A Human Factors and Ergonomics questionnaire to identify causes of Work-Related Musculoskeletal Disorders in construction workers

Introduction

Work-related musculoskeletal disorders (WRMSDs) include a wide range of health problems and they are a recognized fundamental problem in the world. Generally, WRMSDs are one of the leading causes of injury and disability industrialized and industrially developing countries [1-4]. Furthermore, WRMSDs are one of the social indicators health which provides largest deviations between the technologically advanced countries and emerging countries [5].

WRMSDs are a serious problem in industrialized countries[1] and are a good example of the consequences of failing to take into account the requirements of ergonomics. They are the most common health problem in Europe, affecting millions of workers and are the leading cause of absenteeism in practically all EU member countries. In some states, TME's represent 40 percent of workers compensation costs and to 1.6 percent of gross domestic product (GDP) [6, 7].

In construction sector, workers can develop a wide range of inflammatory and degenerative diseases associated with the disruption caused by body structures of muscles, joints, tendons, ligaments, nerves, bones and circulatory system, primarily caused or aggravated by work and the effects of the environment. The result is an increased pain and functional impairment which may affect the neck, shoulders and upper limbs. Furthermore, these disease and WRMSDs are the result of exposure to various risk factors such as social, organizational or environmental, and biomechanical conditions related to work procedures such as handling heavy loads or performing repetitive movements [5, 8-10].

WRMSDs attend to multifactorial aetiology related to many variables like genetic, environmental and behavioural factors. Because of this aetiology, only a few professional diseases are recognized as occupational diseases [11]. For example, between 2001 and 2007 most prevalent musculoskeletal diseases in Europe were carpal tunnel syndrome, diseases caused by overexertion of the muscle and tendon insertions and diseases due to overuse of the tendons [12]. Despite the multifactorial nature of musculoskeletal pathologies that construction sector workers develop, there are one or more causes that explain the nature of the injury. Therefore, there are unless one or more causal relationships that indicate construction sector workers may develop musculoskeletal injuries related to the work they are performing.

Methodology

This article uses semi-structured interviews as basis of the study. An interview is a procedure designed to obtain information from verbal responses a person gives oral questions [13] in order to investigate the facts, knowledge, opinions, judgments and motivations.

The semi-structured interview applies a questionnaire which provides a complimentary guide for the interviewer. Accurate information on specific populations is obtained by the interview [14]. Thus, the interviewer - using the questionnaire - is able to set personal standards during the interview, by applying a pragmatic communicative approach, or/and a discourse analysis [15].

In this study, an semi-structured interview designed questionnaire was chosen because of the following circumstances [16, 17]:

· The sample consists of people who can read and write easily. They do not understand exactly what is being asked, so an interviewer is required to clarify the issues. There are no languages barriers, since respondents considered are all of Spanish nationality. Also, it is used a clear and simple verbal language.

· The research interests are clear and well defined.

· The interview may give objectivity to the questionnaire. For example, the interviewer may explain issues that interviewees do not understand. In this regard, a skilled interviewer should demonstrate qualities such as impartial and open-minded, not prejudiced, who may respect the opinion, etc. [18]. Conversely, the questionnaire may avoid the subjectivity of the interviewer, because the interview must be limited to the raised issues [19].

· To carry out the interview as a means of obtaining descriptive epidemiological data. A questionnaire scales and standardized questions may avoid the main disadvantages related to the use of the interview.

· The interview through questionnaire overcomes the subjective parameters, trying to clarify as closely as possible the questions.

· Interviewees do things differently in the past, which is why we previously established a period of observation and measurement of activities.

Moreover, specific questionnaires recourse to the fact that aspects (that may be readily appreciated as the initial pain and disability scores) allow to confirm the overall health [20]. That is, specific questionnaires start with the relationship between the WRMSDs and pain as the main reason for prolonging processes temporary disability [21].

When a personal interview conducted is provided, the risk involved in the use of documented material is defeated without considering the critically sense [22].

The interview was conducted for a population of 150 workers, where 34 workers (22.6%) reported that they felt musculoskeletal discomfort related to their work, revealed professional musculoskeletal diseases or suffered accidents relative to WRMSDs for the past two years. To conduct this interview, the following objectives were taken into account:

• 1. Recognize certain aspects of the study population.
• 2. Recognize the type of work done.
• 3. Provide trusted information in relation to musculoskeletal symptoms [23]:

· Examine musculoskeletal disabilities that have not generated in an active population.

· Check data by other techniques with the information provided by workers.

· Apply a standardized method for the determination of WRMSDs and compare obtained data with the group, activity, and the assessed risk factors.

