practices in possible health measures.
According to a previous study[1], the prevalence of vocal symptoms should be perceived as an indication of a suspected
voice disorder. Among possible vocal symptoms, the ones most commonly observed in
dysphonic individuals are hoarseness[2] and vocal fatigue[3], and investigations should be carried out if these occur in isolation. Sore throat
and phlegm are also mentioned in the literature, as follows.
An epidemiological study was conducted in Finland[4]. In this study, 226 education students completed a questionnaire to determine the
occurrence of vocal problems in this population. The findings revealed that 34% of
respondents reported vocal problems. The symptoms most commonly mentioned were vocal
fatigue, hoarseness, and sore throat.
In Brazil, a population of 451 individuals was observed during the National Voice
Week Campaign of 1999[5]. The data showed that 58% of the population mentioned hoarseness, and that 24% of
individuals mentioned a sore throat.
Otorhinolaryngological symptoms were investigated in a study of 293 schoolchildren
aged between 7 and 14 years[6], and the findings revealed that 9% of the children mentioned hoarseness, albeit
this being less frequent than that in previous studies.
Therefore, it was observed that vocal symptoms are present in different populations
independently of age group or occupation. Thus, the aim of the present study was to
characterize the presence of vocal symptoms and their possible causes in a group of
college students and to analyze the association of some of these symptoms (hoarseness,
vocal fatigue, sore throat, and phlegm) to the possible causes reported by the students.
Method
The Research Ethics Committee of the institution approved this epidemiological cross-sectional
study under approval number 0045/2004, and all subjects signed an informed, free consent
form.
The study was conducted at a private university in the city of São Paulo. This environment
was chosen as it presented easy access to the studied population, and all the individuals
were in the same geographical area, had the same level of schooling, and theoretically,
at least similar social, economic, and cultural levels. All freshman students in 18
social science courses from the morning, afternoon, night, and full sessions were
invited to participate as volunteers in this study.
The age range for participants was set between 17 and 45 years of age. The lower limit
was considered to exclude vocal interferences of voice changing, and the upper limit
was defined thusly because of the several laryngeal alterations that may appear after
this age due to the effects of hormones, particularly in women[7].
The instrument used for data collection was an adapted questionnaire[8] composed of the following questions:
-
Sample characterization: Date of birth, age, course, period, year of starting college,
and date of questionnaire completion;
-
General health aspects: Self-perception of health compared to others of the same age,
current medical treatments, use of medication, and smoking;
-
Vocal aspects: Hoarseness, cough with secretion, lack of air, lower-pitched voice,
higher-pitched voice, high/low pitch variations in voice, weak voice, vocal strain/fatigue,
voice loss, dry cough, phlegm, sore throat, dry throat, dry mouth, difficulty swallowing,
voice breaks, strain when speaking, burning sensation when speaking—and possible causes
for these symptoms—intense vocal use, respiratory infections, stress, smoking, flu,
allergies, medications, digestive issues, among others.
The answers regarding respiratory infection, flu, and allergy were grouped into one
category (upper airway infections) as the studied population might have found it challenging
to differentiate these manifestations.
Before its definitive submission for completion, 13 evaluators, who were professionals
in different areas, analyzed the questionnaire, and then a pilot study was conducted
to make the necessary adjustments to the instrument. Students from 2 different majors
were chosen for this purpose: social sciences, as they were in 2 different classrooms
in the same period/semester, and speech-language pathology, as it was assumed that
the students of this major had at least partial knowledge of the questions in the
instrument. It should be noted that the students who participated in this phase of
the investigation and their questionnaire answers were excluded from the final result
analysis in the study.
For the purpose of data collection, the main researcher visited each classroom and
asked the lecturer for permission to administer the questionnaire. After obtaining
permission, 571 students volunteered to participate in the study, and received information
regarding the completion of the questionnaire. At the end of this procedure, they
each read and signed the informed, free consent form, which explained the aim and
provided information on the study. This was accomplished as a final step, as prior
knowledge about the specific study aims could have influenced their responses.
