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ORIGINAL CONTRIBUTION
Prevalence of Carpal Tunnel Syndrome
in a General Population
Isam Atroshi, MD
Christina Gummesson, MS
Ragnar Johnsson, MD, PhD
Ewald Ornstein, MD
Jonas Ranstam, PhD
Ingmar Rose´n, MD, PhD
C
ARPAL TUNNEL SYNDROME
(CTS), or compression neu-
ropathy of the median nerve
at the wrist, is a cause of pain,
numbness, and tingling in the upper ex-
tremities
1,2
and an increasingly recog-
nized cause of work disability.
3,4
Carpal
tunnel syndrome constitutes a major part
of the occupational upper-extremity dis-
orders and is associated with consider-
able health care and indemnity costs.
4
Although CTS has been described as
the most common peripheral mononeu-
ropathy,
2
little is known about its preva-
lence in the general population. We have
found only 1 prospective population-
based study, performed in the Nether-
lands in 1985, that attempted to deter-
mine the prevalence of CTS.
5
In a survey
of 715 subjects (33% men) aged 25 to
74 years, the prevalence of electrophysi-
ologically confirmed CTS was 5.8% in
women and 0.6% in men.
5
However, the
study’s sample size and response rate
were probably inadequate, reducing its
precision.
Higher prevalence rates for CTS have
been found in certain occupational
groups.
6-8
However, in the absence of
an accurate estimate of the prevalence
in the general population, it is diffi-
cult to interpret prevalence rates re-
lated to specific occupations. There-
fore, we conducted an epidemiologic
study to estimate the prevalence of CTS
in a general population.
METHODS
Study Population and Survey
A sex- and age-stratified sample of 3000
subjects, aged 25 to 74 years, was ran-
domly selected from the population reg-
ister of northeastern Scania in southern
Sweden. This region has a population of
170 000 inhabitants,whose demographic
characteristics are similar to those of the
Swedish general population.
9
The study
was approved by the Ethics Committee
at Lund University’s Medical Faculty.
Author Affiliations: Department of Orthopedics, Ha¨ ssle-
holm-Kristianstad Hospital, Kristianstad, Sweden (Drs
Atroshi and Ornstein); Lund University, Lund, Sweden
(Ms Gummesson); Departments of Orthopedics (Dr
Johnsson) and Clinical Neuroscience, Division of Clini-
cal Neurophysiology (Dr Rose´ n), Lund University Hos-
pital, Lund; and Department of Health and Society,
Malmo¨ University, Malmo¨ , Sweden (Dr Ranstam).
Corresponding Author and Reprints: Isam Atroshi,
MD, Department of Orthopedics, Ha¨ ssleholm-
Kristianstad Hospital, S-291 85 Kristianstad, Sweden
(e-mail: isam.atroshi@mailbox.swipnet.se).
Context Carpal tunnel syndrome (CTS) is a cause of pain, numbness, and tingling in
the hands and is an important cause of work disability. Although high prevalence rates
of CTS in certain occupations have been reported, little is known about its prevalence
in the general population.
Objective To estimate the prevalence of CTS in a general population.
Design General health mail survey sent in February 1997, inquiring about symp-
toms of pain, numbness, and tingling in any part of the body, followed 2 months later
by clinical examination and nerve conduction testing of responders reporting symp-
toms in the median nerve distribution in the hands, as well as of a sample of those not
reporting these symptoms (controls).
Setting A region in southern Sweden with a population of 170 000.
Participants A sex- and age-stratified sample of 3000 subjects (age range, 25-74
years) was randomly selected from the general population register and sent the sur-
vey, with a response rate of 83% (n = 2466; 46% men). Of the symptomatic respond-
ers, 81% underwent clinical examination.
Main Outcome Measures Population prevalence rates, calculated as the number of
symptomatic responders diagnosed on examination as having clinically certain CTS and/or
electrophysiological median neuropathy divided by the total number of responders.
