efek-ergonomi.pdf

Asia-Pacific Journal of Public HealthXX(X) 1 –17

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DOI: 10.1177/1010539511419199http://aph.sagepub.com

419199 APHXXX10.1177/1010539511419199Mahmud et alAsia-Pacific Journal of Public Health

1Program of Industrial Psychology and Organizational Psychology, Universiti Teknologi Malaysia, Malaysia2University of Sydney, Lidcombe, New South Wales, Australia3National Institutes of Occupational Safety and Health, Bangi, Malaysia

Corresponding Author:Norashikin Mahmud, Faculty of Management and Human Resource Development, Universiti Teknologi Malaysia, Johor, Bahru Campus, 81310 Skudai, Johor, Malaysia Email: [email protected]

The Effects of Office Ergonomic Training on Musculoskeletal Complaints, Sickness Absence, and Psychological Well-Being: A Cluster Randomized Control Trial

Norashikin Mahmud, PhD, MSc, BA1, Dianna T. Kenny, PhD, MA, BA (Hons)2, Raemy Md Zein, BSc3, and Siti Nurani Hassan, BSc3

Abstract

This study explored whether musculoskeletal complaints can be reduced by the provision of ergonomics education. A cluster randomized controlled trial study was conducted in which 3 units were randomized to intervention and received training and 3 units were given a leaflet. The effect of intervention on knowledge, workstation practices, musculoskeletal complaints, sickness absence, and psychological well-being were assessed at 6 and 12 months. Although there was no increment of knowledge among workers, significant improvements in worksta-tion practices in the use of monitor, keyboard, and chair were observed. There were significant reductions in neck and upper and lower back complaints among workers but these did not translate into fewer days lost from work. Workers’ stress was found to be significantly reduced across the studies. In conclusion, office ergonomics training can be beneficial in reducing mus-culoskeletal risks and stress among workers.

Keywords

cluster randomized controlled trial, office ergonomics training, injury prevention, computer user, musculoskeletal complaints, psychological well-being

Musculoskeletal complaints are commonly reported among office workers worldwide and these can have detrimental effects on workers’ health and productivity.1,2 Factors that predict risk of devel-oping musculoskeletal complaints can be divided into individual,3-5 ergonomic,6-9 and psychosocial

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2 Asia-Pacific Journal of Public Health XX(X)

factors.10-13 The risk of developing musculoskeletal complaints is higher among workers who have high work strain, longer mouse and keyboard use, perceived high muscle tension, previous musculoskeletal complaints in the neck and shoulder, as reported by several longitudinal studies with follow-up from 3 months to 5.4 years.14-19

Awareness and/or knowledge about the relationship between usage of computers and muscu-loskeletal complaints are essential to prevent them from becoming more severe. A study con-ducted in a French company reported that office and blue-collar workers had higher risk of sickness absence due to upper limb disorders compared with managers and professionals.20 It was also found in a population-based study in Sweden that respondents who reported concurrent low back pain and neck and shoulder disorders were at high risk for short-term and long-term sickness absence.21

In organizations, education/training is the best initial strategy in preventing occupational inju-ries.22,23 Training may also educate individuals from different managerial levels in the organiza-tion about office safety, which may simultaneously promote a culture of safety in the organization. Previous studies conducted on the effectiveness of office ergonomic training reported improve-ments in knowledge, workstation habits, and reduction in musculoskeletal disorders. One study used various educational interventions including posters, email, pictures on how to do stretching and stress relief activities, workshops, and informational booklets. These interventions were found to increase workers’ knowledge of cumulative trauma disorder and changes in the hand/wrist and neck/shoulder postures when using computers.24 The other study conducted on workers in a petrochemical research and development facility reported improvement in workstation con-figuration (mouse and head position) and symptom severity, but not in symptom reduction.25 Studies using different methods of ergonomics training have reported positive results. For exam-ple, those who received education programs such as participatory training (active learning ses-sion involving discussions and problem-solving exercises) and traditional training (lectures and handouts) reported less pain/discomfort and positive perception of psychosocial work stress than those who did not receive training.26 One study showed that both instructor-directed and self-directed learning were effective in bringing about positive changes in ergonomics knowledge and habits among workers.27 Another study, however, reported that training alone did not reduce musculoskeletal symptom growth among respondents when compared with combining training and adjustable chair as an intervention.28

