The impact of ergonomic-educational interventions on reduction of musculoskeletal symptoms among employees of oil and gas installations in Iran

Abstract

BACKGROUND:

Musculoskeletal disorders can cause increased absenteeism, costs, and injuries.

OBJECTIVE:

The present study was aimed to investigate the impact of ergonomic-educational interventions on the reduction of musculoskeletal symptoms among employees of oil and gas installations.

METHODS:

This interventional study was conducted on 1243 male workers of oil and gas installations in the south of Iran. The Nordic questionnaire and quick exposure check (QEC) method were used to evaluate the risk of developing musculoskeletal disorders in the participants. Then, the educational interventions via training sessions, designed educational booklets and leaflets, and prepared educational film were performed. Data were collected at the times of two months before and six months after the interventions.

RESULTS:

The prevalence of musculoskeletal symptoms, at least in one of the body areas, was equal to 71.28%. The results showed that the prevalence of these symptoms significantly decreased in all body areas after the educational interventions (P <0.028). The highest reduction rate occurred in the regions of wrists and hands (52.77%), knees (47.17%), and waist (47.13%), respectively. Moreover, the results indicated that the mean value of the total score of quick exposure check (QEC) had a meaningful decrease from 0.92 to 0.54 after the educational interventions (P <0.0001).

CONCLUSION:

The planned educational interventions efficiently reduced the prevalence of musculoskeletal symptoms and the ergonomic risk levels estimated by QEC in the research population.

Keywords

Musculoskeletal symptoms Nordic questionnaire QEC method ergonomics educational intervention oil and gas industries

1 Introduction

Occupational musculoskeletal disorders, as a group of injuries and disabilities, result in increased absenteeism and costs in developed and developing countries [1]. The National Institute for Occupational Safety and Health (NIOSH) has categorized the diseases caused by work based on their importance (in terms of prevalence, intensity, and prevention possibility). The second rank after occupational respiratory diseases belongs to the musculoskeletal disorders [2]. Studies have shown that these disorders are very costly, and backaches have the first rank in terms of prevalence [1 , 4]. The prevalence of musculoskeletal diseases in workplaces is directly related to ergonomic conditions so that some factors such as repetitive movements, improper postures, and load carrying increase their prevalence [5, 6]. Based on the results of the conducted studies, the cause of nearly half of the absenteeism in the workplaces is musculoskeletal disorders [7].

Oil and gas industries directly and inevitably involve the workers in the process of production. Physical activities, such as manual materials handling, are abundantly seen in these industries, and improper working postures are very common. In such conditions, it is expectable that musculoskeletal diseases are created with high prevalence in different body areas of the employees. There are various solutions to control these risk factors. One of the easiest, quickest, and most effective interventions to reduce the prevalence of musculoskeletal disorders is education, which should receive special attention along with other control measures. Without it, the results of other interventions might not be effective. Results of some studies show that educational programs can prevent and reduce musculoskeletal problems at the workplace [8, 9]. Operating activities, especially in the oil and gas industries, are important jobs with the high prevalence of musculoskeletal symptoms, which require preventive interventions. Given the incremental development of oil and gas installations and the high prevalence of musculoskeletal disorders in these industries, the implementation of preventive measures in different groups such as administrative and operating personnel is essential [10]. Therefore, the present study was aimed to determine the prevalence of musculoskeletal symptoms, evaluate the ergonomic risks of these disorders, and investigate the impact of ergonomic-educational interventions on the reduction of musculoskeletal symptoms among the employees of oil and gas installations in the south of Iran.

2 Methods

This interventional study (quasi-experimental) was conducted from November 2018 to June 2019. Data were collected at the times of two months before and six months after the educational interventions.