Results Of the 2466 responders, 354 reported pain, numbness, and/or tingling in
the median nerve distribution in the hands (prevalence, 14.4%; 95% confidence in-
terval [CI], 13.0%-15.8%). On clinical examination, 94 symptomatic subjects were
diagnosed as having clinically certain CTS (prevalence, 3.8%; 95% CI, 3.1%-4.6%).
Nerve conduction testing showed median neuropathy at the carpal tunnel in 120 symp-
tomatic subjects (prevalence, 4.9%; 95% CI, 4.1%-5.8%). Sixty-six symptomatic sub-
jects had clinically and electrophysiologically confirmed CTS (prevalence, 2.7%; 95%
CI, 2.1%-3.4%). Of 125 control subjects clinically examined, electrophysiological me-
dian neuropathy was found in 23 (18.4%; 95% CI, 12.0%-26.3%).
Conclusion Symptoms of pain, numbness, and tingling in the hands are common in
the general population. Based on our data, 1 in 5 symptomatic subjects would be ex-
pected to have CTS based on clinical examination and electrophysiologic testing.
JAMA. 1999;282:153-158 www.jama.com
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A questionnaire was devised that in-
corporated questions from a validated
general health survey,
10
with questions
about medical history and the pres-
ence of pain, numbness, or tingling in
any part of the body during the preced-
ing 4 weeks as well as their localiza-
tion, duration, frequency, and severity.
Whole body diagrams were provided for
marking pain, numbness, and tingling.
Demographic data included sex, age,
handedness, height, weight, social sta-
tus, education, amount of exercise,
smoking habits, employment, and work
activities. The study was presented in the
local media 1 week before the mailing
of the questionnaires. To reduce selec-
tion bias, the study was described as a
general health survey. The question-
naires were mailed to the 3000 sub-
jects in February 1997. Two consecu-
tive reminders were mailed to those who
did not respond within 3 weeks. All re-
turned questionnaires were reviewed
twice by 2 investigators to identify sub-
jects reporting symptoms in the me-
dian nerve distribution in the hands. Re-
sponders who reported pain, numbness,
and/or tingling in 2 or more of the first
4 fingers at least twice weekly during the
preceding 4 weeks were identified. They
were then contacted by telephone or, if
necessary, by mail, and asked to come
to the hospital for a clinical examina-
tion and nerve conduction testing.
Controls were randomly selected
from the responders who reported no
hand symptoms, diabetes, rheumatic
disease, thyroid disorder, previous wrist
fracture, or carpal tunnel surgery. The
controls were also asked to come to the
hospital for examination.
Subjects in a random sample of 10%
of the nonresponders were contacted
by telephone and questioned about the
presence of hand symptoms.
Clinical Examination
The clinical examinations were begun 2
months after the initial mailing of the
questionnaires and conducted during a
4-week period. All subjects were exam-
ined by the same hand surgeon (I.A.),
who is experienced in the assessment of
CTS. Examination of both hands in-
cluded median nerve provocative tests
(Tinel nerve percussion and Phalen ma-
neuver), and evaluation of sensibility and
thenar muscle strength.
1,2
All hands pre-
viously operated on for CTS were ex-
cluded. Based on the history and the find-
ings at the clinical examination, the
examining physician diagnosed each
symptomatic subject as having either
clinically certain or clinically uncertain
CTS. The diagnosis of clinically certain
CTS required the presence of recurring
nocturnal and/or activity-related numb-
ness or tingling involving the palmar as-
pects of at least 2 of the first 4 fingers. It
usually included positive nerve percus-
sion and/or wrist flexion test results. The
presence of median nerve sensory and/or
motor deficit was supportive of the di-
agnosis, but was not considered nec-
essary. The diagnosis of clinically un-
certain CTS was considered for the
symptomatic subjects reporting poorly
defined median nerve paresthesias, whole
hand or arm paresthesias, or chronic pain
as the main clinical feature.