The aim of the current study was to evaluate the effects of office ergonomics training compared with no training on musculoskeletal complaints and psychological well-being in university-based office workers. A cross-sectional survey had been previously conducted among the target group of Universiti Teknologi Malaysia (UTM) office workers that assessed their awareness of office ergo-nomics and prevalence of musculoskeletal complaints. The findings indicated a low level of office ergonomics awareness and high 12-month prevalence rates of musculoskeletal complaints in shoulder (51.6%), neck (48.2%), and back (42.2%) regions.29 Results from the study suggested that UTM staff were in need of office ergonomics training since they had not previously received any formal training. To our knowledge, we could not find any study on preventive measures of muscu-loskeletal disorders among computer users in Malaysia, hence the need for this study. However, we found only 2 articles on the prevalence and types of musculoskeletal disorders among office work-ers in Malaysia. A study conducted on clerical public servants reported 33% (95% confidence interval = 28.8-37.3) prevalence of upper limb symptoms.30 The other study, which was conducted among secretarial staff and undergraduate students, reported that poorer workstation ergonomics increased the risk of developing neck, back, and wrist disorders.31



Mahmud et al 3

Hypotheses

1. Office ergonomics training increases ergonomics knowledge.2. Office ergonomics training improves workstation habits.3. Office ergonomics training reduces musculoskeletal complaints among office workers.4. Office ergonomics training can improve psychological well-being.

MethodsStudy Design

Ethical approval to conduct the study was obtained from the University of Sydney Human Research Ethics Committee. This study was designed as a 2-armed cluster randomized con-trolled trial. The experimental groups received office ergonomic training, and the control groups were “business as usual” (no ergonomic training).

Participants and SettingOffice workers comprising staff from 6 units were invited to participate in the study. The inclu-sion criteria were those who were working with computers for at least 3 hours per day in either permanent or contract employment. Those who had any previous illness and/or injuries as a result of accidents and/or work hazards were excluded because these may have resulted in mus-culoskeletal disorders. We were only interested in musculoskeletal symptoms as a result of computer use. The majority of the office workers sat in a cubicle; the size of the cubicle was standardized, but it might have been smaller for several workstations because of space con-straints. Each staff member had his/her own designated desk equipped with monitor (traditional or flat screen), keyboard (traditional), and mouse (without wrist rest). The majority of workers working in a cubicle had a keyboard tray (without a mouse tray) attached to the desk. Some, but not all, workers not working in a cubicle had desks with a keyboard tray. In the case of workers with no keyboard tray, the keyboards were placed on the desk. Most staff had their own tele-phone; however, a small number shared a telephone with coworkers (1:2). Chairs and desks were adjustable, and staff had flexibility with respect to the movement of their keyboard and mouse. Workstation layouts were generally consistent across units. There had been no serious effort by management to upgrade these workstations ergonomically. Initial awareness of office ergonomics was very low.29

ProceduresTen units were identified, but only 6 units were included in the study. These 6 units were those who were willing to participate. Letters of invitation were sent out to the management of units to assign workers who were interested in participating in the study. A minimum number of 30 respondents from each unit were requested but more respondents were welcome as long as numbers did not exceeded 35 people because of the training room capacity. Three units were randomly assigned to the experimental group and 3 to the control group using a random number table. The random number was set as 6. The minimum value was set as 1 (experimental group) and maximum values as 2 (control group). The researchers were aware of the group allocation. Respondents were aware of the study but they did not know whether they belonged to the experimental or control group. Baseline questionnaires were distributed to respondents in the intervention and control groups before training took place. Each respondent had a unique ID that




can be identified by researchers only. Information from the baseline questionnaires assisted researchers in determining the right respondents according to the inclusion criteria and rejected those who fulfill the exclusion criteria. The intervention started in March 2009.

