Sally Adel Hakim
Prevalence and factors associated with carpal tunnel syndrome
35
Prevalence and factors associated with carpal tunnel syndrome among a
group of computer professionals
Sally Adel Hakim*
Lecturer at the department of Community, Environmental and Occupational medicine,
Faculty of Medicine, Ain Shams University
*
Abstract
Background: Carpal tunnel syndrome is a clinical condition resulting from an
occupational mechanical health hazard which could be prevented by proper ergonomics.
The aim of the study was to find out the prevalence of carpal tunnel syndrome
symptoms among the study group and to describe the association between carpal tunnel
syndrome and some risk factors.
Methods: A cross-sectional study including 300 computer professionals from different
private sectors were interviewed using a questionnaire, observation of the hand position
during work and undergoing Phalen's test for the participants were done.
Results: Prevalence of carpal tunnel syndrome was higher among females and among
those aged more than 30 years old. Longer years of work and daily working hours, hand
position as extended or flexed were factors significantly higher among those with carpal
tunnel syndrome. Current smoking, history of diabetes mellitus, hypertension, thyroid
disease and use of contraceptive pills were factors not significantly associated with carpal
tunnel syndrome.
Conclusion: Carpal tunnel syndrome is a condition prevalent among computer
professionals. Proper ergonomics may help decrease the risk of suffering from this
condition.
Keywords: Carpal tunnel syndrome, health hazards of computer professionals
Introduction
Carpal tunnel syndrome is an entrapment
median neuropathy, causing paresthesia,
pain, numbness. The patho-physiology is
considered to be compression of the
median nerve travelling through the
carpal tunnel (1). Trauma caused by
The Egyptian Journal of Community Medicine
repetitive hand motion has been
identified as an aggravating factor for
carpal tunnel syndrome especially in
persons whose work requires repeated
forceful finger and wrist flexion and
extension. The incidence of carpal tunnel
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Prevalence and factors associated with carpal tunnel syndrome
syndrome has been reported to be high
among those working with vibrating
machinery and among office workers
especially typists and data entry clerks
(2).
From the studies that were done in that
field, one study revealed that (614) out
(982) supermarket checkers surveyed
reported symptoms for carpal tunnel
syndrome.
In
one
electronic
manufacturing
plant
with
(700)
employees, a review of workers
compensation claims revealed a total of
(52) cases of carpal tunnel syndrome
over a 5 year period. Out of a group of
(788) meat handlers, (117) had surgical
treatment for carpal tunnel syndrome
over a 12 year period. A survey of (400)
Americans surgeons reported that each
surgeon performed an average of (65)
operations for carpal tunnel syndrome
per year. Carpal tunnel syndrome is
more common in females. The estimated
lifetime risk of developing this
syndrome is about (10%) of adults (3).
According to an (2007) report from the
Bureau of Labor (4) Statistics, carpal
tunnel syndrome was associated with the
second longest average time away from
work (28 days) among the major
disabling diseases and illnesses in all
private industries.
In one study, nearly half of all patients
with carpal tunnel syndrome changed
jobs within 30 months of an initial
diagnosis (5). Another work (6) provided
information that high quality information
on occupation association of carpal
tunnel syndrome. High prevalence was
observed in manufacturing (42%),
construction (66%), personal services
industries (66%) and in trade and
commerce sectors (49%).
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A number of etiological factors have
been suggested to be potentially
etiologic for carpal tunnel syndrome.
These include repetitive prolonged hand
intensive activities, forceful exertions,
awkward or static posture, vibration,
temperature extremes and localized
mechanical stress (7).
The incidence of carpal tunnel syndrome
has been reported to be high among
those working with vibrating machinery
and among office workers especially
typists and data entry clerks (8).
A study done among female video
display terminal operators who were
engaged in data entry for about 6 hours a
day, has reported a high prevalence of
subclinical carpal tunnel syndrome (9).
In a survey of employees who were
identified as frequent computer users,
29.6% reported hand paresthesia and
10.5% met clinical criteria for carpal
tunnel syndrome (10).
The diagnosis of carpal tunnel syndrome
is based mainly on clinical and
electrophysiological
examination.
Clinical signs consist of pain, paresthesia
(numbness and tingling) and hyposthesia
of the three and half radial digits, as well
as a decrease in grip strength and hand
clumsiness. These complaints get worse
at night and upon exertion. Provocative
tests, such as the most commonly used
wrist flexion test (Phalen test) and
percussion test (Hoffman-Tinel sign) are
also widely used. Both tests consist of an
evocation or intensification of the
symptoms by maintaining the wrist in
flexion (Phalen position) and percussion
over the transverse carpal ligament, thus
causing
paresthesias
along
the
distribution of the median nerve (11).