Nerve Conduction Testing
After the clinical examination the sub-
jects underwent nerve conduction test-
ing using an electromyography device
(Viking IV; Nicolet, Madison, Wis). The
nerve conduction testing was per-
formed by 3 experienced electromyog-
raphy technicians who were blinded to
the results of the preceding examina-
tion. Skin temperature was measured
prior to testing, and hands with a
temperature of less than 30°C were
warmed. Nerve conduction testing was
performed using the technique de-
scribed by Kimura
11
and included mea-
surements of median nerve distal sen-
sory latency (third finger–wrist) and
wrist-palm sensory conduction veloc-
ity, as well as ulnar nerve distal sen-
sory latency (fifth finger–wrist).
11,12
The results of the nerve conduction
testing were examined to identify sub-
jects with electrophysiological me-
dian neuropathy at the carpal tunnel.
The electrophysiological criterion used
for the diagnosis of median neuropa-
thy was median-ulnar sensory latency
difference,
13
with 0.8 milliseconds or
longer considered abnormal. This cut-
off was used in accordance with the pre-
viously reported normal values for me-
dian-ulnar wrist-digit latency difference
as measured with the technique de-
scribed by Kimura.
11
Data Analysis
We calculated the prevalence of pain,
numbness, and/or tingling in the me-
dian nerve distribution, clinically cer-
tain CTS, electrophysiological median
neuropathy, and clinically and electro-
physiologically confirmed CTS. The
prevalence rates were calculated as the
number of subjects in each of the 4 cat-
egories divided by the total number of
survey responders. Ninety-five per-
cent confidence intervals (CIs) were cal-
culated based on the Poisson distribu-
tion.
14
Sex- and age-specific prevalence
rates were also calculated. Sex-
specific overall prevalence rates were
age standardized using the general
Swedish population in December 1997
9
as an external standard. Group com-
parisons were performed using 2-tailed
x
2
tests for categorical data and t tests
for continuous variables, with signifi-
cance set at .05.
RESULTS
Survey
Of the 3000 subjects, 15 had recently
moved from the study region, 5 were
reported recently deceased, 8 were se-
verely ill or cognitively impaired, and
12 had recently relocated to unknown
addresses. Of the remaining 2960 sub-
jects, 2466 (83%) returned completed
questionnaires (F
IGURE).
Symptomatic Subjects
Symptoms of recurring pain, numb-
ness, and/or tingling in the median
nerve distribution were reported by 354
responders (34% men; mean [SD] age,
51 [13] years). There were 2112 non-
symptomatic responders (48% men;
mean [SD] age, 50 [15] years). A sig-
nificantly higher proportion of women
were symptomatic (P,.001).
Of the symptomatic responders, 287
subjects (81%) came to the hospital for
the clinical examination. Twenty-five
CARPAL TUNNEL SYNDROME
154 JAMA, July 14, 1999—Vol 281, No. 2 ©1999 American Medical Association. All rights reserved.
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subjects were excluded for the follow-
ing reasons: previous CTS surgery in the
symptomatic hand (n = 13), unwilling-
ness to undergo nerve conduction test-
ing (n = 2), and either resolution of the
median nerve symptoms or symptoms
not consistent with the inclusion cri-
teria (n = 10).
Clinical examination and nerve con-
duction testing were performed on 262
symptomatic subjects (35% men; mean
[SD] age, 52 [13] years). The results of
the clinical and electrophysiological ex-
aminations are shown in the Figure.
There was a fair-to-moderate agree-
ment between the clinical diagnosis
(clinically certain CTS vs clinically un-
certain or no CTS) and the electrophysi-
ological diagnosis (median neuropathy
or no median neuropathy) (k = 0.36;
P,.001), and good agreement be-
tween the clinical diagnosis alone and
the clinical and electrophysiological di-
agnosis (k = 0.75; P,.001).
