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Causes of Tonsillar Disease and Frequency of Tonsillectomy Operations
Petri S. Mattila, MD;
Olli Tahkokallio, MD;
Jussi Tarkkanen, MD;
Janne Pitkäniemi, MSC;
Marjatta Karvonen, PhD;
Jaakko Tuomilehto, MD
Arch Otolaryngol Head Neck Surg. 2001;127:37-44.
ABSTRACT
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Objective To characterize the factors that influence the frequency of tonsillectomy
and adenoidectomy operations.
Design and Setting Nationwide questionnaire. Analysis of patients undergoing tonsillectomy
or adenoidectomy at Helsinki University Central Hospital, Helsinki, Finland.
Participants Four hundred eighty-three of 819 individuals randomly selected from
the Finnish National Public Registry. Two thousand two hundred thirty-one
individuals younger than 30 years who underwent tonsillectomy (888 patients),
adenotonsillectomy (294 patients), or adenoidectomy (1049 patients) at Helsinki
University Central Hospital from January 1, 1997, through December 31, 1998.
Main Outcome Measures Age of the individual at the time of operation. Indication for the operation.
Results The frequency of adenoidectomies was 24% (116 persons) and that of tonsillectomies
8% (39 persons) among the 483 individuals who returned the questionnaire.
The frequency of tonsillectomy operations by age was multimodal; the frequency
of tonsillectomies increased in preschool-aged children, declined thereafter,
and increased again in teenagers. Tonsillar hyperplasia was the most frequent
among children younger than 10 years, peritonsillar abscesses among teenagers,
and chronic tonsillitis among individuals older than 20 years. The proportion
of females was higher than males among teenaged patients. However, the cause
and sex distribution could not explain the multimodality in the age-specific
frequency. The age-specific frequency of tonsillectomies performed because
of peritonsillar abscesses still followed a multimodal distribution.
Conclusions Factors relating to respiratory tract infections, maturation of the
immune system, and the onset of puberty contribute to the cause of tonsillar
disease. Distinct indications for tonsillectomy should be defined for preschool-aged
children, teenagers, and individuals older than 20 years.
INTRODUCTION
ADENOIDECTOMY AND tonsillectomy operations are frequently performed
surgical procedures among children. The removal of the tonsils and the adenoids
is considered to be safe with no known long-term immunological side effects.
However, the plain presence of these organs in human beings suggests that
they may have provided an evolutionary advantage to humans. In this regard
knowledge of the epidemiology of tonsillar disease is important. First, such
data may be used to evaluate the cause of adenotonsillar disease. Second,
epidemiological data may be helpful in setting up clinical trials on the efficacy
of adenoidectomy and tonsillectomy. Third, it may be used in planning further
studies on the long-term effects and side-effects of adenoidectomy or tonsillectomy.
We report frequent indications for adenoidectomy and tonsillectomy operations
at different ages and evaluate the possible factors influencing the frequency
of tonsillar disease.
SUBJECTS AND METHODS
STUDY SUBJECTS
A questionnaire was sent to 819 Finnish individuals in 1998. These individuals
had previously served as a control population for children with diabetes mellitus
and they had been selected on the basis of sex and date of birth from the
Finnish National Population Registry matching 819 Finnish children with type
1 diabetes mellitus.1 The selection resulted
in a population that was a random representative of Finnish children except
for sex distribution (370 females, 449 males). The age of the individuals
ranged from 10 to 27 years when the questionnaire was distributed. Altogether
483 (59%) of the 819 forms were returned.
The questionnaire included the following questions: (1) Have your adenoids
been removed (adenoidectomy)? (2) If adenoidectomy was performed, at what
age was it done? (3) What was the reason for adenoidectomy? (I) ear infections,
(II) glue ear, (III) mouth breathing or snoring, (IV) sinusitis, or (V) other
infections. (4) Have you had tympanostomy tubes inserted? (5) If tympanostomy
was performed, at what age was it done? (6) Have your tonsils been removed
(tonsillectomy?) (7) If tonsillectomy was performed, at what age was it done?