Respondents from the intervention groups received office ergonomics training. The in-house ergonomics training was conducted by trainers from the National Institute of Safety and Health (NIOSH). The training took place over a period of 1 day divided into 2 sessions and conducted by 2 trainers. The first session was conducted in the morning (9.00 am to 1.00 pm) and consisted of lectures on office ergonomics: understanding the relationship between office ergonomics and the development of musculoskeletal discomforts, ergonomics improvements and adjustments of workstations, and the importance of break and stretching exercises. The second session was conducted in the afternoon (2.00 pm to 4.30 pm) and focused on the practical aspects of the train-ing, in which trainers visited participants’ workstations and provided assistance on how to adjust workstations effectively. The same trainers who participated in the workstation observation at baseline conducted the observations; therefore, the interobserver bias was expected to be small. We encouraged respondents to stay at their workstation in order for the trainers to help them readjust their workstation if necessary. Trainers made suggestions on how to improve worksta-tion practices but these were restricted to workstation furniture, equipment, and space available. Respondents were also encouraged to participate in their workstation adjustments. Under some circumstances, further suggestions were made on how to adjust the workstation and/or space. The suggested changes would require support from management, for example, buying of new furniture and equipment or allocation of more space. Respondents from the control groups received a leaflet consisting of an office ergonomic diagram, tips on how to take a break, how to reduce their workload, and stretching exercises. The experimental group also received the same leaflet as the control group in addition to the ergonomic training.

Outcome MeasuresWe assessed outcomes at 6 and 12 months after training. The primary outcome measure was self-reported musculoskeletal complaints. Respondents were asked whether they had experi-enced any aches, pains, discomfort, or numbness in any part of the body regions at any time during the last 6 months as a result of working with a computer (yes or no). Data concerning the prevalence of musculoskeletal complaints were gathered using the modified Nordic Questionnaire.32 Musculoskeletal complaints was measured based on 9 categories: neck, right and left shoulder, upper and lower back, right and left upper limb (upper arm, elbow, lower arm, wrist, and fin-gers), and right and left lower limb (thigh/hip, knee, and feet). We combined right and left body region as 1 entity, for example, right and left shoulder, as shoulder for analysis.

Office ergonomics knowledge, workstation habits, psychological well-being, and sickness absence were the secondary outcome measures. Participants were asked about their office ergo-nomics knowledge in relation to the use of a monitor (eg, “I should place my monitor at arm’s length away from me”), mouse (eg, “The mouse can be placed at any position as long as I can reach it”), keyboard (eg, “The height of my keyboard should be at the same level as my elbow”), chair (eg, “I only need a backrest on my chair if I have back pain”), and desk (eg, “My desk height should be the same height as my elbow”). The questionnaire was developed by the researchers based on a comprehensive literature search and consisted of 28 items. Respondents selected from a 3-point scale that was coded as a binary variable: Agree = 1, Disagree = 0, and Don’t Know =0. The total scores for different areas of ergonomics knowledge were calculated.

A sample of respondents’ workstation ergonomics habits was randomly selected for observa-tion in each of the 6 departments/units at 2 weeks and 12 months follow-up. The observations were conducted by 4 people from the NIOSH. Trial observations were conducted prior to actual



Mahmud et al 5

observation of 2 office workers to make sure that trainers had a clear understanding of the work-station specification checklist and would use it reliably. The rating was either yes (if respondents had correct workstation habits) or no (incorrect workstation habits). The interrater reliability between the 4 observers was good (Cronbach α = .844). The checklist included items related to the use of monitor (5 items), keyboard (7 items), mouse (2 items), chair (7 items), and desk (2 items), for example, monitor is at arm’s length away from user, keyboard at the right height (elbow height), mouse is placed close to keyboard and within reach. The total scores for different areas of workstation ergonomics were calculated.