14
Prevalence
The population prevalence of pain,
numbness, and/or tingling in the me-
dian nerve distribution was 14.4% (95%
CI, 13.0%-15.8%). The sex- and age-
specific prevalence rates are shown in
T
ABLE 1. The prevalence of clinically
certain CTS was 3.8% (95% CI, 3.1%-
4.6%). The prevalence of median nerve
symptoms and electrophysiological me-
dian neuropathy was 4.9% (95% CI,
4.1%-5.8%). The prevalence of clini-
cally and electrophysiologically con-
firmed CTS was 2.7% (95% CI, 2.1%-
3.4%). The sex- and age-specific
prevalence rates are shown in T
ABLE 2.
Medical and Occupational Data
Diabetes was reported in 3.0% of the
subjects with clinically and electro-
physiologically confirmed CTS and
3.2% of the remaining responders. Also
reported were thyroid disorder in 3.0%
and 3.0%, rheumatoid arthritis in 4.5%
and 1.9%, and overweight or obesity
(defined as body mass index of at least
25 kg/m
2
) in 70% and 47%, respec-
tively. The higher proportion of over-
weight or obese subjects in the CTS
population was significant (P,.001).
Clinically and electrophysiologically
confirmed CTS was present in 25 of 710
active blue-collar workers (prevalence,
3.5%), and in 12 of 712 active white-
collar workers (prevalence, 1.7%) (95%
CI for the difference, 0.2%-3.6%; P = .03).
The higher prevalence among active
blue-collar workers was significant even
after adjusting for sex, age, and body
mass index. The prevalence of con-
firmed CTS among working subjects
who reported more than 1 h/d use of ex-
cessive force with the hand during work
and those reporting less frequent or no
such use was 5.4% and 1.8%, respec-
tively (95% CI for the difference, 1.4%-
6.8%; P,.001). In a similar analysis of
other work-related activities (ie, use .1
Figure. Study Profile
Subjects Surveyed
(N
=
3000)
Deceased, Relocated, Severely Ill, Cognitively Impaired
(n
=
40)
Responders
(N
=
2466)
Symptomatic
(Pain, Numbness, Tingling in Median Nerve Distribution)
(n
=
354)
Clinical Examination
(n
=
287)
Median Neuropathy
(n
=
66)
No Neuropathy
(n
=
28)
Nerve Conduction Testing
Did Not Attend Clinical Examination
(n
=
67)
Clinically Certain
Carpal Tunnel Syndrome
(n
=
94)
No Neuropathy
(n
=
114)
Nerve Conduction Testing
Clinically Uncertain
Carpal Tunnel Syndrome
(n
=
168)
No Neuropathy
(n
=
102)
Excluded (n
=
25)
Previous Carpal Tunnel Surgery (n
=
13)
No Median Nerve Symptoms (n
=
10)
Declined Nerve Conduction Testing (n
=
2)
Excluded (n
=
9)
Neurologic Disease (n
=
1)
Median Nerve Symptoms (n
=
7)
Declined Nerve Conduction Testing (n
=
1)
Nerve Conduction Testing
Clinically No
Carpal Tunnel Syndrome
(n
=
125)
Median Neuropathy
(n
=
54)
Median Neuropathy
(n
=
23)
Clinical Examination
(Randomly Selected)
(n
=
134)
Nonresponders
(n
=
494)
Nonsymptomatic
(n
=
2112)
CARPAL TUNNEL SYNDROME
©1999 American Medical Association. All rights reserved. JAMA, July 14, 1999—Vol 281, No. 2 155
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h/d vs use #1 h/d), CTS prevalence in
the 2 groups was, for working with ex-
cessively flexed or extended wrist, 3.8%
and 1.7% (95% CI for the difference,
0.4%-4.1%; P = .01); for repetitive hand
or wrist motion, 2.4% and 2.7% (95% CI
for the difference, − 2.0%-1.5%; P = .69);
and for use of hand-held vibratory tools,
5.5% and 2.4% (95% CI for the differ-
ence, 0.0%-9.1%; P = .05).