In this study, 1568 male workers were selected using a blinding chart, among which 1243 subjects met the inclusion criteria. All steps of the study were in accordance with the ethical code IR.TUMS.VCR.REC.1398.558. All participants confirmed consciously the consent form provided by the committee. The participants were working in administrative, service, operative, dril-ling, and maintenance sectors of oil and gas installations in the south of Iran. In the administrative sector, the subjects were performing the tasks such as working with computers and writing with the tools of the desk, chair, keyboard, and mouse. The frequency of the repetitive activities such as typing were more than ten times at minutes and the time duration of the static activities such as prolonged sitting was higher than two hours. In service sectors, the workers were carrying out the tasks such as cleaning and sweeping up with the tools of the broom, dustpan, and rags. The frequency of the repetitive activities such as cleaning and sweeping up were more than ten times at minutes and the time duration of these activities was higher than four hours. In the operative section, the persons were doing the tasks such as checking, sampling, and monitoring with the tools of gage, valve, and lever. The frequency of the repetitive activities such as stair going up and down, walking, and valve opening and closing were more than ten times at minutes and the time duration of the static activities such as prolonged standing was higher than two hours. In the drilling sector, workers were accomplishing the tasks such as checking, sampling, and monitoring with the tools of gage, valve, and wrench. The frequency of the repetitive activities such as stairs climbing, valves opening and closing, and wrenching were more than ten times at minutes and the time duration of the static activities such as prolonged sitting and standing was higher than four hours. In the maintenance sector, the subjects were performing the tasks such as welding, cutting, and mechanical repairing with the tools of welding machine, cutting torch, and wrench. The frequency of the repetitive activities such as stairs climbing, valves opening, and closing, and wrenching were more than ten times at minutes and the time duration of the static activities such as prolonged sitting and standing, welding, and cutting was higher than four hours. Inclusion criteria were no history of other diseases affecting the musculoskeletal system, no history of accidents resulting in musculoskeletal injuries, no history of participation in ergonomic courses over the past year, and no history of work experience in other industries. Moreover, literate workers were selected because of the use of educational booklets, as one of the educational materials in the study.

At first, the participants presented self-evaluation of their job to safety and health officers. Then, the researchers explained the reasons for conducting the study to the subjects and assured them that their personal information is confidential and will not be accessible to any other individuals or organizations. In the next step, two researchers asked the participants to fill out the questionnaires for 30 minutes during rest periods between the working shifts.

2.1 Persian version of the Nordic standard questionnaire

The Persian version of the Nordic questionnaire translated by Namnik et al. was used to evaluate the musculoskeletal symptoms in the different body areas of workers [11]. The results of a study performed by Namnik et al. showed that the Persian version of the Nordic questionnaire is a reliable and valid tool to assess work-related musculoskeletal disorders (WMSDs) in Iranian industrial workers [11, 12]. The questionnaire is available in the Appendix A.

2.2 Exposure assessment of workers to risk factors

The Quick Exposure Check (QEC) method was used to evaluate the exposure level of the workers to risk factors of musculoskeletal disorders [13, 14]. This method can quickly assess the exposure to a wide range of risk factors of musculoskeletal disorders in static and dynamic works using a hypothetical scoreboard. The total score is ranged from 46 to 269 and can be categorized into four categories, including low (46–84 points), moderate (106–138 points), high (168–198 points), and very high risk (187–242 points) [14].

2.3 Interventions

Ergonomic-educational interventions were presented as follows:

Four one-hour training sessions were held by instructional video and PowerPoint presentation on the risk factors of musculoskeletal disorders, prevention methods of them, proper layout of equipment at workplace, proper conditions of working, and correct use of tools. Education was conducted by five instructors who were trained by the designer.

Educational films were prepared and distribu-ted among workers to be aware of the ergono-mics principles, musculoskeletal disorders, and ergonomic conditions at the workplace.

Educational booklets and leaflets were distributed among workers. Those were designed based on the attitudes, intention, and perceived behavioral control and regarding the observed physical postures. This booklet was used to increase the awareness of the worker on proper body postures, ergonomic risk factors, common musculoskeletal diseases, ergonomic working stations, and physical work capacity.

After that, the instructors helped the participants to readjust their workstations if needed. In the end, a series of tailored educational messages were sent by email based on the observational evaluations in the times of one, three, and five months after the interventions.