Psychological well-being was measured using the DASS-21 (Depression, Anxiety, and Stress) questionnaire.33 DASS-21 was chosen because of its ability to measure psychological distress in general34 and because of its frequent use in clinical and nonclinical settings.34-36 A translated and validated Bahasa Malaysia version was used to measure symptoms of depression, anxiety, and stress.37 DASS-21 was divided into 3 negative emotional states consisting of depres-sion (7 items), anxiety (7 items), and stress (7 items). The depression scale contains psychological symptoms such as devaluation of life, hopelessness, lack of interest, self-deprecation, anhedonia, dysphoria, and inertia. On the other hand, the anxiety scale measured skeletal musculature effects, autonomic arousal, subjective experience of anxious effect, and situational anxiety, whereas stress scales consisted of psychological symptoms, for example, easily upset, irritable or overreactive, difficult to relax, and nervous arousal. Respondents were asked to evaluate their feelings based on a 4-point scale (0 = Did not apply to me at all, 1 = Applied to me to some degree or some of the time, 2 = Applied to me a considerable degree, or a good part of the time, 3 = Applied to me very much, or most of the time). Since we are using DASS-21, the total score for each emotional symptom obtained is multiplied by 2. Higher scores indicate higher levels depression, anxiety, or stress. The mean score for the normative sample for depression is 6.34 ± 6.97, anxiety 4.70 ± 4.9, and stress 10.11 ± 7.9.

Sickness absence was assessed at baseline and postintervention by 2 items: “In the last 6 months, how many days (approx.) in total have you had off work due to work-related musculoskeletal com-plaints?” and “In the last 6 months, how many separate times have you had time off work due to work-related musculoskeletal complaints?” An average number of days and episodes of sickness absence were calculated.

Statistical AnalysesWe conducted intention-to-treat analysis in which respondents were considered exposed to the intervention assigned to them, that is, training and workstation adjustments. The between-group differences for office ergonomics knowledge and workstation habits were calculated from the differences of mean scores of correct answers and ergonomics habits in the monitor, keyboard, mouse, chair, and desk use; ANOVA test analysis was used to analyze the significant differences between groups. Analysis of repeated-measures ANOVAs was used to determine the effects of training on musculoskeletal complaints, sickness absence, and psychological well-being (DASS-21). Difference scores were used for analysis if there were significant differences at baseline.

ResultsBaseline Results for Demographic and Occupational Characteristics

The demographic and occupational characteristics of the study population at 6-month follow-up are presented in Table 1. The baseline characteristics between the 2 groups were essentially similar with respect to age, gender distribution, body mass index, and workplace characteristics.




Table 1. Demographics and Occupational Characteristics of Study Population at 6-Month Follow-up

Personal CharacteristicsTraining Group

(n = 43), Mean or %Control Group

(n = 55), Mean or %

Age 34.6 (10.4) 34.2 (8.4)Gender Male 30.2% 20% Female 69.8% 80%BMI (µ (SD; range)) Male 23.8 (3.0) 25.9 (5.8) Female 22.9 (4.7) 22.9 (3.6)Education High school (SRP/SPM) 58.1% 29.1% Technical certificate/diploma 23.3% 32.7% Degree (bachelor’s/post-degree) 9.3% 30.9% Other 9.3% 7.3%Hand use to operate computer Right 90.7% 92.7% Left 9.3% 7.3%Exercise per week No 30.2% 58.2% Yes 69.8% 41.8%Years of working using computer 10.4 (6.9) 11.2 (6.8)Hours sitting using computer 6.6 (1.6) 6.9 (1.4)Hours typing 5.1 (1.9) 5.2 (1.9)Days of sickness absence 0.26 (0.6) 0.78 (1.6)Episodes of sickness absence 0.26 (0.6) 0.58 (1.4)

Abbreviation: BMI, body mass index.

However, a greater number of respondents in the control group completed higher education and exercised less than the training group.

Response RateA total number of 89 respondents attended training and 69 (77.5%) returned baseline questionnaires. The response rate for 6 and 12 months were 58 (68.2% and 71.6%). There were 90 respondents in the control group with a response rate of 65 (72.2%) at baseline, 70 (77.8%) at 6 months, and 69 (77.5%) at 12 months. The number of dropouts because of resignation from UTM was 1.1% in the control group and 8.9% in the training group. Respondents who provided data at baseline and postintervention were included in the analyses. The total number of respondents included in the analysis was 42 for the training group and 50 the for no training group. The flow of the study is presented in Figure 1.

Office Ergonomics KnowledgeThe results show that there was only 1 significant difference in knowledge for either group over time. This occurred in the control group where knowledge about mouse use decreased over time (Table 2).