After collecting the completed questionnaires, the data were typed twice to eliminate
inadvertent mistakes. The statistical software used for data analysis was SPSS version
10.0 for Windows, and all analyses considered a descriptive level (p value) lower
than or equal to 5%.
The study population was characterized using proportions and measures of central tendency.
A chi-square test was used to verify the existence of statistical association between
the presence of each dependent variable reported by the studied population (hoarseness,
vocal fatigue, sore throat, and phlegm) with their possible causes.
Results
Of the 571 participating college students, 59.9% were women, with ages varying between
17.8 and 39.9 years (mean = 21.25 years).
Regarding self-perception of their general health states, most subjects classified
their state as good (54.1%) or excellent (29.9%). As far as the use of medication
went, 25.2% reported using some kind of medication, and this number was higher than
those who reported being in some kind of medical treatment (17%). Smoking was reported
by 30.5% of the studied population ([Table 1]).
Table 1.
Numerical (n) and percentage (%) distribution of individuals according to sex, age,
self-perception of general health state, medical treatment, use of medication, and
smoking
|
Variable
|
Category
|
n
|
%
|
|
Sex
|
Female
|
342
|
59.9
|
|
Male
|
229
|
40.1
|
|
Age
|
<21
|
397
|
69.5
|
|
>21
|
174
|
30.5
|
|
General health in
|
Excellent
|
171
|
29.9
|
|
relation to others
|
Good
|
309
|
54.1
|
|
Fair
|
79
|
13.8
|
|
Poor
|
12
|
2.2
|
|
Medical treatment
|
Yes
|
97
|
17.0
|
|
No
|
474
|
83.0
|
|
Use of medication
|
Yes
|
144
|
25.2
|
|
No
|
427
|
74.8
|
|
Smoking
|
Yes
|
174
|
30.5
|
|
No
|
397
|
69.5
|
|
Total
|
|
571
|
100.0
|
Regarding the occurrence of symptoms related to voice disorders, the symptoms most
frequently reported by the students were dry mouth (21%), dry throat (18.2%), phlegm
(17.9%), shortness of breath (15.2%), and hoarseness (15.9%). When declaring the possible
causes for the occurrence of these symptoms, those most frequently mentioned were
upper respiratory affections (39%), intense vocal use (24%), smoking (24%), and stress
(21.2%) ([Table 2]).
Table 2.
Numerical (n) and percentage (%) distribution of individuals according to reported
vocal symptoms and their possible causes.
|
Variable
|
Category
|
n
|
%[a]
|
|
Vocal symptoms
|
Dry mouth
|
120
|
21.0
|
|
Dry throat
|
104
|
18.2
|
|
Phlegm/secretion[b]
|
102
|
17.9
|
|
Shortness of breath
|
87
|
15.2
|
|
Hoarseness[b]
|
85
|
14.9
|
|
Cough with secretion
|
85
|
14.9
|
|
Dry cough
|
70
|
12.3
|
|
Vocal fatigue[b]
|
67
|
11.7
|
|
Sore throat[b]
|
61
|
10.7
|
|
Lower-pitched voice
|
49
|
8.6
|
|
Voice breaking
|
44
|
7.7
|
|
High/low-pitch varying voice
|
34
|
6.0
|
|
Voice loss
|
31
|
5.4
|
|
Vocal strain
|
22
|
3.9
|
|
Weak voice
|
24
|
4.2
|
|
Difficulty swallowing
|
24
|
4.2
|
|
Strong voice
|
13
|
2.3
|
|
Pain when speaking
|
9
|
1.6
|
|
Higher-pitched voice
|
4
|
0.7
|
|
Causes of symptoms
|
Upper respiratory affections
|
219
|
39.0
|
|
Intense vocal use
|
135
|
24.0
|
|
Smoking
|
135
|
24.0
|
|
Stress
|
119
|
21.2
|
|
Digestive issues
|
25
|
4.4
|
|
Pollution
|
20
|
3.5
|
|
Use of medication
|
14
|
2.5
|
|
Do not know
|
107
|
19.0
|
|
Other reason
|
82
|
14.7
|
|
No reason
|
30
|
5.3
|
a % In relation to the total sample (N = 571).
b Dependent variables in the present study.
