Abstract
Introduction
Musculoskeletal disorders (MSDs) can be defined as an injury to muscles, nerves, joints, connectivetissues like ligaments and tendons, or any other bodily structures that support or comprise the neck, back, and limbs [1]. MSDs cause inflammation and sufficient discomfort to impede one’s routine functions, and they are conditions which worsen over time. MSDs are prevalent across a wide swath of occupations, as well as those with heavy biomechanical loads, such as manufacturing and factory jobs, and also those with lighter loads such as office work [2, 3]. These issues have been observed to develop more frequently among people who rarely or never engage in physical activity and have unsuitable ergonomic situation during working time, as opposed to those who do so with some degree of regularity and frequency [1]. Musculoskeletal disorders are becoming more and more prevalent amongst office workers, who comprise a large segment of the workforce in Malaysia [4]. According to the National Institute of Occupational Safety and Health (NIOSH), approximately 61% of the Malaysian workforce is involved in work which requires the use of computers, and the number of office workers in the nation continues to grow [4]. Malaysia is a country which has seen a great deal of development and industrialization in recent decades, and as such, it has a large number of workers in various fields with jobs that require them to spend extended periods of time remaining sedentary while working, often sitting for hours in front of computers and in unfavorable ergonomic conditions [5]. There are many physical injuries and disorders among office workers, who sit for a long time and do not perform enough physical activity. The injuries can cause absences and suffering during work time, with individuals feeling tiredness and pain in their limbs such as neck, lower back, shoulder, and knee.
Monitoring MSDs within a given population requires accurate and dependable methods, also using clinical measurements is expensive and time-consuming. So an easier way to recognize these disorders among office workers is required. Subjective measures like, questionnaires or the utilization of instruments like the Goniometer to check range of motion are common methods widely used when attempting to assess MSD. The use of questionnaires is the most common way to do this in epidemiological research involving a large number of participants, as the cost of doing so is generally low, relative to other available options [6]. Before this, there was a Nordic questionnaire to determine the MSD, but it was deemed too long and too general. An English version of the CMDQ was available, but it was difficult for some of the local people to understand. Therefore, it was necessary to create a Malaysian version of this questionnaire.
In the late 1990s, Dr. Alan Hedge of Cornell University, along with a team of ergonomics graduate students, developed the International Musculoskeletal Discomfort Questionnaire (MSD), which is now considered one of the most important questionnaires in the field of musculoskeletal disorders [1]. There are other posture-targeting questionnaires that preceded the CMDQ but what makes the CMDQ unique is that, in addition to assessing the frequency and severity of discomfort, it also assesses how much musculoskeletal discomfort interferes with the ability to work.
The questionnaire was divided by gender and made available in 3 forms: Sedentary workers, standing workers, and hand symptoms. The validity and reliability of this questionnaire has been examined extensively in a number of countries; however, it has not yet been validated in a Malay-speaking population. Therefore, no Malay version of the scale is available and there is a need to develop the scale to examine MSD in Malaysia. Also, a Malay version of the scale is necessary to facilitate studies in the field. Therefore, we are attempting to bridge this gap and further examine the use of this questionnaire by translating and validating a Malay-language version of the CMDQ sedentary form for use in Malaysia.
Methods
Translation procedure of Cornell Musculoskeletal Discomfort Questionnaire (CMDQ)
There was a sedentary version and a standing version of the CMCQ and in this research we used the sedentary version. The necessary educational conversions were performed in accordance with the guidelines provided by the International Consensus Group. “Forward” and “backward” translations were performed on the version of the original CMDQ intended for sedentary office workers from July to September 2014. The original questionnaire was first translated into Malay by two separate translators whose native language was Malay, and who possessed a high degree of fluency in English. One of the translators was an occupational professional and the other an orthopedic professional, both familiar with Anatomy and Physiotherapy terminology. Slight adaptations were made at this phase to make certain conceptual correspondence. The translated version was compared by two independent translators who sought to identify differences in comparison with the original version of the questionnaire. No significant differences were identified and no concepts that did not directly translate into the Malay language. After the 2 versions of the translation had been compared, discussed, and adjusted, a preliminary Bahasa Melayu version of the CMDQ was agreed upon.
A reverse translation of the raw Malay-language report into English was performed by an independent, specialized translator who was fluent in Malay, and whose first language was English. Then, there was a comparison between the newly-translated English and the original version of the questionnaires, and a temporary draft of the Malay-language questionnaire was prepared for trial measuring intended to identify probable issues of comprehension among the general population [6].
