Summary

Objective: To assess the prevalence of musculoskeletal disorders, visual strain and psychological stress in doctors who frequently use display screen equipment (DSE); to investigate the components of DSE which may contribute to these conditions, and to study the impact of symptoms on their work performance.

Design: Descriptive, cross-sectional questionnaire survey.

Subjects: Sixty-two doctors in the New Territories West Cluster, Family Medicine Department, were recruited into the study.

Main outcome measures: Data on musculoskeletal disorders, visual strain and psychological stress, collected from doctors who frequently used DSE, using standardized display screen equipment (DSE) and computer workstation users (Doctor) questionnaire developed from the Nordic Questionnaire.

Results: The overall response rate was 77.4%. The prevalence of complaints in various body parts for primary care doctors who frequently used DSE in the past 12 months were: neck 70.8%, shoulder 50%, wrist/hand symptoms 45.8%, upper back 45.8%, lower back 52.1%, sore eye 68.8%.

68.8% reported problems in DSE usage. The mouse usage showed OR 17.43 (95% CI 1.77-292.4, p value 0.042) for wrist and hand symptoms after adjusting for confounders in a logistic regression model.

75% indicated that joint problems or psychological stress caused extra stress at work, which affected their work efficiency and performance.

Conclusion: The prevalence of complaints in various body parts for primary care doctors who frequently used DSE in the past 12 months was high. They should be trained in basic skills of body use including work techniques, relaxation and rhythm, and the correct use of computer equipment. They should also be familiar with different types of work breaks and their importance. 

Keywords: musculoskeletal disorders, visual strain, psychological stress, primary care doctors, display screen equipment (DSE).

摘要

目的：對經常使用顯示屏設備（DSE）的醫生進行肌肉骨骼疾病、視覺疲勞及心理壓力患病情況的評估，調查DSE的哪些部件會導致上述病患，並研究上述症狀對工作表現的影響。

設計：描述性橫斷面問卷調查。

對象：新界西聯網家庭醫學科的62名醫生參加了本研究。

主要測量內容：採用源自“北歐（Nordic）問卷”的顯示屏設備（DSE）及計算機工作站用戶（醫生）標准化問卷，向經常使用顯示屏設備（DSE）的醫生收集有關肌肉骨骼疾病、視覺疲勞及心理壓力的數據。

結果：總應答率為77.4%。過去12個月中經常使用顯示屏設備（DSE）的基層保健醫生身體各部位不適的患病率為：頸部70.8%；肩部50%；腕部/手45.8%；背部45.8%；下腰部52.1%；眼睛酸痛68.8%。

68.8%的醫生報告了顯示屏設備使用中的問題。在用logistic回歸模型對混雜因素進行調整後，只有使用鼠標所致的腕部及手的症狀有顯著意義，顯示為OR值為17.43(95% CI為1.77-292.4，p值0.042)。

75%的醫生指出，各種關節問題或心理壓力為其工作帶來了額外的壓力，影響到工作效率和績效。

結論：在過去12個月中經常使用顯示屏設備（DSE）的基層保健醫生中，身體各部位不適的患病率較高。應培訓醫生們掌握使用身體的基本技巧，包括工作技巧、保持放鬆和工作節奏，以及正確使用電腦等等。還應熟悉工作中小息的方式及其重要性。 

主要詞彙：肌肉骨骼疾病，視力疲勞，心理壓力，基層保健醫生，顯示屏設備(DSE) 