In relation to the number of symptoms reported by each of the participating subjects,
it was verified that from the total, 38.4% reported 1 or 2 symptoms related to voice
disorders, while 27.6% mentioned more than 2 symptoms. Some of the subjects (34%)
reported that they did not perceive any vocal symptoms.
Regarding the number of different causes reported by each of the participating subjects,
more than half (57.6%) mentioned only one possible cause for the reported vocal symptom.
Regarding the analysis results of the association between the presence of hoarseness,
vocal fatigue, sore throat, and phlegm and their possible causes (intense vocal use,
smoking, upper airway affections, use of medication, digestive issues, and pollution)
([Table 3]), there was statistical significance between the presence of hoarseness and intense
vocal use (p < 0.001) and upper respiratory affections (p < 0.001). There was no significant
association between the presence of hoarseness and the following variables: stress
(p = 0.387), smoking (p = 0.663), use of medication (p = 0.155), digestive issues
(p = 0.309), and pollution (p = 0.532).
Table 3.
Numerical (n) and percentage (%) distribution of individuals according to the presence
of hoarseness, vocal fatigue, sore throat, and phlegm, and the causes attributed to
these symptoms.
|
Variable
|
Category
|
Ntotal
|
Hoarseness
|
Vocal fatigue
|
Sore throat
|
Phlegm
|
|
|
|
No
|
Yes
|
p
|
No
|
Yes
|
p
|
No
|
Yes
|
p
|
No
|
Yes
|
p
|
|
|
|
n (%)
|
n (%)
|
|
n (%)
|
n (%)
|
|
n (%)
|
n (%)
|
|
n (%)
|
n
|
|
|
Intense vocal use
|
Yes
|
135
|
90 (16,0)
|
45 (8,0)
|
< 0,001a
|
108 (19,2)
|
27 (4,8)
|
0,001a
|
114 (20,3)
|
21 (3,7)
|
0,044a
|
112 (19,9)
|
23 (4,1)
|
0,7
|
|
No
|
427
|
387 (68,9)
|
40 (7,1)
|
|
387 (68,9)
|
40 (7,1)
|
|
387 (68,9)
|
40 (7,1)
|
|
348 (61,9)
|
79 (14,1)
|
|
|
Stress
|
Yes
|
119
|
98 (17,4)
|
21 (3,8)
|
0,387
|
83 (14,8)
|
36 (6,4)
|
< 0,001a
|
101 (18,0)
|
18 (3,2)
|
0,092
|
92 (16,4)
|
27 (4,8)
|
0,148
|
|
No
|
443
|
379 (67,4)
|
64 (11,4)
|
|
412 (73,3)
|
31 (5,5)
|
|
400 (71,2)
|
43 (7,6)
|
|
368 (65,5)
|
75 (13,3)
|
|
|
Smoking
|
Yes
|
135
|
113 (20,1)
|
22 (3,9)
|
0,663
|
121 (21,5)
|
14 (2,5)
|
0,523
|
126 (22,4)
|
9 (1,6)
|
0,073
|
89 (15,8)
|
46 (8,2)
|
<0,001a
|
|
No
|
427
|
364 (64,8)
|
63 (11,2)
|
|
374 (66,5)
|
53 (9,5)
|
|
375 (66,7)
|
52 (9,3)
|
|
371 (66,0)
|
56 (10,0)
|
|
|
Upper respiratory affections
|
Yes
|
219
|
168 (29,9)
|
51(9,1)
|
< 0,001a
|
191 (34,0)
|
28 (5,0)
|
0,614
|
180 (32,0)
|
39 (7,0)
|
< 0,001a
|
156 (11,2)
|
63 (27,8)
|
<0,001a
|
|
No
|
343
|
309 (55,0)
|
34 (6,0)
|
|
304 (54,1)
|
39 (6,9)
|
|
321 (57,1)
|
22 (3,9)
|
|
304 (54,1)
|
39 (6,9)
|
|
|
Use of medication
|
Yes
|
14
|
10 (1,8)
|
4 (0,7)
|
0,155
|
10 (1,8)
|
4 (0,7)
|
0,052
|
13 (2,3)
|
1 (0,2)
|
0,651
|
11 (2,0)
|
3(0,5)
|
0,747
|
|
No
|
548
|
467 (83,1)
|
81 (14,4)
|
|
485 (86,3)
|
63 (11,2)
|
|
488 (86,8)
|
60 (10,7)
|
|
449 (79,9)
|
99 (17,6)
|
|
|
Digestive issues
|
Yes
|
25
|
23 (4,1)
|
2 (0,4)
|
0,309
|
17 (3,0)
|
8 (1,4)
|
0,002a
|
20 (3,6)
|
5 (0,8)
|
0,133
|
16 (2,8)
|
9 (1,6)
|
0,018a
|
|
No
|
537
|
454 (80,8)
|
83 (14,8)
|
|
478 (85,1)
|
59 (10,5)
|
|
481 (85,6)
|
56 (10,0)
|
|
444 (79,0)
|
93 (16,6)