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Prevalence and factors associated with carpal tunnel syndrome
From the above mentioned points, it is
clear how carpal tunnel syndrome is a
clinical condition which is common and
at the same time can be prevented to
avoid the high rates of absenteeism and
lost work hours as a consequence of this
medical condition.
Subjects and methods
A cross-sectional study was carried out.
All subjects from different private sector
locations including those working in
theses editing, data entry and system
administrators were included such that
they have been working in that field for
at least 6 months until calculated sample
size was reached.
A questionnaire was used in this work
including: socio-demographic details,
information about years of computer
work, hours of computer work per day,
computer job function, smoking habit,
use of alcohol, co-morbid conditions as
arthritis, diabetes, gout, hypothyroidism,
pregnancy, obesity, menopause, use of
oral contraceptives.
The participants were asked to
demonstrate how they normally keep
their hands while working with
computers. By carefully observing this,
it will be recorded in the questionnaire if
the hand was normally kept in a flexed,
extended or neutral position. A neutral
position refers to the lower arm and hand
kept in a straight line position without
flexion and extension at the wrist and
without radial or ulnar deviation.
Participants were asked whether they
had pain or numbness on the anterior
surface of the index, middle or radial
half of the ring finger for the past week
as a clinical symptom of carpal tunnel
syndrome.
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A person who has this clinical symptom
and is positive for Phalen's sign was
diagnosed as having carpal tunnel
syndrome.
Phalen test was elicited by asking the
subjects to rest their elbows on a table
with the forearms perpendicular to the
surface and to flex the wrists down and
away from the body for a period of 60
seconds. Phalen sign was considered
positive if paresthesia was elicited in the
median nerve distribution (12).
Sample size: It was calculated by epi
info program, population survey with
prevalence of the condition under study
among computer professionals as 13.1%
(14) ± 5%, under confidence level 99%
as equal 300 subjects.
Ethical consideration: Anonymous
questionnaire. An oral consent will be
obtained
from
participants
after
explaining the objectives of the study
and the interpretation of the used tests.
Results:
Table (1) shows that most of participants
were females.
Table (2) shows that the prevalence of
carpal tunnel syndrome was higher
among females than among males yet
with
no
statistically
significant
difference and was significantly higher
among those aged more than 30 years
than among those aged ≤ 30 years old.
Table (3) shows that among those with
carpal tunnel syndrome, the percentage
of those working from 4-8 years is
significantly higher than the percentage
of those working less than 4 years, also
the percentage of those working from 812 hours daily is significantly higher
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Prevalence and factors associated with carpal tunnel syndrome
than that of those working less than 8
hours daily and the percentage of those
who were observed having their hands in
flexed or extended positions while
working is significantly higher than the
percentage of those working with their
hands in neutral position. Moreover, the
highest percentage of those with carpal
tunnel syndrome was among data entry
workers (50%|) followed by those
working in editing (43.6%).
Table (4): This table shows that there
was no significant association between
history of diabetes, hypertension, thyroid
disease, use of contraceptive pills,
current smoking and diagnosis of carpal
tunnel syndrome.
Table (5): This table shows that there is
no significant association between
reporting neck pain and having carpal
tunnel syndrome, while the percentage
of those with carpal tunnel syndrome
reporting shoulder arm pain was
significantly higher than the percentage
of those with carpal tunnel syndrome
who did not report this complaint. Also,
it was found that all who complained of
arm edema had carpal tunnel syndrome.
Discussion
The current study showed that the
prevalence of carpal tunnel syndrome
was higher among females than among
males. This finding agrees with the
prevalence of carpal tunnel syndrome in
the general population which is found to
be higher among females than males
(13). Moreover, it was found that
prevalence of carpal tunnel syndrome
was higher in older age groups (table 2).
These findings agree with those of a case
control study on CTS where female
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38
gender and ages of (41-60) years were
significantly more frequent in the case
group (14). CTS was also significantly
associated female gender in a study
among Kuwaitian office workers (23).
The finding that carpal tunnel syndrome
is associated with longer years of work
and longer working hours agrees with
the results of another study where longer
years of exposure as a computer
professional and longer hours of work /
day have been found to be risk factors
for carpal tunnel syndrome (15).
In another study done among 25000
workers using video display terminals
who were involved in data entry and
mental arithmetic tasks, a physical
symptoms score became higher with
increasing duration of daily video
display terminal use (16).
Another work found that increasing
work duration increased the probability
of carpal tunnel syndrome risk among
video display terminal operators (17).
Longer work years was also a significant
risk factor associated with carpal tunnel
syndrome in an Egyptian assembly
factory (18)
The finding that the percentage of those
with carpal tunnel syndrome and
working with their hands in flexed or
extended is significantly higher than the
percentage of those working with their
hands in neutral position conforms to the
biological plausibility since the carpal
tunnel becomes narrower when the hand
is kept flexed or extended at the wrist
joint compared to a neutral position (19).