2.4 Assessment after interventions

The musculoskeletal symptoms and risk factors were re-evaluated after six months by the Persian version of the Nordic standard questionnaire and QEC method, respectively, and the effectiveness of the interventions was investigated. Figure 1 illustrates the trend of the intervention procedure in this study.

Fig. 1

The trend of intervention procedure in the survey.

2.5 Data analysis

Data were analyzed using SPSS (Ver. 19) software at a significance level of 0.05. Since the Kolmogorov-Smirnov test showed that the data had no normal distributions, non-parametric statistical tests, such as Mann–Whitney U test, X², Sign test, and McNamara’s test, were used for the data analysis. Mann–Whitney U test was used to investigate the difference between two independent groups. X² test was applied to evaluate the homogeneity of the variables. The Sign test was used to determine the impact of the interventions on reducing the ergonomic risk level estimated by the QEC method. McNemar’s test was also applied to study the effects of the interventions on decreasing the prevalence of musculoskeletal symptoms in all body areas of the participants.

3 Results

In this study, 886 subjects (71.28 %) had musculoskeletal symptoms at least in one of the body areas and 357 ones (28.72 %) were without those. Table 1 shows the frequency distribution of the participants based on the job sections. The highest prevalence of musculoskeletal symptoms (88.92 %) was related to the workers of the maintenance sector. Also, Table 2 represents demographic parameters in the two groups with and without the musculoskeletal symptoms. Results of Mann–Whitney U test showed that mean values of age, work experience, and body mass index were significantly different between two groups with and without musculoskeletal symptoms (P <0.001). However, it was shown that the difference in weight and height parameters between the two groups were not statistically significant. Based on the results of the X² test, 40.8 % of the subjects were smokers and 59.2 % of them were not. The prevalence of musculoskeletal symptoms significantly was higher in smoker workers compared with non-smokers ones before the interventions (P <0.0001).

Table 1
Frequency distribution of participants based on the job sections

Job section All participants People with musculoskeletal symptoms People without musculoskeletal symptoms

Number Percentage Number Percentage Number Percentage

Administrative sector 187 100 88 47.06 99 52.94

Service sector 124 100 60 48.39 64 51.61

Operative sector 280 100 199 71.07 81 28.93

Drilling sector 273 100 202 73.99 71 26.01

Maintenance sector 379 100 337 88.92 42 11.08

Total 1243 100 886 71.28 357 28.72

Job section	All participants	People with musculoskeletal symptoms	People without musculoskeletal symptoms
Administrative sector	187	100	88	47.06	99	52.94
Service sector	124	100	60	48.39	64	51.61
Operative sector	280	100	199	71.07	81	28.93
Drilling sector	273	100	202	73.99	71	26.01
Maintenance sector	379	100	337	88.92	42	11.08
Total	1243	100	886	71.28	357	28.72

Table 2

Demographic parameters in two groups with and without musculoskeletal symptoms

Parameter	All participants		People with musculoskeletal symptoms		People without musculoskeletal symptoms		P value
	Mean	Standard deviation	Mean	Standard deviation	Mean	Standard deviation
Age (Year)	29.07	4.8	35.1	3.2	26.2	3.9	<0.0001
Work experience (Year)	10.13	4.3	17.8	3.1	10.4	2.3	<0.0001
Weight (Kg)	75.8	6.03	79.8	6.5	80.5	7.1	0.078
Height (m)	1.74	0.06	1.73	0.09	1.80	0.08	0.068
Body mass index (Kg/m²)	25.04	3.51	26.66	3.45	24.85	4.12	<0.0001

Table 3 presents the number of body regions affected before and after the interventions. Based on the results, the subjects with one (71.28 %) and two (66.85 %) body regions affected had the highest relative frequencies before the intervention, respectively. However, the greatest reduction rate in the prevalence of musculoskeletal symptoms occurred in the persons with eight (54.01 %) and nine (52.47 %) body regions affected, respectively.