Controls
Of the nonsymptomatic responders
asked to come to the hospital, 134 sub-
jects received a clinical examination.
Nine subjects were excluded for the fol-
lowing reasons: neurological disease
(n = 1), unwillingness to undergo nerve
conduction testing (n = 1), and pres-
ence of median nerve numbness or tin-
gling (n = 7).
Clinical examination and nerve con-
duction testing were performed on 125
control subjects (45% men; mean [SD]
age, 51 [14] years). In 3 subjects, nerve
conduction testing was performed on
only 1 hand owing to a previous nerve
laceration involving the right wrist
(n = 1) and unwillingness to proceed
with examination of the left hand (n = 2).
Electrophysiological median neu-
ropathy was found in 23 control sub-
jects (18.4%; 95% CI, 12.0%-26.3%)
(T
ABLE 3). Six of 41 active blue-collar
workers and 5 of 45 active white-
collar workers had median neuropa-
thy. Analysis of the work-related ac-
tivities in the controls did not show
significant differences regarding the
prevalence of median neuropathy.
Nonresponders
A total of 494 eligible subjects (52%
men; mean [SD] age, 47 [14] years) did
not respond to the questionnaire. The
nonresponders differed significantly
from the responders with respect to sex
(P = .02) and age (P,.001). Tele-
phone contact was attempted with 49
randomly selected nonresponders.
Twenty-two subjects could not be
reached, 1 was reported to have re-
cently died, and 2 declined to answer
any questions. Responses could thus be
obtained from 24 subjects (11 men).
Numbness and/or tingling in the hands
were reported in 6 subjects.
Sixty-seven symptomatic subjects
(37% men; mean [SD] age, 50 [12]
years) did not come to the clinical ex-
amination.
COMMENT
The findings of this epidemiologic study
of CTS, the largest to date, show this
compression neuropathy to be com-
mon in the general population. The
prevalence of upper-extremity pain and
paresthesias in the general population
has not been addressed in the litera-
ture. The high prevalence of these symp-
toms in the general population should
be borne in mind when assessing the pos-
sible relationship of upper-extremity
complaints to specific occupations.
Table 1. Prevalence of Pain, Numbness, and/or Tingling in the Median Nerve Distribution in Hands (N = 2466)
*
Age, y
Men
Women
Responders, No. Symptomatic, No.
Prevalence, %
(95% CI) Responders, No. Symptomatic, No.
Prevalence, %
(95% CI)
25-34 219 11 5.0 (2.5-8.8) 244 30 12.3 (8.4-17.1)
35-44 213 17 8.0 (4.7-12.5) 280 55 19.6 (15.1-24.8)
45-54 209 32 15.3 (10.7-20.9) 280 50 17.9 (13.5-22.8)
55-64 259 41 15.8 (11.6-20.8) 252 59 23.4 (18.3-29.1)
65-74 234 20 8.5 (5.3-12.9) 276 39 14.1 (10.2-18.8)
All† 1134 121 10.4 (8.6-12.2) 1332 233 17.3 (15.3-19.4)
*
CI indicates confidence interval.
†The sex-specific overall prevalence rates are age standardized to the Swedish general population.