The questions 1, 3 (I-V), 4, and 6 were followed by multiple-choice answer
fields including yes/no, and do-not-know choices. The questionnaire included
a picture with explanatory text showing the anatomical location of the adenoids
and tonsils to help the respondent to better understand the questions. Data
about the number of siblings, family income, location of the residence, and
type of day care was obtained from results of another questionnaire sent to
the same individuals during an earlier study.1
Data from the patient registry at the Helsinki University Central Hospital
(HUCH) was obtained by searching the database for the International
Classification of Diseases, 10th Revision (ICD-10) codes for tonsillectomy
(EMB10, 888 operations), adenotonsillectomy (EMB20, 294 operations), and adenoidectomy
(EMB30, 1049 operations) in the patient registry from January 1, 1997, through
December 31, 1998. Patients who were younger than 30 years were included for
the analysis. The indications for the operations were obtained from the ICD-10 code of the diagnosis of the patient when operated
on.
STATISTICAL ANALYSIS
Among the individuals who returned the questionnaire, the risk for adenoidectomy,
tympanostomy, or tonsillectomy within a given period, the incidence proportion
by age t, was estimated as a function of age:
,
where S(t) is the Kaplan-Meier
estimate of the survival probability. Statistical significance of the difference
between female and male subjects in the Kaplan-Meier estimate of the survival
probability was tested by the log rank test.
The nature of the age distribution of subjects was studied by testing
the goodness-of-fit and parameters for multimodal distribution models using
maximum likelihood methods with the MIX software package.2
The statistical procedure involved stepwise testing of a model distribution
of 1 standard distribution, subsequently a model distribution of 2 standard
distributions, thereafter a model distribution of 3 standard distributions,
and so on. Standard likelihood ratio test was performed comparing nested models
to establish a model that fitted the data adequately with the smallest number
of parameters. When there were too few observations the  2
test was used to test the goodness-of-fit. A multimodal distribution that
is a combination of 3 normal distributions has the following probability density
function:
.
This represents a mixture of overlapping normal distributions of variable x (age at the operation), with means µ1,
µ2, µ3, and SDs  1, 2, 3, and where  1 is the proportion
of the subjects in the first component, 2 the proportion
in the second, and (1 - a1 - 2) in
the third. The statistical significances of the independences between variables
in the tables of operation frequencies were tested using the 2
test and the Fisher exact test.
RESULTS
The frequencies of adenoidectomy, tympanostomy, and tonsillectomy operations
were estimated by a questionnaire sent to 819 individuals randomly selected
from the Finnish National Population Registry. Among the individuals who returned
the questionnaire, the frequency of adenoidectomy was 24% (116 persons); tympanostomy,
8% (39 persons); and tonsillectomy, 8% (39 persons) (Figure 1).
The frequency of tonsillectomies at distinct ages (age-specific frequency)
appeared to depict a multimodal distribution (Figure 1C). The rate of operations increased between the ages of
4 and 8 years, decreased thereafter, and increased again between the ages
of 13 and 23 years (Figure 1C).
To further investigate the age-specific frequency of tonsillectomies, the
patient registry at HUCH was analyzed for operations performed during 1997
and 1998. The distributions of the age-specific frequencies of tonsillectomies
performed at HUCH also showed an apparent multimodality for both female and
male subjects (Figure 2).
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Figure 2. Numbers of tonsillectomy and adenotonsillectomy
operations at Helsinki University Central Hospital during 1997 and 1998. Each
bar shows the number of operations performed on patients at a given age. The
numbers of tonsillectomy operations (without concurrent adenoidectomy) performed
on all patients are shown in Figure 2A. The numbers of tonsillectomy operations
performed on female and male patients are shown in Figure 2B-C, respectively.