Table 3

The number of body regions affected before and after interventions

The number of body regions affected	Before interventions	After interventions	Reduction rate (%)
	Number	Percentage	Number	Percentage
1	886	71.28	491	39.50	44.58
2	831	66.85	447	35.96	46.21
3	713	57.36	413	33.23	42.07
4	525	42.24	327	28.72	32.01
5	439	35.32	271	21.80	38.28
6	387	31.13	204	16.41	47.29
7	294	23.65	165	13.27	43.89
8	237	19.07	109	8.77	54.01
9	103	8.29	49	3.94	52.47

Table 4 reports the prevalence of musculoskeletal symptoms in various body areas of workers before and after the interventions. Results of McNemar’s test showed that the prevalence of musculoskeletal symptoms significantly decreased in all body areas of the workers after the interventions (P <0.028). The highest reduction rate occurred in the regions of wrists and hands (52.77), knees (47.17 %), and waist (47.13 %), respectively. The results showed that the mean value of the total score of quick exposure check (QEC) had a meaningful decrease from 0.92 to 0.54 after the educational interventions (P <0.0001). Table 5 indicates the results of the evaluations performed by the QEC method before and after the interventions. Based on the results, the ergonomic risk level with a value of four had the highest relative frequency before the interventions (36.77 %) while the greatest relative frequency was related to the ergonomic risk level with the value of one (76.75 %) after the interventions. Results of the Sign test determined that the ergonomic risk level estimated by the QEC method significantly decreased after the interventions (P >0.0001). Moreover, Table 6 represents the frequency distribution of effective risk factors in producing musculoskeletal disorders in the studied subjects before and after the interventions. Based on the results, awkward posture in various body regions had the greatest relative frequency among the risk factors before the interventions. Also, the highest reduction rates were related to the risk factors of awkward posture and load lifting and handling after the interventions. However, the relative frequencies of the risk factors of vibration, high work pace, and high stress were not significantly different before and after the interventions.

Table 4

Prevalence of musculoskeletal symptoms in various body areas of workers before and after interventions (n = 1243)

Region of body	Having musculoskeletal symptoms				Reduction rate (%)	P value
	Before interventions		After interventions
	Number	Percentage	Number	Percentage
Waist	868	69.83	459	36.92	47.13	0.003
Wrists/Hands	758	60.98	358	28.80	52.77	0.002
Elbows	783	62.99	422	33.95	46.10	0.002
Shoulders	623	50.12	361	29.04	42.06	0.003
Neck	757	60.90	418	33.62	44.79	0.003
Back	727	58.48	437	35.15	39.89	0.023
Hips/thighs	524	42.16	291	23.41	44.47	0.009
Knees	812	65.32	429	34.51	47.17	0.026
Feet/Ankles	415	33.38	236	18.98	43.14	0.004

Table 5

Results of evaluation performed by QEC method before and after interventions (n = 1243)

Total QEC score	Ergonomic risk level	Exposure level to musculoskeletal risk factors	Before interventions		After interventions
			Number of workers	Percentage	Number of workers	Percentage
Less than 40 %	1	Acceptable	158	12.71	954	76.75
41 % to 50 %	2	More investigations are required.	269	21.64	156	12.56
51 % to 70 %	3	More investigations are required and ergonomic corrective measures need to be applied soon.	359	28.88	84	6.75
More than 70 %	4	More investigations are required and ergonomic corrective measures need to be applied immediately.	457	36.77	49	3.94
Total			1243	100.0	1243	100.0

P <0.0001.

Table 6

Frequency distribution of effective risk factors in producing musculoskeletal disorders in the studied subjects before and after interventions

Risk factor	Before interventions		After interventions		Reduction rate (%)	P value
	Number	Percentage	Number	Percentage
Awkward postures of waist	923	74.26	416	33.47	54.93	0.002
Awkward posture of wrists/hands	907	72.97	521	41.91	42.56	0.003
Awkward posture of shoulders/arms	815	65.57	362	29.12	55.59	0.001
Awkward posture of neck	764	61.46	359	28.88	53.01	0.005
Repetitive movement	826	66.45	617	49.64	25.30	0.032
Load lifting and handling	498	40.06	274	21.96	45.18	0.008
Vibration	89	7.16	78	6.28	12.29	0.084
High work pace	312	25.10	284	22.85	8.96	0.123
High stress	459	36.93	407	32.71	11.43	0.097