· Understand the problems and muscle ailments with work-pattern affecting a sample of construction sector workers.

· Promote the active participation and consultation of employees to the approach of improving the ergonomic environment and conditions.

Description of the questionnaire

The interview provides both therapeutic and social aspects, in order to serve to collect social data in the demographic profile of selected workers [24].

An effective tool for the development of semi-structured interview is the "Nordic Questionnaire." As a difference from other methods, the "Nordic Questionnaire" may handle the interview on labour population even when the pain is not a disability [23].

The "Nordic Questionnaire" is complemented by an interview in order to achieve results that may reveal aspects related WRMSDs risk of injury [20]. Moreover, the "Nordic Questionnaire" offers a good balance between pain, WRMSDs and temporary disabilities processes [21].

The questionnaire is described by a map divided into regions, where the interviewed is asked to respond by pointing “what part of its body has / had aches, pains, or problems”.

Accordingly, the questionnaire should be formulated anonymously to all information collected is used as a method of finding possible factors causing fatigue at work. The purpose of the questionnaire is to improve the conditions under which the tasks are performed, in order to achieve greater welfare for the sample and improve work processes.

In this study, there are incorporated some extras questions at "Nordic Questionnaire", which are formulated as response rate following a scale with four points, one of which is the zero [25]. This enables the qualification and quantification, numerically [26].

Finally, the interview includes the following issues to identify signs of WRMSDs:

Question P1: Refers to the age of the sample.

Question P2: Gender of the sample.

Question P3: Working Group. Hence, different jobs have included: HVAC networks, equipment and refrigerant piping, electrical networks, pipe and PCI, and fine masonry.

Question P4: Activities performed more often during the past two years by workers.

Question P5: Time working in this work.

Question P6: Factors believed to increase the development of WRMDs. It proposed the following risk factors:

· Type of biomechanical factors. Fatigue. The limits of the body energy are exceeded.

· Biomechanical risk factors dues the application of physical force required for the development of the tasks.

· Biomechanical risk factors dues to the inadequate working postures (awkward, static, or static pure postures) affecting the musculoskeletal system.

· Biomechanical risk factors. Direct mechanical pressure on body tissues (due to pressure neuropathies postures and loads).

· Biomechanical risk factors for repetitive work: Works which involve short repetitive tasks.

· Biomechanical factors such kind of repetitive. Highly repetitive movements of the lower and the upper limbs.

· Biomechanical risk factors for lifting, handling and thrust loads: Push heavy or awkward loads are performed.

· Factors organizational type. Lack of ergonomic training and cultural awareness.

· Factors organizational type. Monotonous work.

· Factors organizational and community type. The tools and machines are not fully adapted to the required task.

· Factors organizational and community type. Compensation systems: Work is underpaid.

· Factors organizational and community type. Lack of use of related techniques: Index search solutions, legislation ...

· Hygiene factors. Body vibrations.

· Factors organizational type. Supervision and leadership is lacking.

· Factors organizational type. Environmental influence: Cold or hot environments works.

· Factors organizational type. Lack of extra conditions that could help like physical training, massage, acupuncture, or relaxation techniques, between others.

· Psychosocial factors and personality type. Poor interpersonal relationships (p.e. mobbing and unnecessary stress by time pressure).

· Organizational factors and psychosocial. Pattern of work: No free to take a break, job autonomy.

· Psychosocial factors kind. Work schedule. Initially, stress limits (set by the pressure of time) are overcome.

In the questionnaire has been excluded the factors such as the genetic factor and the personal factors, which may have an intrinsic value in itself and would be subject to parallel studies.

Question P7: During the two last years: Have you ever had a musculoskeletal disorder associated with the work, and if so, the medical diagnosis?

Question P8: Have you required time off work due to the conditions (ergonomics and biomechanical conditions).

Question P9: In case that you have not had to miss work, indicate if you suffer pain or discomfort related to your work. Specify the body part affected.

Question P10: In case that you felt discomfort, indicate how often you feel this discomfort.

Question P11: It Duration of discomfort time.

Question P12: Indicate a qualification or scale to the inconvenience related to the question P10.

Validation, Reliability and Reliability

The validity of the questionnaire is the ability to measure what it claims to measure. In this study, the content and external validity have been identified.