Mahmud et al 7

Assessed for eligibility (n=10 units)

Excluded(n = 4 units)

Randomized (6 units)

Received trainingUnit = 3 (89 participants)

Return questionnaires (n = 69)

No trainingUnit = 3 (90 participants)

Return questionnaires (n = 65)

Return questionnaires (n = 58)Maternity leave = 1

Resigned = 3Excluded because of

health problem = 1


Resigned = 1

Enrolment

Baseline

6 months


Resigned = 4Return questionnaires (n = 69)12 months

Figure 1. Study flow diagram

Table 2. Means (Standard Deviations) of Office Ergonomics Knowledge for Training and Control Groups at Baseline and 6 and 12 Months Follow-up

Training Group Control Group

Ergonomics knowledge Baseline 6 Months 12 Months P Value Baseline 6 Months 12 Months P Value

Monitor (n = 6) 1.8 (1.5) 1.9 (1.3) 1.9 (1.3) .901 1.6 (1.2) 1.4 (1.0) 1.2 (0.9) .165Keyboard (n = 10) 2.4 (2.0) 2.3 (1.5) 2.3 (1.4) .941 2.1 (1.5) 2.3 (1.7) 1.9 (1.3) .568Mouse (n = 5) 2.3 (1.3) 2.7 (0.9) 2.5 (1.1) .293 2.7 (0.9) 2.8 (0.9) 1.9 (1.2) <.0001Chair (n = 5) 1.3 (1.2) 1.5 (1.2) 1.7 (1.3) .349 1.5 (1.1) 1.3 (0.9) 1.3 (1.1) .445Desk (n = 2) 0.6 (0.8) 0.6 (0.8) 0.7 (0.7) .841 0.5 (0.7) 0.3 (0.6) 0.4 (0.7) .562

Workstation Habits

There were significant improvements in the use of monitor, keyboard, and chair among workers at 12-month follow-up (Table 3). The results from post hoc analysis showed the following: for




Table 3. Means (Standard Deviations) of Workstation Habits for Training and Control Groups at Baseline and 2 weeks and 12 Months Follow-up

Training Group Control Group

Workstation Ergonomics

Baseline (n = 30)

2 Weeks (n = 25)

12 Months (n = 27) P value

Baseline (n = 30)

2 Weeks (n = 23)

12 Months (n = 34) P Value

Monitor (n = 5) 3.3 (1.0) 3.8 (1.0) 4.3 (1.1) .002 2.6 (1.3) 2.7 (0.9) 2.6 (1.0) .826Keyboard (n = 7) 3.9 (2.2) 5.4 (1.6) 6.1 (1.2) <.0001 3.7 (1.9) 3.2 (1.5) 3.4 (1.9) .467Mouse (n = 2) 0.8 (0.8) 1.2 (0.8) 1.3 (2.1) .256 0.8 (0.7) 0.5 (0.6) 0.6 (0.7) .321Chair (n = 7) 3.8 (1.4) 5.7 (1.3) 5.5 (1.2) <.0001 3.9 (1.9) 3.9 (1.7) 3.7 (1.5) .867Desk (n = 2) 1.5 (0.6) 1.8 (0.4) 1.6 (0.7) .138 1.4 (0.6) 1.7 (0.4) 1.7 (0.5) .138

0

10

20

30

40

50

60

70

80

Nec

k Training No training

12months

6monthsBaseline

Figure 2. Percentage of neck complaints at baseline and 6 and 12 months follow-up (yes or no)

monitor, there was a significant improvement from baseline to 12 months (P = .002). For key-board and chair, there were significant improvements from baseline to 6 months (P = .002 and P < .0001, respectively) and from baseline to 12 months (P ≤ .0001 and P ≤ .0001, respectively). In contrast, there were no significant differences in the control groups at follow-up.

Self-Reported Musculoskeletal ComplaintsThere was a reduction of musculoskeletal complaints at 12 months for all body regions except for left upper limb regions. There were significant interactions between groups across time for neck (Figure 2), upper back (Figure 3), and lower back (Figure 4) complaints. There were sig-nificant main effects between groups for all body regions. The summaries of repeated-measures ANOVA are presented in Table 4. Respondents in the control group consistently reported an increase in discomfort in the neck, upper back, right and left upper limb, lower back, and right and left lower limb. The reported discomfort was consistent for left shoulder at all 3 times, and there was a smaller decrease in discomfort for right shoulder at 6 months. Overall, there were no significant differences of musculoskeletal discomforts over time in the control group.