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Introduction

With the rapid development of modern technology, visual display terminals or display screen equipment (DSE) have become a common part of the workplace. Display screen equipments can be defined as any alpha-numeric or graphic display screen, together with a keyboard and/or a mouse, regardless of the technical process used.¹ In the 1980s, office workers suffering from repetitive strain injury (RSI) due to prolonged DSE operation were largely reported in Australia.² A study reported associations between health disorders in the musculoskeletal system and use of DSE.³ Work-related musculoskeletal disorders referred to a wide range of inflammatory and degenerative diseases and disorders.⁴ Common musculoskeletal complaints among DSE users involved the back, shoulders, neck, and, to a lesser extent, the arms and legs.⁵ The prevalence of musculoskeletal symptoms among DSE users had been reported to be as high as 63%.⁶ A follow-up survey on the occupational health issue of DSE users in Hong Kong from various tertiary industries (including banks, data processing and analysis companies) showed the prevalence of musculoskeletal discomforts in the past 12 months were 62.5% in the neck, 60.1% shoulders, 16.0% elbows, 11.4% forearms, 25.0% wrists, 13.0% fingers, 40.1% upper back, and 40.2% lower back.⁷ Furthermore, musculoskeletal disorders have been associated with serious economic loss and decreased productivity.⁸ In the computer working environment, incorrect computer workstation set-up, prolonged work in fixed or awkward positions,⁹ seated and static work, and overuse repetitive movements have been identified as risk factors of musculoskeletal diseases (MSD). In addition, relationships exist between psychosocial factors (for example, social support from colleagues/supervisors) and musculoskeletal pain.¹⁰ Another study showed that high job demand, time pressure and more than 15 hours keyboarding per week were risk factors for forearm pain.¹¹ A study in the United States showed mental workload (doing extra tasks while typing) and time pressure (accomplishing extra tasks in the same time period) imposed increased burdens.¹² Another study has shown that mental stress could induce muscle tension and could contribute to the development of work-related upper extremity disorders.¹³ High levels of psychological demand and physical exertion were important predictors of future work-related repetitive stress injury.¹⁴ Conversely, maintaining an active lifestyle during leisure time was associated with a lower prevalence of work-related upper body repetitive stress injury.¹⁵ Furthermore, with the increasing awareness of such diseases by the general public, there is increasing recognition that such musculoskeletal disorders were work-related.¹⁶

 Visual discomfort has been linked to musculoskeletal complaints and work stress.¹⁷ A follow-up survey on the occupational health issue of users of display screen equipment in Hong Kong showed the prevalence of eye discomfort was consistently high (62%).⁷ The prolonged use of DSE with a reduced frequency of eye blinking and an increased rate of tear evaporation,¹⁸ which lead to dry eyes and associated symptoms such as ocular discomfort, fatigue and blurred vision. 

In summary, improper use of DSE can cause significant problems such as musculoskeletal symptoms, eye fatigue and psychological stress. These problems are preventable by good ergonomic design of equipment, furniture and work environment. 

The Hospital Authority took over all General Out-patient clinics (GOPC) in New Territories West Cluster (NTWC) since July 2003 and implemented the use of DSE in daily consultation. The above-mentioned studies and evidence from local and overseas countries had studied the effect of DSE on musculoskeletal complaint, visual strain and psychological stress in different occupations. No evidence currently exists on the effect of DSE on musculoskeletal complaints, visual strain and psychological stress among primary care doctors, who are an unique group who use DSE during their daily clinical consultations.

Doctors in the outpatient department (OPD) have to operate keyboards and use DSEs during their consultations everyday. Typically a doctor needs to use DSE 7 hours per day. For doctors attending evening clinics on the same day, they would be spending up to 11 hours per day. The daily work of the doctors not only requires frequent and prolonged DSE use, but they also have high mental workload (doing clinical decision while typing) and have to work under time pressure (accomplishing extra tasks in the same time period). 

Objectives of the study

The objectives of the study are: 

1. To study the prevalence of musculoskeletal disorders, visual strain and psychological stress among family medicine doctors who frequently use DSE.
2. To study the components of DSE which may contribute to musculoskeletal disorders, visual strain and psychological stress.
3. To study the impact of symptoms on their work performance.

Methods

This was a cross-sectional questionnaire survey on all doctors in the New Territories West Cluster, Family Medicine Department. The questionnaire survey collected data on: 

a)      The demographic information of the respondents;

b)      The prevalence of the following symptoms

•   Musculoskeletal symptoms
•   Eye strain
•   Psychological stress

c)       The doctors’opinions on DSE, workstation and their satisfaction of the DSE in use.

d)      Their work pattern. 

The doctors were invited to participate in the survey on a voluntary basis. Strict confidentiality and anonymity was maintained during data collection. Prior ethical approval for the study was acquired through both the NTWC cluster clinical and research ethics committee of NTWC cluster and the Survey and Behavioural research ethics committee of the Chinese University of Hong Kong.