Pilot study
The preliminary Malay version of the CMDQ was answered by 7 local males and 7 local females. These subjects were working in a private company as cleaners, aged 30 to 45, with different religions (Muslims, Bodyists and Christians) and a low level of education or no education. The questions were read for the non-educated subjects by a local person. The main aim of this pilot study was to check for cultural, educational, language and regional problems, and so the subjects were asked to make a note beside what they considered to be unclear or vague questions. The results of pilot testing and related interviews were summarized and any problematic items were changedappropriately.
After a subsequent cultural, educational, language and regional adaptation of the questions asked, a comprehensive and conclusive version, referred to as the Malay-language version of the CMDQ (CMDQ-M), was decided upon. It was clear and easy to understand, allowing anyone who is literate in the Malay language to self-administer the questionnaire.
Sample size
As compared with previous studies of adaptation across cultures, as well as reliability and validity, the test-retest reliability of the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) in the Malay language was adequate; the Kappa coefficient range of 0.56–0.97 demonstrated moderate to near-identical correlation between responses to the first and second questionnaire for all body parts tested. The sample size was calculated based on “Sample Size Tables for Clinical Studies” [7], for both reliability and validity. with an assumed ICC = 0.75 (Intraclass correlation coefficient), a desired 95% CI (confidence interval) width of 0.2 and considering 25% for drop-out rate therefore a total 94 subjects were included for reliability testing. The Sample size calculation for validity testing, based on literature for CMDQ Spearman correlation coefficient with a correlation coefficient(ρ) of 0.4, significant level of 0.05, power of 0.80 and considering 25% for drop-out rate, was 105 subjects.
Participants
This study took place in the University Putra Malaysia. All participants were university employees who worked in the security office whose native tongue was Malay. In total, 115 volunteers (with different levels of education and different religions) participated in this study, though 10 of those individuals were unable to fully complete the study. The criteria for inclusion consisted of the following: Adults – both male and female – who (a) were between the ages of 25–50, (b) self-identified their ethnicity as Malay, (c) did not suffer from any physical conditions or disabilities that would place limitations upon basic physical activities, and (d) possessed a level of literacy that would allow them to respond to the questionnaire. All procedures performed in studies involving human participants were in accordance with the 1964 Helsinki declaration, also all participants provided written consent prior to taking part in the study [8, 9]. The agreement letter for translation of this questionnaire was obtained from the original developer of this questionnaire, Cornell University, USA.
Data collection
Data was collected from July to September 2014. Participants were approached before working time, and were required to provide their written consent. Training was also provided on how to properly administer the CMDQ-M for the researchers involved.
The CMDQ-M questionnaire was spread among subjects on the first day, and they were instructed to avoid any alteration of their daily routines for the duration of the data collection [10]. They had 10 minutes time to fill the questionnaire. The participants were then contacted once more to completeCMDQ-M for a second time two weeks later, the results of which were used to measure the reliability of the survey questionnaire.
Validity
Content validity
Three experts (two from Iran and one from Sharjah) with PhD PT degrees reviewed the back translation into English from the Malay language version of the Cornell Musculoskeletal Discomfort Questionnaires (CMDQ) that was done by two experts (two from Malaysia, one of them with a PhD degree in Occupational health and the other holding an MD degree in orthopedics). This survey was conducted to determine if the questions enabled answers relevant to the underlying concepts they were designed to investigate could be obtained. A committee was formed to review the translation, consisting of professional translators, in addition to an occupational health specialist and a company doctor, the latter two of whom had prior knowledge of and experience with the area of research being done. Both the original version and newly translated draft of the questionnaire were reviewed by the committee. The committee agreed that insertion of side-definitions in aforementioned body parts (the insertion of definitions for body parts with which some people may be unfamiliar), along with adding the phrase “answer for every body part” to the frequency scale and modifying clothing on the body diagrams to reflect local attire were appropriate revisions and addenda. Upon completion of the review, a preliminary final Malay version of the CMDQ was drafted, and a consensus was reached regarding its essential equivalence to the original English in terms of idiomatic expressions, conceptual and semantic equivalence, comprehensibility and practical applicability. Five subjects of varying backgrounds subsequently reviewed the preliminary final Malay version of the CMDQ and found it to have a high level of face validity, at which point the committee review stage wascomplete.
Concurrent validity
As a validation of the Malay-language version of the CMDQ (CMDQ-M), participants were required to complete a Visual Analog Scale (VAS) to measure validity which ranged from ‘0’ (“No pain or discomfort”, to 100 (“Severe pain”) [7]. The hypothesis was that those who reported pain or discomfort in the VAS would logically also do so in the CMDQ-M, and likewise those participants who reported no pain or discomfort in VAS would also be expected to state “Never” in their response to the CMDQ-M survey. The correlation between responses on the two frequency scales was measured using the Kappa coefficient, and the Spearman correlation coefficient was used to assess the relationship between scores on the severity scales [11].