Content validity of the questionnaire-interview is given by the fact that data are compared with other questionnaires recognized as suitable for this purpose and conform to reality without distortion. In this case, which has decided to use its simplicity and validity is the "Nordic Questionnaire." Being introduced additional questions in this questionnaire, a pilot test was applied to five participants, who were provided voluntarily. The questionnaire is conducted by a personal interview. Regarding external validity, this character is given by the approach of the hypothesis of the survey and the research itself, since the development of it corroborates data have been analysed by other techniques. Moreover, using recognized scales, such as the "Likert Scale" and "Borg Scale" scores, the possibility of building the instrument used for measurement and analysis of attitudes is provided, allowing analysis the type of activities and factors which may develop WRMSDs and functional classification of worker consultation, and assessment of the damage. The last two in this case, data from the accident investigation or data are reviewed by the workers questions about other accidents within the selected period. The functional classification and valuation of damage is described by the medical service in this case the operator has attended [27].

Second, the feasibility and sensitivity is given by the ease with which the questionnaire to be applied in different situations and subjects, which is why we have proposed the use of an interview to different groups of subjects in the area of ​​mechanical installations .

Finally, reliability is given by the internal consistency, which is defined by the characteristic of the Cronbach's alpha coefficient, which indicates how different elements of the questionnaire measure the same variable. This questionnaire is given by the elaboration of issues with items rated using a Likert scale. For the full survey, Cronbach's alpha obtained by the IBM SPSS Statistics, v.19 program., Resulted in a value of 0.591 for the issue P4, which, though still a little low, it can be explained as the matter has been established for all workers who are actually subject to different processes, which is why many of the activities that have been indicated as never (0). Moreover, the question P6 have registered a value for the sample Cronbach 0.715, which indicates an acceptable level and have remained thus all items.

All other issues does not require the application of Cronbach's alpha as it part of the standardized questionnaire "Questionnaire Nordic".

Results

The results obtained in the interview below:

Question (P1). Age range. The results indicate that the average percentage of respondents is between 25 and 54 years. Indicated an age range on this scale from the minimum age limit for a worker begins working in construction (18 years), until the retirement age (65 years).

Question (P2). Gender. The sample is only male.

Question (P3). Group working. Different jobs were including related to the sample: HVAC networks, equipment and refrigerant piping, electrical networks, pipe of PCI and fine masonry. It should be noted that 100% of respondents from the group electrical network have between 25 and 54 years old. The smallest percentage recorded in the group is mounting channels, with 3% of population 55 to 65 years old.

The workers largest percentage belong to the group "installations ductless air conditioning", with 31%, and the lowest percentage of "fine masonry", with 9% of the total respondents.

Question (P4).  The sample was asked about the activities, which have been making more often during the past two years. Many of these workers have been making very different jobs or works, which is typified by Question (P5). The sample provides that 32% of the interviewed workers take less than a year in this position or work. As data, it was observed that 77% score, the higher was the so-called "carrying loads", followed by 73% for operations "grinder and cut with cutters on the ground." Activities that are answered as done most often are "screwed ceilings" and "measuring and marking", which were included as repeated in the flow chart and processes.

The results of the first two cases are interesting; as well in this study has the following aspects:

· Workers have mechanical loading means to do their job.

· For this study tables (for cutting) and unique spaces (to move and develop parts).

· 32% of the interviewed workers, as shown in the question P4, have been doing during the given period another job related to construction, but not mechanical building.

For analysis of the scores were considered the following options following Likert scale. Never, it has been rated with a "0" Rarely, it has been rated a "1" Often, it has been rated a "2" Very often, it has been rated a "3".

Thus, the percentage is set to 100% maximum ratings of 102, resulting from the multiplication of the maximum (3) by the number of respondents (34).

In the Question 5 (P5), corresponding to Figure 1 shows that between percentage of respondents, 33% Takes less than a year working on the same job and 13% take between 1 and 5 years, e.g., are part of a population that has not been in this position, therefore, is not experienced.

Figure 1. Scores representing activities often and very often during the past two years.

In Question (P6), the operators on what are the factors that increase the risk of MSDs (Figure 2) was asked. The result indicated that the population interviewed considered that the factors most likely to increase the fact WRMSDs occur are repetitive movements have completed a percentage 92%, followed by organizational type conditions (such as lack of training for physiotherapy, massage, etc.) with a score of 87% and poor posture, also with 87%. Moreover, for the population surveyed, the least important factors were the psychosocial factors, work schedules and working patterns.

The result is that although the operators have indicated that biomechanical factors such as repetitive motions or poor posture can lead to increased risk, MMC (which also includes the lifting, transport and thrust loads) not figure in the most important according to the population surveyed, this factor being below factors such as financial rewards or lack of use of related techniques (solutions, legislation, etc.).

Figure 2. Factors that produce an increasing of WRMSDs according to interviewees.

In the next Question (P7), which is observed in the Figure 3, Operators were asked if they had experienced any musculoskeletal disorder related to work and for which they would be absent because of it (which covers from a few hours to several days, weeks or months). The data represented are calculated for a total of 15 cases were identified, of which six have been investigated and the rest, have been reported by workers during the interview.