4 Discussion

In the present study, the prevalence of musculoskeletal symptoms among the workers of oil and gas installations in Iran was equal to 71.28 %. Hassanvand et al. investigated the prevalence of musculoskeletal disorders among the staff of an oil refinery and reported that 69.8 % of the subjects had at least one of these disorders in the last 12 months [15]. The results of a study performed by Aabo Salem et al. showed that 47.7 % of the workers in the natural gas fields had regional musculoskeletal pains [16]. Kalteh et al. also concluded that the prevalence of musculoskeletal disorders among employees of offshore oil and gas installations was high, which can be due to inappropriate working conditions such as repetitive work, loads lifting, and limited rest periods [10]. Also, the results of the present study indicated that the highest prevalence of musculoskeletal symptoms was related to the workers of the maintenance sector. In the study of Morken et al., maintenance workers had the highest relative frequency of musculoskeletal symptoms in Norway’s offshore petroleum industry [17]. This occupational group requires repetitive work, high physical workload, load lifting, walking on hard surfaces, and stair and ladder climbing, which can be the causes of this high prevalence.

Based on the results of the present study, the mean values of age, work experience, and body mass index in the subjects with musculoskeletal symptoms compared to the persons without those were significantly higher. It may be because the body’s tolerance to external pressures decreases with increasing age. Also, the accumulation of musculoskeletal disorders occurs in individuals with more work experience. Moreover, load pressure increases on the back and knees with the increment of weight and body mass index (BMI) and causes pains in these regions. Ekpenyong and Inyang founded that the odds of work-related musculoskeletal disorders escalate with increasing age and body mass index in construction workers [18]. The results of a study conducted by Oho et al. showed that older age can make a higher prevalence of musculoskeletal pains among computer users [19]. Also, in the present study, it was determined that the prevalence of musculoskeletal symptoms was higher in smoker workers compared to non-smokers. Palmer et al. also conducted a study on 12907 people in the UK and concluded that there was a correlation between smoking and musculoskeletal disorders [20].

The results of this study indicated that the subjects with one and two body regions affected had the greatest relative frequencies before the intervention, respectively. The symptoms are firstly created in a low number of body regions. Then, these symptoms are spread and appear in different parts of the body during the time. However, the highest reduction rate in the prevalence of musculoskeletal symptoms occurred in the persons with eight and nine body regions affected, respectively. It may be because some symptoms were improved and some of those remained after the interventions. This is caused that the relative frequency of the subjects with a low number of regions affected increases and the relative frequency of the persons with a high number of affected regions decreases.

In this study, the highest values of the prevalence of musculoskeletal symptoms were related to the regions of waist and knee and the lowest prevalence was related to the region of hips/thighs. Oluka et al. also studied the prevalence of work-related musculoskeletal symptoms among domestic gas workers and resulted that the lower-back and shoulder were the most body parts affected, and the hips/thighs had the least prevalence [21]. Hassanvand et al. concluded that the most common musculoskeletal disorder was in the lumbar area among the workers of an oil refinery [15]. Moreover, Kalte et al. observed that the highest rates of pain occurred in the areas of knees and back among the workers of offshore oil and gas installations [10]. The results of the present study are consistent with those of other studies. Extensive walking on hard surfaces, frequent stair climbing, high-frequency manual loading and carrying, and prolonged standing are some important causes to produce pain in the regions of the waist and knee of workers of oil and gas industries [22].