Mahmud et al 9

0

10

20

30

40

50

60

Upp

er b

ack

Training No training

12months

6monthsBaseline

Figure 3. Percentage of upper back complaints at baseline and 6 and 12 months follow-up (yes or no)

0

10

20

30

40

50

60

Low

er b

ack

Training No training

12months

6monthsBaseline

Figure 4. Percentage of lower back complaints at baseline and 6 and 12 months follow-up (yes or no)

Number of Days and Episodes of Sickness Absence

There were no significant interactions between groups over time for the number of days and episodes of sickness absence in the training and control groups (Table 5 and Figures 5 and 6).

Psychological Well-Being (DASS-21)Repeated-measures 1-way ANOVA revealed a significant decrease in depression, anxiety, and stress symptoms in the training group (Table 6). The means of the depression and anxiety scales were more significantly reduced after the training when compared with before the training (Figures 7 and 8). The mean for the stress scale decreased at 6 months and remained lower at 12



10

Tabl

e 4.

Rep

eate

d-M

easu

res A

naly

ses

of V

aria

nce

for

Self-

Rep

orte

d M

uscu

losk

elet

al C

ompl

aint

s

Mus

culo

skel

etal

C

ompl

aint

s

With

in-S

ubje

cts

Effe

cts

Betw

een-

Subj

ects

Effe

cts

Inte

ract

ion

Effe

cts

Mai

n T

ime

Effe

ctM

ain

Gro

up E

ffect

Con

tras

t A

naly

ses

Gro

up *

Tim

e Ef

fect

Nec

kF(

1.90

0) =

2.4

04 (

P =

.096

)F

= 22

.882

(P

≤ .0

001)

CG

> T

G (

P ≤

.000

1)F

= 5.

289

(P =

.024

)R

ight

sho

ulde

rF(

1.90

3) =

2.3

02 (

P =

.106

)F

= 9.

228

(P =

.003

)C

G >

TG

(P

= .0

03)

F =

1.93

6 (P

= .1

68)

Left

sho

ulde

rF(

2) =

0.0

97 (

P =

.907

)F

= 6.

040

(P =

.016

)C

G >

TG

(P

= .0

16)

F =

.411

(P

= .5

23)

Upp

er b

ack

F(2)

= 0

.565

(P

= .5

69)

F =

5.93

4 (P

= .0

17)

CG

> T

G (

P =

.017

)F

= 4.

956

(P =

.028

)R

ight

upp

er li

mb

F(2)

= 1

.225

(P

= .2

96)

F =

9.42

5 (P

= .0

03)

CG

> T

G (

P =

.003

)F

= 2.

366

(P =

.127

)Le

ft u

pper

lim

bF(

2) =

1.3

16 (

P =

.271

)F

= 13

.467

(P

= <.

0001

)C

G >

TG

(P

≤ .0

001)

F =

1.20

2 (P

= .2

76)

Low

er b

ack

F(2)

= 1

.120

(P

= .3

29)

F =

8.63

8 (P

= .0

04)

CG

> T

G (

P =

.004

)F

= 5.

563

(P =

.021

)R

ight

low

er li

mb

F(2)

= 1

.489

(P

= .2

28)

F =

6.59

0 (P

= .0

12)

CG

> T

G (

P =

.012

)F

= 2.

422

(P =

.123

)Le

ft lo

wer

lim

bF(

2) =

1.8

67 (

P =

.158

)F

= 8.

069

(P =

.006

)C

G >

TG

(P

= .0

06)

F =

1.61

8 (P

= .2

07)

Abb

revi

atio

ns: C

G, c

ontr

ol g

roup

; TG

, tra

inin

g gr

oup.