The fine masonry (Group e) performs activities such as manual handling (which could be causing low back pain, repetitive movements or activities related to prepared walls that could be causing the tendinitis.

The lesions produced in networks duct (Group a): Correspond to low back pain, tendinitis and epicondylitis. Back pain could be related to the positions taken, like tendinitis and epicondylitis.

The activities of the group electricity networks (Group d): Countless repetitive movements occur, which is logical that some operators may be able to be suffering tendinitis related to repetitive movements they perform in their jobs.

In Group jobs machinery and piping (Group b): Have been reported back pain and neck contractures. A priori, it appears that low back pain and neck contractures (or even elsewhere in the body) may be produced by the activities comprising awkward postures, static postures, MMC, transport and thrust loads.

In group PCI pipe networks (Group c) quite the same that in the case of group with the peculiarity that have been registered as a disorder related to back pain.

Figure 3. Musculoskeletal disorders caused by work done by group.

In the question (P8) of the Figure 4, operators were asked about the time they were required to be absent from work due to the condition produced. The overall result obtained for all working groups, where also represents the difference between the disorders produced and required time off from work is displayed. Stresses again as back pain interestingly coinciding with the data records of accidents occurred. Back pain requires different periods of absence (less than 1 day, for 1 to 7 days and 1 to 4 weeks). Also appear as tendinitis. Data refer to the sample of n = 9 (who have responded have had any condition) and have not included the data from the job interview.

Notably, there have been no TME where operators had to leave more than a month from his job.

Figure 4. Time required to be absent from work due to any of musculoskeletal disorders produced during the work activity.

The cases in which respondents did not have to miss work (but the worker feels any musculoskeletal pain that may be related to their work) were questioned by the question (P9). The responses obtained show that the highest percentage is afflicted with the region of the lumbar spine.

In the Figure 5 relevant to the question (P10) to indicate the workers were asked how often they feel discomfort and does not include those cases in which it has had to be away from work. Results oriented region of the lumbar spine, as has been verified in previous sections were again obtained. The interesting facts are also reflected for the neck and shoulders.

Figure 5. Graphical representation of the timing for the inconvenience.

The Figure 6 is related to the Question (P11). The graphic represents duration of the painful episode.  It is noted that the lumbar spine resumed the transcendent level, despite the diversity in timing and this data is where you can get an orientation, since it is also the most repeated value in the above illustrations. Significantly, it does not occur in an environment of more than one month or one to four or five weeks. The highest percentage is in less than one day of course painful. Shoulder and neck, not the option of more than one month and one to four or five weeks is given. This type of pain therefore enrolled in a very short period and then repeat but referred routinely as seen in the above illustrations.

Finally, Question(P12) Figure 7 describes the sample of workers interviewed give a note of discomfort on a scale of 1-5 (as in the Borg scale), where you still get the highest score at the lumbar spine as expected.

Figure 6. Graphical representation of the duration of the episode.

Figure 7. Scale for grading inconvenience caused.

Discussion of results

Workers interviewed have indicated discomfort or pain confirm the occurrence of the processes that can lead to the development of diseases or work-related MSD's. The process as already described, is slow and progressive and begins insidiously in large cases.

Interestingly, the results obtained in the interview, pointing to the thoracolumbar region and neck-shoulder region as the areas that cause discomfort to workers. Although the discomfort a priori, might not seem important, it is a proven fact that the repetition of cases is representing long-term chronicity and diagnosis of an MSD [9].

Has been justified by the application of descriptive epidemiological studies why these painful processes and biomechanical factors related activities. Moreover, the results obtained in the questionnaire agree, for example, those obtained VII in the National Survey of 2011, which reflected that among workers in the construction sector, the lumbar region is the area most frequently suffer injuries and musculoskeletal disorders hazards [6].

Finally, it should be noted that the sample of respondents agreed that the biomechanical ergonomic factors is an important aspect in the production and development of MSDs.

Conclusions

Future lines leave open the case to understand the TME should be viewed from a bio-psychosocial perspective. Therefore, other factors are open to social, genetic, and psychosocial group, among others to corroborate the results. It would also be interesting to analyse gender issues in the sector.

Moreover, in future research it would be interesting to make a comparison of results using other methods of science or prestige, such as epidemiological analysis of cases and controls. Furthermore, cohort studies may provide more data to search for causal factors associated with certain groups of very specific work in the sector.

Moreover, they should conduct similar studies in parallel service sectors, in order to make a comparison of results.

Finally, some of the questions raised can be extended to a larger sample of workers, in order to perform a statistical analysis.

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