|
|
|
Pollution
|
Yes
|
20
|
18 (3,2)
|
2 (0,3)
|
0,532
|
18 (3,2)
|
2 (0,3)
|
0,806
|
15 (2,6)
|
5 (0,9)
|
0,035a
|
17 (3,0)
|
3 (0,5)
|
0,734
|
|
No
|
551
|
468 (82,0)
|
83 (14,5)
|
|
486 (85,1)
|
65 (11,4)
|
|
495 (86,7)
|
56 (9,8)
|
|
452 (79,2)
|
99 (17,3)
|
|
Legend: a p < 0,050 (5%)
Regarding vocal fatigue, statistical significance was verified between the presence
of this symptom and intense vocal use (p = 0.001), stress (p < 0.001), and digestive
issues (p = 0.002). There was no significant association between the presence of vocal
fatigue and the following variables: smoking (p = 0.523), upper respiratory affections
(p = 0.614), use of medication (p = 0.052), and pollution (p = 0.806).
As far as the presence of sore throat went, there was a significant statistical association
between the presence of this symptom and intense vocal use (p = 0.044), upper respiratory
affections (p < 0.001), and pollution (p = 0.035). There was no association between
sore throat and stress (p = 0.092), smoking (p = 0.073), use of medication (p = 0.651),
and digestive issues (p = 0.133).
The statistical analysis results of the association between the presence of phlegm
and its possible causes revealed that there was a significant association between
presence of phlegm and smoking (p < 0.001), upper respiratory affections (p < 0.001),
and digestive issues (p = 0.018). There was no association with intense vocal use
(p = 0.700), stress (p = 0.148), use of medication (p = 0.747), and pollution (p = 0.734).
Discussion
The questionnaire was the instrument of choice for data collection in this study as
it has also been used in most studies with the same fundamental characteristics[9]
[10] and had the advantage of meeting the research aim in a rapid and brief manner.
With regard to the general health aspects, it is interesting to note that even though
most students considered their health satisfactory, part of the sample population
was undergoing medical treatment and/or using some type of medication. Furthermore,
the fact that the number of subjects taking some type of medication leads to the hypothesis
that these subjects were taking more than one medicine, or self-medicating.
Smoking, a habit also found among radio students and professionals[11], and in smaller numbers in a study concerning risk behaviors to the health of adolescents[12], is another factor that must be focused on and that represents preoccupying results,
since the studied population was composed of young adults who would be expected to
be in excellent health with low indexes of medical treatments and use of medication,
and without deleterious health habits.
As far as the vocal aspects went, more than half the subjects reported having at least
one vocal symptom during the month the data were collected. In a study conducted with
teachers, almost one-third of participants had an indication of voice disorder, as
they reported two or more vocal symptoms[1].
Upon the execution of the association analysis, it was possible to observe the relationship
between vocal symptoms of hoarseness, vocal fatigue, sore throat, and phlegm and the
causes that may account for these symptoms, as reported by the subjects.