The numbers of adenotonsillectomy operations (with concurrent adenoidectomy)
performed on all patients are shown in Figure 2D, and the numbers of adenotonsillectomy
operations performed on female and male patients are shown in Figure 2E-F,
respectively. In each figure part the curve for the best fitting mixture of
normal distributions is superimposed. Mixtures of normal distributions were
fitted in sequence of 1, 2, and 3 normal distributions. A combination of 3
normal distributions adequately fitted the observed age distribution of all
and female patients who had tonsillectomy or adenotonsillectomy (likelihood
ratio test: Figure 2A, 23= 28.7, P<.01;
Figure 2B, 23= 30.3, P<.01; Figure
2D, 23= 19.7, P<.01; and Figure
2E, 23= 19.6, P<.01. A combination
of 2 normal distributions adequately fitted the observed age distribution
of male patients who had tonsillectomy or adenotonsillectomy (likelihood ratio
test: Figure 2C, 23= 69.9, P<.01;
and Figure 2F, 23= 106.7, P<.01).
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A statistical analysis was carried out to test multimodality of the
distributions of the age-specific frequencies of operations performed at HUCH.
The distributions of age-specific frequencies of both tonsillectomy and adenotonsillectomy
operations fitted a 3-modal distribution in female subjects and a 2-modal
distribution in male subjects (Figure 2).
The multimodal distribution of the age-specific frequencies of tonsillectomies
suggested that the subjects could be grouped in 3 age groups corresponding
to each of the 3 peaks of the multimodal distribution (<10 years, 10-19
years, 20-29 years). The proportions of female and male subjects undergoing
operations in each of these age groups were then analyzed. Adenoidectomies
were performed more frequently on male than on female subjects among children
younger than 10 years (Table 1).
Tonsillectomies and adenotonsillectomies were performed more frequently on
female than male subjects among individuals aged between 10 and 20 years (Table 1).
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Table 1. Number of Adenoidectomy, Adenotonsillectomy (Tonsillectomy
With Concurrent Adenoidectomy), and Tonsillectomy (Without Concurrent Adenoidectomy)
Operations at HUCH During 1997 and 1998 by Age*
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The multimodal distribution of the age-specific frequencies of operations
suggested that the age of the patient might be associated with a distinct
cause of tonsillar disease. To facilitate the analysis, the indications for
tonsillectomy and adenotonsillectomy were grouped in 3 categories. The first
group of subjects had tonsillar or adenotonsillar hyperplasia (ICD-10 codes J35.1 and J35.3). This group of subjects included patients
who were operated on because of obstructive symptoms such as mouth breathing
and snoring but also patients with recurrent sinusitis or otitis media. The
second group of subjects included patients who were operated on because of
a severe acute tonsillar infection such as peritonsillar abscess (ICD-10 code J36), retropharyngeal abscess (ICD-10 code J39), neck lymphadenitis (ICD-10 code
L04), acute tonsillitis (ICD-10 code J03.9), or mononucleosis
(ICD-10 code B27). The third group of subjects had
chronic tonsillitis (ICD-10 code J35.0) who suffered
from recurrent episodes of tonsillitis and sore throat.
The indications for tonsillectomies (without concurrent adenoidectomy)
were reviewed in each of the 3 age groups. The group of patients operated
on because of abscesses and acute infections was the largest. The proportion
of these patients was the highest in individuals aged 10 to 19 years (Table 2). The proportion of patients having
tonsillar hyperplasia (ICD-10 code J35.1) decreased
and the proportion of patients having chronic tonsillitis (ICD-10 code J35.0) increased with increasing age (Table 2). The indications for adenotonsillectomies (tonsillectomy
with concurrent adenoidectomy) in each group resembled the indications of
tonsillectomies, the proportion of patients having tonsillar or adenotonsillar
hyperplasia (ICD-10 codes J35.1 or J35.3) decreased
and the proportion of patients having chronic tonsillitis (ICD-10 code J35.0) increased with increasing age (Table 3).