In another work, it was found that
computer workers who kept their wrists
extended by more than 20 degrees were
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Prevalence and factors associated with carpal tunnel syndrome
at greater risk of developing carpal
tunnel syndrome (20).
This requires attention to ergonomics.
Keeping the hand in a neutral position
while working with a computer can be
facilitated to a great extent by having a
fully adjustable chair and a proper
positioning of the keyboard and mouse.
Creating awareness among computer
professionals regarding keeping the hand
in a neutral position is also important.
In the current study, it was found that
there was no association between history
of hypertension, diabetes mellitus,
thyroid disease, use of contraceptive
pills, current smoking and diagnosis of
carpal tunnel syndrome, while in another
work diabetes and thyroid disease
history were associated with carpal
tunnel syndrome while smoking and the
use of contraceptive pills were not
associated with CTS (21). On the other
hand, diabetes mellitus and cigarette
smoking were identified as risk factors
for carpal tunnel syndrome (22). Sudha
etal., 2012 found that carpal tunnel
syndrome was significantly associated
with the number of comorbid conditions
among a group of office workers (23).
Shoulder arm pain was significantly
reported by carpal tunnel syndrome
diagnosed participants (table 5), in
another study significant predictors for
carpal tunnel syndrome included history
of numbness, tingling, burning and/or
pain in the hand (24).
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41
Table (1): Distribution of the study group by age and gender:
Age
Males
Females
Total
No. (%)
No. (%)
No. (%)
≤ 30 years
26 (30.2)
60 (69.8)
86 (100)
˃ 30 years
75 (35)
139 (65)
214 (100)
total
101 (33.7)
199 (66.3)
300 (100)
Table (2): Prevalence of carpal tunnel syndrome as per gender and age:
Prevalence
95% CI
P- value
0.82
˃ 0.05
No. (%)
Gender
Males
33 (32.7)
Females
79 (39.7)
– 2.24
Age
≤ 30 years
15 (17.4)
˃ 30 years
97 (45.3)
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Table (3): Association between computer work characteristics and carpal
tunnel syndrome:
Carpal tunnel syndrome
no
yes
< 4 years
36 (19.1)
7 (6.2)
4 – 8 years
116 (61.8)
86 (76.8)
36 (19.1)
19 (17)
188 (100)
112 (100)
˂8
26 (13.8)
28 (25)
8 – 12
125 (66.5)
69 (61.6)
˃ 12
37 (19.7)
15 (13.4)
Total
188 (100)
112 (100)
Data entry
94 (50)
57 (50.9)
Editing
82 (43.6)
46 (41.1)
System administrator
12 (6.4)
9 (8)
total
188 (100)
112 (100)
Neutral
84 (44.7)
26 (23.2)
Flexed or extended
104 (55.3)
86 (76.8)
Chi square
P value
10.702
< 0.05
6.725
˂ 0.05
0.392
˃ 0.05
13.92
˂ 0.05
Years of computer work
˃ 8 years
total
Hours of computer work / day
Job nature
Hand position
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Prevalence and factors associated with carpal tunnel syndrome
43
Table (4): Association between current smoking and some medical
conditions with carpal tunnel syndrome:
Carpal tunnel syndrome
no
yes
No
127 (67.6)
79 (70.5)
yes
61 (32.4)
33 (29.5)
No
165 (87.8)
104 (92.9)
yes
23 (12.2)
8 (7.1)
No
170 (90.4)
104 (92.9)
yes
18 (9.6)
8 (7.1)
No
171 (91)
100 (89.3)
Yes
17 (9)
12 (10.7)
No
173 (92)
102 (91.1)
Yes
15 (8)
10 (8.9)
No
173 (92)
106 (94.7)
yes
15 (8)
6 (5.3)
Chi square
P - value
0.3
˃ 0.05
1.963
˃ 0.05
0.524
˃ 0.05
0.225
˃ 0.05
0.083
˃ 0.05
0.79
˃ 0.05
Current smoking
Hypertension
Diabetes mellitus
Arthritis
Thyroid
Use of contraceptive pills
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Prevalence and factors associated with carpal tunnel syndrome
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Table (5): Relationship between some symptoms as reported by
participants and carpal tunnel syndrome:
Carpal tunnel syndrome
No
yes
No
121 (64.4)
77 (68.8)
Yes
67 (35.6)
35 (31.2)
No
144 (76.6)
46 (41.1)
Yes
44 (23.4)
66 (58.9)
No
188 (100)
90 (80.4)
yes
0 (0)
22 (19.6)
Chi
square
P value
0.438
˃ 0.05
38.1
˂ 0.05
39.8
˂ 0.05
Neck pain
Shoulder arm pain
Arm edema
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