62 doctors work in three Family Medicine training centres and seven GOPCs in the NTWC Family Medicine Department. All doctors in the Family Medicine Department were recruited into the study.

A standardized DSE and computer workstation users’ questionnaire developed from the Nordic Questionnaire was used for this study. The Standardized Nordic Questionnaire was developed by a team of Nordic researchers organized to create a simple standardized questionnaire that could be used for the screening of musculoskeletal disorders as a part of ergonomic programmes and for epidemiological studies of musculoskeletal disorders.¹⁹ The standardized DSE and computer workstation users questionnaire had been validated first by the pilot study from members of NTWC Family Medicine Occupational Safety and Health working group. The Statistical Package for Social Science (SPSS Version 16) was used for the study analysis. 

Results

48 completed questionnaires were collected from 62 doctors in the department and were used for the data analysis. The overall response rate was 77.4%.

The prevalence of musculoskeletal disorders, visual strain and psychological stress in doctors who frequently use DSE is shown on Table 2. For musculoskeletal disorders, the top five self-reported symptoms were: neck 70.8%, lower back 52.1%, shoulder 50%, wrist and hand 45.8% and upper back 45.8%. Furthermore, around 20.8-31.3% physicians reported trouble at anytime in the past 7 days for the above symptoms. As the result of the symptoms, more than 10 percent (range from10.4-14.6%) physicians reported that the symptoms prevented them from doing normal activities in past 12 months.

Table 1: Demographic characteristics of the respondents

* Mean [Standard deviation]: 1.042 [ 1.129]hours

Table 2: Prevalence of musculoskeletal symptoms, eye strain and psychological stress in the past 12 months, their duration and functional impairment

The prevalence of elbow and lower limbs symptoms was 16.7% and 4.2-8.3% respectively. 

68.8% of physicians reported sore and tired eye symptoms. 39.6% reported problems in the past 7 days, and 16.7% of them were prevented from doing normal activities in the past 12 months. Meanwhile, 27.1% of physicians reported blurred vision and 12.5% of them reported problems in the past 7 days, and 6.3% of them were prevented from doing normal activities in the past 12 months. 

56.3% of physicians reported psychological stress and 18.8% of them reported problems in the past 7 days, with 10.4% of them were prevented from doing normal activities in past 12 months. 

From Table 3 & 4, we could observe that 87.5% of respondents did not take regular short breaks during their working hours. Instead, they kept the same posture for an extended period of time (mean 3.62 hours).

Table 3: Descriptive statistics for workload /exposure variables

Table 4: Descriptive statistics for taking of breaks from DSE work

The majority of doctors (68.8%) identified problems in their current DSE usage (Table 5). Moreover, most (75%) doctors pointed out that joint problems or psychological stress caused extra stress in work and had a direct or indirect impact on their work efficiency and performance. More than 50% reported that the use of keyboard, mouse or printer contributed to bodily disorders. (Fig. 1) 

Table 5: Problems perception of DSE and reasons for dissatisfaction on DSE components

Most doctors (72.9%) reported that they were not trained about when and how to adjust their workstations (Table 6). Most doctors (87.5%) reported that they had not attended any workshops or seminars on workstation or DSE. Many (68.7%) reported that they did not know how to seek assistance on DSE modification and 60.4% of them reported that they had not considered to seek assistance on DSE modification.

Table 6: Data on physician information on occupational safety education

The components of DSE which may contribute to musculoskeletal disorders, visual strain and psychological stress in doctors are shown in Table 7.

Table 7:  Univariate analysis * of risk factors and 3 groups of symptoms [the musculoskeletal pain, the eye strain (including sore tire/eyes with or without blurred vision) & the psychological stress]

* Chi-Square test was used for data analysis, except any cell had expected count less than 5, than Fisher's Exact test would be used.

With the logistic regression model and control for potential confounders, the use of mouse had a significantly raised OR 17.43 (95% CI 1.77-292.4, p value 0.042) for wrist and hand symptoms. 

The potential confounders included the following: physicians’ (35.4%) reported history of musculoskeletal sprain or injuries involving various parts of the body, reported history of visual disorders (72.9% majority of them due to myopia) and reported computer-related activity outside work (64.6%, mean was 1 hour).

The impact on the physicians’ performance was statistically significant for the symptoms of neck, shoulder, wrist and hand and sore eye, which caused extra stress in work.  