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Table 2. Number of Tonsillectomies (Without Concurrent Adenoidectomy)
Performed on Patients With Tonsillar Hyperplasia, Abcesses and Acute Infections
and Chronic Tonsillitis at HUCH During 1997 and 1998*
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Table 3. Number of Adenotonsillectomies (Tonsillectomy With Concurrent
Adenoidectomy) Performed on Patients With Tonsillar Hyperplasia, Abscesses,
and Acute Infections and Chronic Tonsillitis at HUCH During 1997 and 1998*
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When the age-specific proportions of females and males in each of the
diagnosis group were analyzed, the results showed that female subjects were
operated on for chronic tonsillitis more frequently than males in age groups
10 to 19 years (z = 2.17, P
= .03) and 20 to 29 years (z = 2.858, P = .004, Table 4). Although
tonsillectomies were apparently performed with similar frequencies on both
female and male subjects aged 20 to 29 years (Table 2), females were operated on in this age group more frequently
for chronic tonsillitis than for other reasons (2 = 12.37, P<.01, Table 4).
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Table 4. The Number of Tonsillectomies (Without Concurrent Adenoidectomy)
Performed on Patients With Tonsillar Hyperplasia, Abscesses, and Acute Infections
and Chronic Tonsillitis at HUCH During 1997 and 1998*
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The distributions of the indications for tonsillectomies and adenotonsillectomies
in each age group could only partly explain the multimodal distribution of
the age-specific frequencies of tonsillectomies. The frequency of tonsillectomies
performed because of peritonsillar abscesses and other acute infections still
depicted an apparent multimodal distribution (Figure 3).
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Figure 3. Numbers of tonsillectomy and adenotonsillectomy
operations at Helsinki University Central Hospital during 1997 and 1998 as
grouped by the indication for surgery. Each bar shows the number of operations
performed on patients at a given age. The numbers of tonsillectomy and adenotonsillectomy
operations performed because of hyperplasia are plotted in Figure 3A-D, respectively.
The number of operations performed because of abscesses and other acute infections
are plotted in Figure 3B-E, and the numbers of operations performed because
of chronic tonsillitis are plotted in Figure 3C-F. In each figure part the
curve for the best fitting mixture of normal distributions is superimposed.
Mixtures of normal distributions were fitted in sequence of 1, 2, and 3 normal
distributions. A combination of 3 normal distributions adequately fitted the
observed age distribution of patients who had tonsillectomy because of abscesses
and other acute infections likelihood ratio test: Figure 3B, 23= 39.2, P<.01. A combination of 2 normal distributions
adequately fitted the observed age distribution of the other patient groups
(likelihood ratio test: Figure 3A, 23= 64.0, P<.01; Figure 3C, 23= 26.0, P<.01;
Figure 3D, 23= 107.8, P<.01; Figure
3E, 23= 17.1, P<.01; and Figure
3F, 23= 30.8, P<.01).
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The major indications for adenoidectomy were otitis media, sinusitis,
or obstructive symptoms related to adenoidal hyperplasia. Of the individuals
returning the questionnaire, 109 gave information on the indication of adenoidectomy.
Of these 83 (76%) had underlying otitis media or sinusitis. Otitis media was
the indication for adenoidectomy, particularly in children younger than 4
years, for whom 79.2% otitis media was reported as the indication. The proportion
of children undergoing adenoidectomy because of otitis media decreased with
increasing age. In children aged 8 years or older this proportion was only
28.6% (2 = 16.09, P<.001, Table 5). A decreasing proportion of otitis
media but an increasing proportion of sinusitis as the indication for adenoidectomy
was also seen in patients operated on at HUCH.