Mahmud et al 11

Table 5. Results of Repeated-Measures Analyses of Variance for the Number of Days and Episodes of Sickness Absence Using Difference Scores

Sickness Absence

Within-Subjects EffectsBetween-Subjects

Effects Interaction Effects

Main Time Effect Main Group Effect Group * Time Effect

Number of days of sickness absence

F(1.161) = 0.039 (P = .876) F = 1.162 (P = .284) F = 0.001 (P = .978)

Episodes of sickness absence

F(2) = 0.020 (P = .981) F = 0.326 (P = .569) F = 1.813 (P = .182)

12months

6monthsBaseline

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Day

s of

sic

knes

s ab

senc

e

Training

No training

Figure 5. Means for days of sickness absence at baseline and 6 and 12 months follow-up

12months

6monthsBaseline

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Epis

odes

of s

ickn

ess

abse

nce

Training

No training

Figure 6. Means for episodes of sickness absence at baseline and 6 and 12 months follow-up




Table 6. Results of Repeated-Measures Analyses of Variance for Depression, Anxiety, and Stress (DASS-21)

DASS-12

Within-Subjects EffectsBetween-Subjects

Effects Interaction Effects

Main Time Effect Contrast Analyses Main Group Effect Group * Time Effect

Depression F(1.921) = 8.043 (P = .001)

T1 > T2 (P = .003); T1 > T3 (P = .001)

F = 0.065 (P = .800)

F = 2.119 (P = .149)

Anxiety F(2) = 5.024 (P = .008)

T1 > T2 (P = .021); T1 > T3 (P = .004)

F = 0.190 (P = .664)

F = 2.943 (P = .090)

Stress F(2) = 12.859 (P ≤ .0001)

T1 > T2 (P ≤ .0001); T1 > T3 (P ≤ .0001)

F = 0.007 (P = .935)

F = 8.783 (P = .004)

Abbreviations: DASS-12, Depression Anxiety Stress Scales–12; T1, baseline; T2, 6-month follow-up; T3, 12-month follow-up.

12months

6monthsBaseline

0

1

2

3

4

5

6

7

8

Dep

ress

ion

Training

No training

Figure 7. Means for depression at baseline and 6 and 12 months follow-upThe maximum possible score for depression is 42 and higher score indicates more symptom severity.

12months

6monthsBaseline

0

2

4

6

8

10

Anx

iety Training

No training

Figure 8. Means for anxiety at baseline and 6 and 12 months follow-upThe maximum possible score for anxiety is 42 and higher score indicates more symptom severity.



Mahmud et al 13

months after training (Figure 9). A significant interaction across time periods was found for the stress scale (P = .004).

DiscussionOffice ergonomics training as the primary injury prevention program has beneficial effects on workstation practices, lower musculoskeletal risks, and reduced stress among computer users. Although there was no significant improvement in knowledge over time among respondents who received training, training did have an impact on behavioral changes. We observed improvements in workstations habits with respect to how workers used their monitor, keyboard, and chair. The largest improvements were in the position of monitor and keyboard; workers’ body posture in elbow, forearms, upper arms, wrists, and shoulders when typing; and workers’ body posture for lumbar support, thighs, knees, and feet while sitting. These findings are sup-ported by other studies showing that training improves computing body postures and worksta-tion ergonomics practices.27,38-40 Our study showed that the training session, the help and guidance given by trainers, and the active participation of workers in their workstation adjust-ments were effective in improving workstation ergonomics practices.

The improvement in workstation habits benefited workers in terms of having good computing body postures and techniques for using computers, which may lower the risk of future musculo-skeletal disorders. There was a significant reduction of complaints in the neck and upper and lower back among workers in training group over time. The results indicate that training in the correct interaction with one’s workstation may have significant benefits to workers in terms of their musculoskeletal well-being. Evidence-based accessible guidelines and appropriate training should be available to all workers. Previous studies have reported that training alone was less effective in reducing musculoskeletal complaints if workers were not provided with appropriate equipment to implement their new ergonomic knowledge. Two studies, one combining training and adjustable chairs28 and the other combining training with a flexible workstation41 reported lower musculoskeletal disorders among workers compared with those who received training and flexible workspace only. This study was limited in that it was unable to include the quality of the work environment or to provide more ergonomically appropriate workstations to participants.

12months

6monthsBaseline

0

2

4

6

8

10

12

Stre

ss Training

No training

Figure 9. Means for stress at baseline and 6 and 12 months follow-upThe maximum possible score for stress is 42 and higher score indicates more symptom severity.