Table 2. Sex- and Age-Specific Prevalence Rates of Carpal Tunnel Syndrome
*
Age, y
Men
Women
Clinically
Certain CTS
Electrophysiological
Median Neuropathy
at the Carpal Tunnel
Clinically and
Electrophysiologically
Confirmed Diagnosis
of CTS
Clinically
Certain CTS
Electrophysiological
Median Neuropathy
at the Carpal Tunnel
Clinically and
Electrophysiologically
Confirmed Diagnosis
of CTS
No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI)
25-34 3 1.4 (0.3-3.9) 4 1.8 (0.5-4.6) 2 0.9 (0.1-3.3) 7 2.9 (1.2-5.8) 5 2.0 (0.7-4.7) 4 1.6 (0.5-4.1)
35-44 3 1.4 (0.3-4.1) 6 2.8 (1.0-6.0) 2 0.9 (0.1-3.3) 16 5.7 (3.3-9.1) 11 3.9 (2.0-6.9) 8 2.9 (1.2-5.5)
45-54 11 5.3 (2.7-9.2) 17 8.1 (4.8-12.7) 9 4.3 (2.0-8.0) 11 3.9 (2.0-6.9) 18 6.4 (3.8-10.0) 8 2.9 (1.2-5.5)
55-64 10 3.9 (1.9-7.0) 14 5.4 (3.0-8.9) 8 3.1 (1.3-6.0) 14 5.6 (3.0-9.1) 20 7.9 (4.9-12.0) 8 3.2 (1.4-6.2)
65-74 4 1.7 (0.5-4.3) 7 3.0 (1.2-6.1) 3 1.3 (0.3-3.7) 15 5.4 (3.1-8.8) 18 6.5 (3.9-10.1) 14 5.1 (2.8-8.4)
All† 31 2.8 (1.8-3.8) 48 4.3 (3.1-5.5) 24 2.1 (1.3-3.0) 63 4.6 (3.5-5.7) 72 5.2 (4.0-6.3) 42 3.0 (2.1-3.9)
*
CTS indicates carpal tunnel syndrome; CI, confidence interval.
†The sex-specific overall prevalence rates are age standardized to the Swedish general population.
CARPAL TUNNEL SYNDROME
156 JAMA, July 14, 1999—Vol 281, No. 2 ©1999 American Medical Association. All rights reserved.
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Despite the high incidence of sur-
gery for CTS, no standard criteria for
clinical diagnosis have been estab-
lished.
1
There is also no consensus on
whether CTS is a clinical or electro-
physiological diagnosis. Normal elec-
trophysiological findings do not rule out
CTS.
15
In fact, most studies assessing the
sensitivity of nerve conduction testing
in diagnosing CTS have used the clini-
cal diagnosis as the criterion stan-
dard.
15
On the other hand, physical
examination for CTS also has been re-
ported to have limited sensitivity and
specificity.
16
Consequently, we calcu-
lated 2 separate prevalence rates: 1 in
which the diagnosis of CTS was made
on the basis of characteristic symp-
toms and signs and 1 requiring median
nerve symptoms combined with elec-
trophysiological median neuropathy. We
also calculated a conservative preva-
lence estimate based on clinically and
electrophysiologically confirmed diag-
noses. Although this figure may be an
underestimate because it excludes elec-
trophysiologically normal subjects with
clear clinical features of CTS, this preva-
lence estimate is important for epide-
miologic studies because it probably rep-
resents the highest level of classification
accuracy.
17
That only 1 clinician per-
formed the clinical examinations may be
a source of potential bias.
We found electrophysiological me-
dian neuropathy not only in 70% of the
subjects diagnosed as having clini-
cally certain CTS and in 46% of those
with paresthesias in the median nerve
distribution in the hands, but also in
18% of the nonsymptomatic control
subjects. Abnormal nerve conduction
testing results were more common
among older control subjects. The rea-
son for this high rate of asymptomatic
median neuropathy is unclear. Al-
though abnormal nerve conduction
testing results have been reported in
nonsymptomatic subjects, previous
electrodiagnostic studies generally have
not used controls randomly selected
from the general population.
15
Asymp-
tomatic median neuropathy has previ-
ously been found in 13% of 724 indus-
trial and/or clerical workers,
18
and in
16% of 1021 industrial job appli-
cants.
19
These 2 studies used median-
ulnar sensory latency difference mea-
sured at a distance of 14 cm (digit-
wrist) and 8 cm (palm-wrist),
respectively, using the 0.5-millisec-
ond cutoff commonly used for these
measurement techniques. A higher cut-
off for the latency difference has been
derived from the technique described
by Kimura, in which the median and
ulnar nerves are stimulated at a fixed
point (3 cm proximal to the wrist’s dis-
tal crease) and the recording made at
the interphalangeal joints of the third
and fifth digits, respectively.