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Table 5. Indications for Adenoidectomy in 109 Survey Respondents Who
Gave Information on the Indication of Adenoidectomy and in 989 Adenoidectomy
Operations Performed at HUCH during 1997 and 1998*
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The effect of the number of siblings, family income, site of residence,
year of birth, and type of day care for children aged younger than 3 years
on the frequency of adenoidectomy, tympanostomy, and tonsillectomy operations
is given in Table 6. The frequency
of tonsillectomies was low in children of families with a low annual family
income (<15 200 Euros; P = .04, Fisher exact
test). The frequency of the operations appeared to be higher in children who
had attained day care at municipal day-care centers during the first 3 years
of life. The number of children whose day-care status was known was, however,
small and the observed difference did not reach statistical significance.
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Table 6. Frequency of Adenoidectomy, Tympanostomy, and Tonsillectomy
Operations Among Individuals Who Responded to the Questionnaire*
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COMMENT
The frequencies of tonsillectomy operations at different ages followed
a multimodal distribution, the first peak occurring around the age of 5 to
6 years, and the second around 14 to 16 years. Further, a third peak after
the age of 20 years was observed in the age-specific frequencies of tonsillectomies
performed on female subjects. In previous reports the frequencies of tonsillectomies
have been reported on all individuals younger than 5 years, on all individuals
aged from 5 to 9 years, and on all individuals aged from 10 to 14 years,3, 4, 5 resulting in a possible
failure to detect a relative decrease in the frequency of tonsillectomy operations
performed on children aged between 9 to 11 years.
The cause of tonsillar disease was associated with the age of the patient
in that tonsillar hyperplasia was the most frequent cause in children younger
than 10 years, in teenagers the cause of tonsillar disease was most frequently
related to abscesses and acute infections, whereas chronic tonsillitis was
the most frequent in individuals older than 20 years. The temporal pattern
of the cause of tonsillar disease starting from hyperplasia or abscesses and
ending in chronic tonsillitis may represent a continuum of different manifestations
of a single entity of a tonsillar disease. It may be that bacterial growth
within a hyperplastic tonsil leads to the formation of abscesses in teenagers.
Later on it is possible that previous formations of scar tissue prevent the
development of large abscesses but the disease manifests as chronic tonsillitis.
However, it is possible that small, clinically undetected abscesses may later
lead to chronic tonsillitis.
An association of adult chronic tonsillitis and peritonsillar abscesses
is also evident in that anaerobic bacteria have been implicated as pathogens
in both diseases. Anaerobic bacteria such as Fusobacterium
necrophorum, Fusobacterium nucleatum, Prevotella melaninogenica, Prevotella
intermedia, Peptostreptococcus micros, and Actinomyces odontolyticus are frequently recovered from
peritonsillar abscesses.6 Fusobacterium, pigmented Prevotella, Porphyromonas, and Peptostreptococcus species can also be recovered in the tonsils of patients with chronic
tonsillitis.7, 8 In addition, patients
with chronic tonsillitis have increased levels of antibodies against F nucleatum and P intermedia suggesting
that these bacteria have a role in chronic tonsillitis.9
Although adenoidectomies performed on children younger than 10 years
were more frequent among boys than girls, the frequencies of tonsillectomies
and adenotonsillectomies were higher among female than male subjects aged
between 10 and 19 years. The results are consistent with previous reports
indicating that adenoidectomies are more frequent among boys than girls younger
than 4 years,3, 4, 5
and that the frequency of tonsillectomies among teenagers is higher in female
than in male subjects.3, 4, 5
The unequal sex distribution in the cause of tonsillar disease suggests that
tonsillar disease is slightly different in the female than in the male patient.
The frequencies of adenoidectomy, tympanostomy, and tonsillectomy operations
have usually been estimated by comparing hospital discharge records with the
total child population.3, 5, 10, 11, 12, 13
For example, the frequency of adenotonsillectomy operations per 100 000
individuals younger than 15 years has been estimated to range from 303 to
787 in the United States.12 Although accurate
comparisons between the cumulative frequencies of operations obtained from
questionnaires and the frequencies of operations obtained from hospital discharge
records cannot be made, it appears that the cumulative frequency of adenoidectomy
operations is high in Finland.