Nonetheless, this study has shown that improvements in musculoskeletal complaints can be achieved with a simple, cost-effective training program.

The positive impact of the workstation adjustment and the reduction of musculoskeletal com-plaints could be explained with reference to the health behavior model commonly used in health education and health promotion.42 This model suggests that behavioral change is determined by an individual’s perception of the disease and the difficulty of the strategies needed to decrease it.43 According to this model, the perceived health threat would direct the individual toward healthy behavioral change. For example, respondents who attended the office ergonomics training were given information regarding the association between office ergonomics and the risk of having musculoskeletal complaints and the intervention strategies to reduce them. As a result, they would be able to identify the threat and/or be made aware of the seriousness of the symptoms if they remained untreated. The individual’s willingness and ability to change his or her health habits based on the interventions may influence willingness to change health behaviors and maintain the changed behavior. However, this would only take place if the respondents realized the benefit to health of behavioral change. Although barriers to behavioral change were not assessed, it is likely that they would affect the change process as outlined in the model. In addition, the influence from the external and internal factors may also influence the success of behavioral change, for example, advice from others, mass media campaigns, and one’s own belief (self-efficacy) as to whether one can make the changes,44 may also influence the success of the intervention. Future studies need to look deeper into the contribution of these factors to provide more informa-tion on the effectiveness of education health program on health.

There were no significant differences in sickness absence in the training group when com-pared with the control group. We could not comment on the lack of significant findings because we only measured reduction in complaints’ frequency (yes vs no). Further exploration is needed as to why reduced musculoskeletal complaints in visual display unit operators did not result in fewer days lost from work. Nevertheless, workers in the training group reported reduced symp-toms of stress across time compared with the control group. The majority of workers in the train-ing group reported normal level of stress symptoms, and the mean was above the normative sample at baseline; the levels of improvement after intervention were not clinically significant. Despite this fact, the findings concurred with those of Bohr,26 who reported that ergonomics training reduces psychosocial work stress among those who receive participatory education. Bohr was not sure whether the improvement in the work area configuration or worker postures resulted in the decrease of psychosocial work stress, although earlier studies conducted on the association between stress and work-related musculoskeletal disorders demonstrated an associa-tion.45,46 The causal relationship between both is still unclear in the epidemiological field.47 Therefore, more studies are needed to explore the causal relationship between musculoskeletal disorders and occupational stress.

LimitationsSample size calculation was not conducted because of the conduct of the study in a naturalistic setting. Thus, we could not determine study statistical power with respect to the mean value differences between 2 clusters. The number of respondents who were included in the analysis was small because we only included those who had the same ID. We did not measure the sever-ity and duration of pain as one of the primary outcome measures. Contamination between indi-viduals from the same clusters may influence the effect of outcomes. In addition, transfer of knowledge between clusters might have occurred during social interactions and/or during atten-dance at courses since workers were from the same geographical area but in different locations (ie, buildings). The sample size was not large enough to adjust for the effect of possible



Mahmud et al 15

confounders. The strength of our study was the randomization of groups to intervention and control groups, which is the most efficient way to control for the effects of known and unknown confounders. Although blinding of respondents is desirable in randomized controlled trials to reduce potential responder and observer biases, it is often not achievable in field-based studies such as the study reported here.

ConclusionsWe reported on a preliminary study to determine the effectiveness of office ergonomics training to reduce musculoskeletal complaints in UTM. We found that office ergonomics training improved workstation habits, reduced musculoskeletal complaints, and reduced psychological well-being among office workers but the impact was small. We hope that the results may ben-efit UTM staff as the management is made aware that inexpensive ergonomics training has a positive impact on the safety and health of office workers. University management can actively participate in both training and investment in adjustable furniture for office workers. Further research combining training and use of adjustable furniture in UTM is recommended in the future.

Acknowledgments

The authors thank each participating unit/department that participated in the study and also Associate Professor Dr Maketab bin Mohamed, the Director of Occupational Health and Safety Unit, Universiti Teknologi Malaysia, who supported our study. We also would like to thank trainers from NIOSH who conducted workstation observations. We also thank Dr Robert Heard and Dr Roger Adams, Sydney University, for helpful comments on the statistical analyses.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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