The results of the present study demonstrated that the educational interventions were effective in reducing the prevalence of musculoskeletal symptoms of all body areas among the workers of oil and gas installations. The highest reduction rate occurred in the regions of wrists and hands, knees, and waist, respectively. Therefore, the planned educational interventions with contents of ergonomics principles, risk factors, prevention methods, and ergonomics designs through oral training sessions, educational films, booklets and leaflets, and corrective recommendations were efficient. Appropriate postures, desirable designs, work and rest periods, exercises, correct methods of load lifting and carrying, and proper use of tools and equipment were seriously considered in this training. Also, people were encouraged to play an active role in the ergonomic interventions after the training. Indeed, these educational courses were caused that people understand the benefits of their new behavior, and actively participate in ergonomics interventions [23]. Perhaps, for this reason, the greatest reduction rates in the relative frequencies were observed in the regions of wrists and hands, knees, and waist. Of course, the results determined that the interventions significantly decreased the prevalence of musculoskeletal symptoms in all body areas. In the study of Karimian et al. on 216 nurses, it was shown that the disorders in the areas of the lower back, shoulder, neck, and wrist were significantly reduced after eight weeks of education [24]. Furthermore, Vyas proved that educational interventions on musculoskeletal disorders through audio-visual aids and printed literature could increase the knowledge of the farmworkers and help to reduce the risk of many musculoskeletal problems [25]. Motamedzadeh et al. also showed that implementation of an educational intervention designed based on the risk factors of hazardous jobs could decrease the signs and symptoms of musculoskeletal disorders in workers of a television manufacturing industry [26]. Yektayi et al. investigated the effect of education on the reduction of musculoskeletal disorders, and it was observed that education including training sessions, educational film, and booklets significantly reduced the incidence of musculoskeletal disorders [27]. The findings of the current study are consistent with those of the stated studies. Moreover, the results of the present study revealed that the ergonomic risk level estimated by the QEC method significantly decreased after the interventions. Based on the results, the ergonomic risk level with the value of four had the highest relative frequency before the interventions while the greatest relative frequency was related to the ergonomic risk level with the value of one after the interventions. In the study of Laal et al. also, the score of the QEC method significantly decreased after educational interventions in tailors [28]. Of risk factors evaluated by the QEC method, awkward posture in various body regions had the greatest relative frequency before the interventions. Also, the highest reduction rates after the interventions were related to the risk factors of awkward posture and load lifting and handling. The results of a study performed by Bazazan et al. showed that the intervention based on posture correction can decrease musculoskeletal symptoms and fatigue among control room operators [29]. Besides, Bulduk et al. concluded that ergonomic education could reduce the exposure to risk factors of work-related musculoskeletal in the workplace of sewing machine operators [30]. Robertson et al. showed that office ergonomic training in the workplace significantly improved the perceived control, posture, and workstation conditions [31]. Therefore, the planned educational program in the present study could correct the posture and reduce risky behaviors of the workers using different tools. However, this interventional program was not effective in controlling the risk factors of vibration, high work pace, and high stress. This can be because the prevention of these risk factors requires administrative and organizational measures while the target population of this study was the workers. These results show the importance of macro-ergonomics and implementation of educational programs in all levels of an organization, which should be considered in the next studies.

5 Limitations

As one of the limitations in this study, all participants were male and the effect of the educational interventions was not studied on the female workers. Another limitation included a lack of face-to-face training for each person because of the large number of samples. However, in the present study, it was tried to reduce the number of participants in each training session. Moreover, there was a likelihood of self-report bias because of the use of the Nordic questionnaire. Also, the clinical and possibly electroneurographic examination was not conducted for the diagnosis of musculoskeletal disorders. For this reason, the QEC method was applied to evaluate the risk of developing musculoskeletal disorders in addition to the questionnaire.

6 Conclusions

In total, the results of this study indicated that the prevalence of musculoskeletal symptoms was high among people working in one of the gas and oil industries, particularly in the body areas of the waist, knee, and lowest. Based on the results, the planned educational interventions with the forms of training sessions, educational film, and booklets to stabilize information in the minds were effective in reducing the prevalence of musculoskeletal symptoms of all body areas. Therefore, this educational program can be used to decrease musculoskeletal symptoms in industries. It could correct the posture and reduce the risky behaviors of the workers but could not control some risk factors such as vibration, work pace, and stress. This shows the need to macro-ergonomics interventions for preventing these factors.

Footnotes

Acknowledgments

The authors would like to thank all participants of this study.

Conflict of interest

The authors declare that they have no conflict of interest.

Appendix: Questionnaire used in the study

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