Face validity
Interviews were conducted with half of the participants (via random selection) who were willing to discuss their experiences of MSD using the questionnaire of Erdinc et al. [1]. Participants were asked to complete an interviewer-administered version of the CMDQ-M with the specific request that they stated any difficulties they had in understanding or completing the questions. All comments were taped, transcribed, and subjected to content analysis - which entailed reading through the data and identifying recurrent themes or those areas which were emphasized as important by the interviewees. This method was undertaken for all sections of the questionnaire.
Reliability
In order to measure the internal consistency and reliability of the CMDQ-M, participants completed the questionnaire twice. The interval between testing ranged anywhere from seven to ten days, as suggested in prior studies. The Kappa coefficient was utilized to assess the test’s reliability, with separate evaluations of scales for severity, frequency and interference. Construct validity was assessed through factor analysis. Cronbach’s alpha statistic was also used to measure internal consistency (recommended value α≥0.70).
Statistical analysis
Statistical analysis was done with the Statistical Product and Service Solutions (SPSS) software (IBM SPSS Statistics 21.0), with the significance level fixed at P < 0.05. Where applicable, independent tests and Mann–Whitney U tests were used to measure inter-gender variance [12]; however, the majority of musculoskeletal discomfort variables showed little to no difference between men and women, leading the analyses that followed to be conducted without distinguishing by gender.
Spearman’s correlation coefficient was used for analysis of the test–retest reliability of the CMDQ-M, and further assessment was performed by a single-measure ICC (1-way random effects model). This model represents the overall variance percentage which can be accounted for by the variations between measures. Cohen’s κ coefficient was used to study the musculoskeletal discomfort categorization harmony of test–retest dependability, while assessing the validity of musculoskeletal discomfort was done by Bland and Altman plots 24.
Results
Demographics
The majority of those participating in the study (83%) were male, and 100% of the participants were Malaysian. Ages were all within the range of 25 to 50 years, the mean age being 36.4 ± 10.5 years. All participants had similar occupational backgrounds. Slightly less than half of the participants (41%) had secondary school education, but a small percentage (3%) had not been formally educated (Table 1).
Content validity
Based on the opinion of the experts, the back translation in all items was very strongly (90 % +) matching the original English version of the CMDQ. This is expected in the sense that almost all of the terms used in the original as well as the Back Translation from Malay to English versions of the mentioned questionnaire are standard names routinely used in physical therapy and ergonomics and the perfect match expressed by all 3 of us is on that basis (Table 2).
The overall Kappa coefficient range of 0.686–0.923 with relation to both VAS responses and CMDQ-M frequency scale responses indicated substantial to near perfect agreement across all body parts [11]. Spearman correlation coefficients likewise displayed a positive correlation between VAS and CMDQ-M scores, ranging from 0.570–0.893 across the full spectrum of body parts (i.e p < 0.01).
Concurrent validity
The associations observed between the CMDQ-Mand VAS-M for overall, severe, moderate, and mild pain were moderate ones (rs = 0.309–0.466, P < 0.01).
However, both tests displayed the same proportion of highly active groups, while inactive groups differed based on method; the highest was VAS-M(14%) and CMDQ-M (5%). In terms of the classification of musculoskeletal discomfort levels, a significant correspondence could be observed between the CMDQ-M and VAS-M (χ2 = 21.217, P < 0.001) (Table 3).
Face validity
Fifty seven participants (from 115 participants) were interviewed and completed the CMDQ-M in the presence of the interviewer. These participants made comments on how they understood the questions. On average, these respondents took eight minutes to complete the CMDQ-M. Only one participant needed further explanation about the questionnaire on MSD. All the other the participants commented positively on the statements‘ orderly arrangement, clarity, representation of MSD prevalence and simplicity, confirming the high degree of face validity.
Two-week test–retest reliability
Kappa coefficients fell in the ranges of 0.690–0.949 for frequency, 0.801–0.979 for severity, and 0.778–0.944 for interference scales. Based on the earned data, conformity between responses to the repeated testing for each scale was fell in the range of moderate to near-identical agreement [11]. Among 60 Kappa coefficients examined across all three scales, 6.7 % showed moderate agreement, 71.6 % had substantial correlation, and 21.7 % were at almost levels of agreement. In terms of agreement for particular body parts, test-retest responses for lower back fell into the moderate agreement range, while test-retest responses in the remaining body parts showed either substantial or near-perfect agreement across all three scales. Cronbach’s alpha statistic showed results of 0.876 for frequency, 0.895 for severity and 0.875 for interference scales, indicating a high level of internal consistency of the CMDQ-M [13] (Table 3).