Previous studies have shown large geographical variation in the frequencies
of tonsillectomies.5, 10, 11, 13, 14, 15, 16, 17, 18
Also temporal variations in the frequencies of adenoidectomies and tonsillectomies
occur.3, 5, 12, 19, 20
The variations in the operation frequencies may reflect variations in the
indications for the operations, in the availability of medical services, and
in the incidence of upper respiratory tract infections.
The cumulative frequencies of adenoidectomy and tympanostomy operations
in this article were close to those reported in a previous questionnaire study
involving 1708 Finnish children in 119 randomly selected second grade classes.21 In our study the cumulative frequency of adenoidectomy
among 9-year-old children was approximately 20% and that of tympanostomy 8%.
The cumulative frequency of adenoidectomy operations in the previous study
was 17% and that of tympanostomy operations 8.6% in a child population with
a mean age of 8.7 years.21
Low family income was associated with a decreased rate of tonsillectomy
operations but not with the rate of adenoidectomy or tympanostomy operations.
A significant proportion of tonsillectomies were performed on children older
than 10 years. It is, therefore, possible that older children from families
with a low family income may not reach medical services as easily as other
children. However, in this income class mothers are frequently not contributing
to the family income and stay at home, which may, in turn, be associated with
a decreased risk for tonsillar disease in children of these mothers.
The frequency of operations among children younger than 3 years who
had day care at a municipal day-care center seemed to be higher than among
those children who did not have day care at day-care centers. However, the
number of children of which the type of day care was known was small and the
difference in the rate of the operations in our study did not reach statistical
significance. Day care at day care-centers has previously been associated
with an increased frequency of adenoidectomy and tympanostomy tube operations
in Finland.22 In another study day-care at
day care centers was associated with an increased cumulative incidence of
tympanostomy tube insertions (31%, 108/346) as compared with children who
were taken care of at home (11%, 7/63).23 Increased
frequency of operations performed on children receiving out-of-home day care
may reflect increased exposure to pathogenic microbes at day-care centers.
The most frequent indication for adenoidectomy in children younger than
4 years was otitis media. In older children sinusitis was more prevalent.
The development of nasal sinuses and the growth of the eustachian tube with
increasing age of the child may result in the development of purulent infections
into the nasal sinuses rather than into the middle ear cavity.
CONCLUSIONS
The grouping of individuals in 3 age groups according to sex and distinct
distributions of the indications for the operations only partly explained
the multimodal nature of the age-specific frequencies of tonsillectomy. The
age-specific frequencies of tonsillectomies performed because of peritonsillar
abscesses still followed a multimodal distribution. The observed multimodality
may reflect potential differences in the causative factors leading to tonsillar
disease in the 3 age groups. These factors may be environmental such as exposure
to the causative agent of mononucleosis that in our material led to tonsillar
pathology preferentially in teenagers. However, these factors may be intrinsic
to normal development such as to endocrine phenomena associated with puberty
that may contribute to tonsillar disease in teenagers and that may result
to female preponderance among teenagers undergoing tonsillectomy.
AUTHOR INFORMATION
Accepted for publication June 28, 2000.
This study received financial support from the Paulo Foundation, Helsinki,
Finland.
From the Departments of Otorhinolaryngology (Drs Mattila and Tahkokallio)
and Pathology (Dr Tarkkanen), Helsinki University Central Hospital, Helsinki,
Finland; and the National Public Health Institute, Diabetes and Genetic Epidemiology
Unit, Mannerheimintie, Finland (Mr Pitkäniemi and Drs Karvonen and Tuomilehto).
Corresponding author and reprints: Petri S. Mattila, MD, Department
of Otorhinolaryngology, Helsinki University Central Hospital, Haartmaninkatu
4 E, FIN-00290 Helsinki, Finland (e-mail: petri.mattila{at}huch.fi).
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Respiratory infections in schoolchildren: co-morbidity and risk factors
Karevold et al.
Arch. Dis. Child. 2006;91:391-395.
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