The percentage of individuals that reported hoarseness was similar to that found in
another study with college students[4]. Other studies[13]
[14] have reported lower values than those obtained in the present investigation, perhaps
because the first study was conducted with a population from another country and who
had laryngeal disorders, and the second approached the symptoms using frequency indicators
(“often”, “sometimes”, “never”). Another study reported a higher percentage than that
in this research, possibly because they dealt with a population that could have had
laryngeal disorders, as it comprised individuals who sought assistance during the
1999 National Voice Week Campaign[5]. Similarly, higher values were also found for reported hoarseness among individuals
who took part in an event directed towards vocal health protection[15]. Another study with a higher hoarseness percentage had been conducted with a population
of industrial workers[16], and the findings are possibly due to the fact that the participants were subject
to environmental work risks that are deleterious to the voice, such as heat and dust.
The association analysis made it possible to state that intense vocal use and upper
respiratory affections, according to the interviewed subjects, influences the presence
of hoarseness.
The relationship between hoarseness and upper respiratory affections includes changes
in resonance and vocal projection, as there is an alteration in facial cavities. This
generates laryngeal strain as a compensation mechanism, which characterizes inadequate
vocal use. For some authors, vocal abuse was the main cause of hoarseness[7].
The presence of vocal fatigue is associated to intense vocal use[3]. When studying a group of teachers, the authors affirmed that intense vocal use
was the main cause of vocal fatigue, in addition to stress and digestive issues[17]. Vocal fatigue and the digestive problems mentioned by the college students in this
investigation, therefore, are responses to the initial state of stress in this population,
which may have been more evident as the data were collected towards the end of the
academic semester (November).
As with vocal fatigue, sore throat was present in subjects with vocal symptoms. The
obtained data were similar to the findings of a study with workers[16], and the percentage of reported sore throat was lower than that in a study with
a general population of park goers[14].
Regarding the association with the possible causes reported by the students, the presence
of sore throat was influenced by intense vocal use, upper respiratory affections,
and pollution. These findings are in accordance with those from studies that presented
a relationship between throat symptoms (sore throat being one of them) and intense
vocal use[18]. The upper respiratory affections may be related to the presence of acute laryngitis,
or caused by dryness of the vocal tract due to oral breathing, which may cause a sensation
of a sore throat[19]. In addition to upper airway affections, pollution also harms the body due to the
presence of carbon monoxide and other pollutants, increasing the incidence of upper
airway infections, cough, and throat irritation, among other effects[20]. Thus, these factors may directly affect the vocal tract.
The percentage of students who reported having phlegm was close to the value found
in another study[14]. Perhaps because subjects with different characteristics from those in this study
were analyzed, other authors reported lower values for the presence of phlegm than
that in the present study[16].
In the association analysis between the presence of phlegm and its reported causes,
this symptom is associated to smoking, upper respiratory affections, and digestive
issues. Smoking is a deleterious habit to the voice because the smoke from a tobacco
cigarette acts on the mucosa that lines the vocal tract and the vocal cords themselves.
Therefore, there is an increase in mucus secretion in order to protect this region[21]. The secretion, generated by allergic rhinitis, chronic or acute sinus infections,
or by gastroesophageal reflux, favors the habit of throat clearing, which is one of
the most commonly reported symptoms by individuals who have these affections[22].
Among the references mentioned in the present study, most, in at least one of the
vocal symptoms, reported different results (for more or for less) from that of the
present study. Therefore, as a sequel to this investigation, it would be interesting
to analyze in detail the vocal symptoms reported by the subjects; in other words,
observe if there is a direct manifestation of the disorder or a sign that would confirm
the reported symptom through a vocal assessment by an otorhinolaryngologist and an
SLP in order to confront and confirm the findings of this study.
A suggestion is that more studies in the field of voice be designed with a similar
theme to the present study. This way, it will be possible to establish reference values
for voice disorders and consequently subsidize future measures for collective health,
as well as to demonstrate the importance of the presence of SLPs in teams that plan
collective health measures, for example, those related to smoking, the environment,
and habits.
Conclusions
This study showed that intense vocal use, stress, digestive issues, pollution, upper
respiratory affections, and smoking are associated to vocal symptoms reported by college
students.
Therefore, it was confirmed that not only do health aspects and those directly related
to the voice interfere with its production, but also in the opinion of the studied
population, the external environment and habits interfere significantly in the appearance
of vocal symptoms.