Discussion
All who participated in the study volunteered to do so and were representative of the general population due to their varied educational and occupational backgrounds. Nevertheless, the comparatively small number of women involved did not allow for possible variations in PA patterns based on gender to be seen. In the adaptation of the original questionnaire into a new cultural context, the ultimate goal was to produce a pellucid Malay version of the CMDQ which could be readily understood by anyone with literacy in the language among three religions – Muslims, Bodyists and Christians. Also, we tried to adapt the questionnaire bearing in mind cultural, educational and language differences. To this end, it was ensured that the guidelines put forth by Beaton et al. (2000) were adhered to throughout the translation process [14]. A team of researchers from multiple backgrounds, comprised of linguistic as well as healthcare professionals took part in forward and backward translation and synthesis, as well as a full committee review and pretest of the questionnaire. In places where direct synonyms did not exist for specific body parts in Malay – notably the upper arm, forearm, thigh and lower leg – appropriate equivalent expressions were substituted (e.g. “between shoulder and elbow” for upper arm). The Malay equivalent of “Answer for every body part” was added into the frequency scale, and in order to suit the modest and religious Malay culture, diagrams of the human body were altered with the addition of clothing [15]. Due to a number of incomplete responses on the preliminary test, the layout was adapted in a way that allowed participants to be more easily familiarized with the body parts and scales being tested; lines were added to separate the body parts and sections from left to right, and questions related to the severity and interference scales were emphasized by writing them in bold [16].
The percentage of incorrect or incomplete responses, which in preliminary testing was at 39%, reduced by 8.9 % during the validation process, placing it within the range considered satisfactory for a self-administered questionnaire. This result indicated that the aforementioned modifications were acceptable and that the final version of the CMDQ-M was deemed relevant and useful to a literate population of Malay speakers.
Examining its psychometric properties showed that the CMDQ-M demonstrated strong validity in terms of agreement between discomforts reported in the VAS, while the CMDQ-M frequency scale was substantially high. Additionally, VAS scores displayed a significant positive correlation with severity scores on the CMDQ-M across the entire body. The re-testing reliability and internal consistency levels were also considered sufficient. Kappa coefficients demonstrated considerable and nearly impeccable agreement between initial testing and re-testing responses on nearly all scales. The exceptions to this were the lower back and the severity scale of the back. These were demonstrated to be at a moderate level of agreement. The implication of these results is that the reliability between initial and follow-up testing can be considered sufficient in terms of all three scales, in addition to the high level of internal consistency indicated by high values of Cronbach’s alpha statistic [17]. Therefore, the conclusion reached was that the CMDQ-M was a sound and dependable means of data collection.
Having a sound means of data collection is vital to the execution of valid assessments in ergonomics research [18–20]. The research presented in this paper resulted in a readily applicable and reliable Malay-language version of the CMDQ-M, which could be effectively utilized in such a way in MS discomfort assessments among Malay-speakingpopulations.
Conclusion
This research was concerned with the translation and cultural adaptation, and assessment of the validity and reliability of the CMDQ for the Malaysian subjects. The Malaysian version of CMDQ should be a useful instrument to assess different aspects of MSD among office workers, with applications in both clinical research and practice. However, this study was conducted with sedentary staff only employed in government companies. Moreover a large number of citizens in Malaysia are Chinese, with different attitudes to working and health, additional validation and analysis may be required before the CMDQ can be considered a completely validated data collection tool for other research in Malaysia.
The implication of this study is that the CMDQ is a valid and sufficiently reliable method for evaluating various areas of musculoskeletal discomfort with differing levels of intensity. This test is appropriate for use in medical research when the primary focus of the study relates to varying levels of frequency, intensity and duration of musculoskeletal discomfort. Nevertheless, as the staff are often worried about losing their job and there is not a standard and easy method for them to report any pain or disorder, the potential for underestimation of the problems remains high within the context of self-assessment.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interests with respect to the research, authorship, and/or publication of this article.
Funding
There was no grant or funding for this research and it was done by the personal budget of researchers.
Footnotes
Acknowledgments
Authors are grateful to Prof. Alan Hedge for his permission to adapt CMDQ in Malay language.
Authors wish to thank Dr. Hossein Karimi, Dr. Azar Moezi and Dr. Mehdi Dadgoo for their involvement in validation of the tool process. We would like to express our special thanks to Professor David Pyne, Australian Institute of Sport, Canberra, Australia for his assistance with the manuscript. The authors also thank the staff at the Security Office of University Putra Malaysia for their participation and cooperation.