Discussions

The prevalence of complaints in various body parts of the doctors who frequently used DSE in the past 12 months were compared to the findings of the follow-up survey on the Occupational Health Issue of DSE users in Hong Kong⁷ on Table 8.

Table 8:  Comparison between the result of our study with the follow-up survey on Occupational Health Issue of DSE users by OSHC Hong Kong

Workers with occupational musculoskeletal disorders had poorer self-perception of physical and mental health.²⁰ In addition, the prevalence of psychological stress in the study was 56.3%. Psychological factors such as high job demands, mental workload, time pressure and more than 15 hours of keyboarding per week were identified as risk factors for forearm pain.²¹ 

68.8% doctors reported problems in current DSE usage. With the use of logistic regression model, the mouse usage showed a significantly increased OR of 17.43 (95% CI 1.77-292.4, p value 0.042) for wrist and hand symptoms. Poor placement of both the keyboard and the mouse increased the risk of pain in all body regions studied.²¹ Working at least 5.6 hours a week with a computer mouse increased the risk of musculoskeletal symptoms in the shoulder joint, elbow, wrist and hand.²¹ In addition, around 87.5% of physicians did not take breaks from DSE work. They would keep the same posture for an extended period of time and so increased the risk of musculoskeletal symptom after prolonged mouse usage. Rest and exercise breaks for computer users were shown to increase the likelihood of recovery from symptoms: 55% versus 34% in users without breaks.²² 

Moreover, most doctors (72.9%) reported that they were not trained about when and how to adjust the workstation. The primary care doctors should be provided the education on occupational safety and hygiene with the usage of DSE to prevent the development of musculoskeletal symptoms. The finding from the local Occupational Health Issue survey which showed that 54% computer workers adopted a leaning forward or backward posture position when looking at the computer monitor.⁷ Most operators were not aware of the height to which furniture should be adjusted and most were reluctant to change the setting for fear of losing the previous setting that conferred an optimal degree of comfort.⁷ 

There are limitations and potential biases from the study. The small sample size of the study affected the generalization and statistical power. The relatively young age of the respondents (65% were younger than 35 year old) may have affected the prevalence of symptoms. There was a lack of objective work load assessment and possible recall bias on average work hours and the average patient load. Finally, the findings do not represent the majority of primary health care doctors in the private sector — most are not frequent users of DSE in their daily practice. 

The basics for prevention entail the design of equipment and tasks, the organization of work, the work environment, training and education and the development of health and safety policies. Workers must have the chance to learn the basic skills of body use including work techniques, relaxation and rhythm, the different types of work breaks, the reasons for taking them, and the correct use of equipment.²³ There was a consensus that occupational musculoskeletal disorders were major problems leading to adverse health and economic consequences. The development of interventions such as workplace alterations could help eliminate some risk factors, such as awkward posture, excessive force, and high repetition rates. As the number of doctors using computers increases over time, injuries, ill-health and their consequential costs related to improper use of computers can be expected to increase if no action is taken. 

Acknowledgements

Funding: no funding was received from any commercial or pharmaceutical company for this study.

 Technical assistance: statistical advice from NTWC cluster statistician and Dr Martin Wong Chi Sang, Associate Professor of Department of Community and Family Medicine, CUHK.

Participants: Dr Wong Hung Yung and members from NTWC Family medicine Occupational Safety and Health working group for their valuable advice on the questionnaire design and pilot study. 

We would like to thank all the medical staff working in our department who had actively participated and contributed in the study.

Key messages

1. The prevalence of complaints in various body parts of the primary care doctors who frequently used DSE in the past 12 months was high [up to 70.8% for neck symptom].
2. The mouse usage was significantly associated with symptoms of the wrist and hand.
3. During their work hours, 87.5% of the respondents did not take regular short breaks and they would keep the same posture for an extended period of time.
4. Most doctors [72.9%] reported that they were not trained about when and how to adjust the workstation. The majority of doctors [87.5%] reported that they had not attended any workshop/ seminar on workstation or DSE.
5. Workers must be given a chance to learn the basic skills of body use including work techniques, relaxation and rhythm, the different types of work breaks, the reasons for taking them, and the correct use of equipment.

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References