11
A re-
cent study reporting normative me-
dian and ulnar nerve conduction val-
ues in 324 nonsymptomatic active
workers with a mean age of 36 years
suggested the use of a 0.8-millisecond
cutoff for the 14-cm sensory latency dif-
ference to reduce the false-positive
rate.
20
Our results using the alterna-
tive measurement technique also show
that the rate of asymptomatic median
neuropathy in a general population
appears to be higher than previously
reported in nonrandom, and often
smaller, control groups.
We found a strong association be-
tween overweight or obesity and the
presence of CTS. The other medical
conditions analyzed did not show sig-
nificant associations, although rheu-
matoid arthritis was more commonly
reported than the other conditions
among CTS subjects. Our findings of
higher CTS prevalence among blue-
collar than white-collar workers, and
among workers who reported using ex-
cessive force with the hand or work-
ing with excessive wrist flexion or ex-
tension, might provide additional
support to the role of work-related fac-
tors in CTS.
In our study, the prevalence of CTS
recorded in men (male-female ratio,
1:1.4) was higher than previously re-
ported.
5,21
This difference in the re-
ported prevalence rates might be due to
differences in the size and/or design of
earlier studies, or to a real increase in the
prevalence in men. Among older per-
sons, however, the prevalence in women
was almost 4 times that in men, with
older women showing the highest age-
specific prevalence for confirmed CTS.
Since we had a response rate exceed-
ing 80% for both the survey and the
clinical examination, we believe selec-
tion bias is a minor problem. Further-
more, the nonresponder analysis re-
vealed almost similar proportions of
symptomatic subjects among the non-
responders as among the responders.
In addition, the rate of false-positive
and false-negative questionnaire re-
sponses regarding hand symptoms
was shown to be low.
When calculating prevalence rates,
we assumed that symptomatic sub-
jects who did not come to the exami-
nation (19% of all symptomatic sub-
jects) did not have CTS. Consequently,
based on clinical and/or electrophysi-
ological criteria, the prevalence rates es-
timated in our study ought to be close
to, or somewhat lower than, the true
prevalence.
Estimation of CTSprevalence rates in
the general population may contribute
to earlydiagnosis and effective treatment
of symptomatic subjects and provideuse-
ful data for the interpretation of results
of studies that estimate CTS prevalence
in specific occupational groups.
Funding/Support: This study was supported by grants
from the Kristianstad County Council, the Medical
Faculty of Lund University, and by grants 17x-09509
and 14x-0084 from the Swedish Medical Research
Council.
Acknowledgment: We would like to thank electro-
myography technicians Marie Lindvall, Pernilla Lin-
de´n, and Inger Nordlund for their skillful neurogra-
phy work and Roger Nihle´ n, RN, for his useful technical
assistance.
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Table 3. Electrophysiological Median
Neuropathy Among a Random Sample of
125 Nonsymptomatic Survey Responders
Age, y
Median Neuropathy
No. (Male) %
25-34 2 (2) 8.7
35-44 2 (1) 7.8
45-54 5 (2) 18.5
55-64 4 (1) 23.5
65-74 10 (5) 31.2
All 23 (11) 18.4
CARPAL TUNNEL SYNDROME
©1999 American Medical Association. All rights reserved. JAMA, July 14, 1999—Vol 281, No. 2 157
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“When you come to a patient’s house, you should ask
him what sort of pains he has, what caused them, how
many days he has been ill, whether the bowels are
working and what sort of food he eats.” So says Hip-
pocrates in his work Affections. I may venture to add
one more question: what occupation does he follow?
—Bernardino Ramazzini (1633-1714)
CARPAL TUNNEL SYNDROME
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