Relation between psychosomatic disturbances and job stress in video display unit operators

Abstract

BACKGROUND:

Some psychosomatic disturbances have been related to protracted video display unit (VDU) use at work, and they may be associated with job stress.

OBJECTIVE:

This study aimed at assessing the association between psychosomatic disturbances with job-related and subjective stress in 990 VDU.

METHODS:

Job stress was evaluated by Karasek’s Questionnaire, psychological job demands and job decision latitude scores were calculated. Workers were assigned to four categories: high-strain job, low-strain job, active job, and passive job. Subjective perception of stress was evaluated with the Rapid Stress Assessment Scale.

RESULTS:

None of the psychosomatic disturbances investigated were associated with higher psychological job demands scores, whereas many of them were significantly related to lower job decision latitude scores and high-strain jobs. All psychosomatic disturbances were significantly associated with personal stress. Logistic regression confirms the protective role of job decision latitude on headache, fatigue, intestinal gas, disturbed sleep and the significant role of subjective stress on all psychosomatic disturbances studied.

CONCLUSIONS:

Whereas subjective stress is harmful, job decision latitude is a protective factor for several psychosomatic disturbances reported by VDU operators. Improvement in the job decision latitude might be a preventive specific measure in work planning to reduce possible stress-related disorders.

Keywords

Job demands job decision latitude employee Karasek’s Job Content Questionnaire

1 Introduction

Over the last few decades, computers have revolutionized many people’s lives and jobs. A new profession, the video display unit (VDU) operator, has emerged and consequently many physical and psychological problems have appeared [1 –4].

Lundberg [5] outlined stress as “the imbalance between perceived demands from the environment and the individual’s perceived resources to meet those demands.” Many employees work in stressful situations and are exposed to different stressors [6 –8]. When the requests/demands exceed a worker’s capacity to fulfill them, the working context becomes stressful, increasing the risk of psychosomatic disturbances [9–10].

A relationship between VDU work and some psychosomatic and neuro-vegetative disturbances has been demonstrated in some studies [11 –13]. These problems, if ignored, can prove debilitating and cause crippling injuries, forcing one to change one’s job [14, 15].

Computers, a hallmark of technological advancement have ushered in a new genre of occupational health problems. In a sample of 25,000 workers, VDU work for more than five h/day was found to be associated with an increased rate of subjective physical and psychological symptoms, e.g., joint pain, headache, fatigue, anxiety, depression, eye fatigue and disturbed sleep [15]. In another study, VDU work for more than six h/day was associated with disturbed sleep [12].

Work-related stress can be caused by some different factors such as work content, organization and environment, poor communication and so on [16, 17].

By the European framework directive 89/391 on health and safety, all employers have a legal obligation to protect the occupational safety and health of workers even as regards problems of work-related stress. This concept is successively developed in the European framework agreement on work-related stress [18]. Stressful working conditions can also impact employees’ well-being indirectly by directly contributing to negative health behavior or by limiting an individual’s ability to make positive changes to lifestyle behavior [19].

The European Agency for Safety & Health at Work, through a survey of UE workers, has classified stress as the second cause of work-related problems. Besides, stress can be the cause of an average number of 4 days of absence from the workplace, which makes a total number of 600 million working days lost every year in the EU.

The development of psychosomatic disturbances seen in VDU operators [20] may be related to job stress. Protracted VDU work is considered as a significant source of psychophysical job strain [21]. Stress acts on the perception of fatigue [22], it may induce gastric disturbances by affecting the gastrointestinal tract via activation of the autonomic nervous system [23] and has a powerful influence on headache [23, 24] and sleep regulation mechanisms [25].

However, in literature, no studies analyzed the relationship between the presence of psychosomatic disturbances and job stress rather than the subjective perception of stress disorders in VDU operators.

The present study was carried out with the objective of studying computer-related psychosomatic disturbances in a sample of VDU operators and the role of subjective perception of stress.

2 Research method

2.1 Sample population

A total of 1,543 VDU operators, chosen through a random selection process, completed an anonymous self-report questionnaire in 2013–2015. All VDU workers were employed in public offices and had the opportunity to manage their breaks autonomously.

The questionnaire required information regarding the 12 previous months. It was administered only after a little training on how to fill it in, to increase the accuracy of answers.

The study was performed as part of the periodic occupational health surveillance, and it required no formal approval by the local Ethics Committee, which was nevertheless consulted and which granted an informal authorization. Participants were informed about the study aims and procedures and gave their written informed consent to participate.

Exclusion criteria were: chronic migraine, use of medications, systemic diseases, exposure to chemicals in hobbies or extra-job activities, PC use≥30 min/day in leisure time.

Furthermore, other exclusion criteria were: working at a VDU workstation that did not comply with standard guidelines for workstations [26]; the presence of binocular visual acuity disturbances that did not allow an 8/10 capacity, even after use of corrective lenses.

These exclusion criteria have been inserted to reduce, as already shown in other studies, the confounding factors due to poor sight correction and/or nonergonomic workstations [27].

2.2 Measures

Job stress was assessed with the psychological job demands and job decision latitude scores of Karasek’s Job Content Questionnaire (JCQ) [28]. Dichotomized categories of decision latitude (low and high) and psychological job demands (low and high), based on the median value of the sample, have commonly been used to create quadrants of job strain: high-strain job (high job demands and low decision latitude), low-strain job (low job demands and high decision latitude), active job (high job demands and high decision latitude) and passive job (low job demands and low decision latitude).

The level of subjective perception of stress was evaluated with the Rapid Stress Assessment (RSA) Scale [29] a multiple choice self-assessment rating scale with 15 items and 4 possible answers ranging from “not at all” to “much,” rated from 0 to 3. The total stress score was obtained by adding all item scores and ranged from 0 to 45 points. The test proved to be reliable and valid [29].

Each VDU operator went through a complete medical check-up, with sight measurement.

2.3 Socio-demographic variables

In the last part of the questionnaire, participants provided information about the usual socio-demographic characteristics, such as gender (a dummy variable, 1 = male and 2 = female); age and job seniority. Stress assessment in the workplace has been focused on its environmental, psychological and biological aspects: ergonomics aspects, lightness, continuous sitting position (work is carried out continuously, sitting on a chair without getting up for≥4 h/day), habits and protracted use of any type of alcohol, smoking, coffee and energy drinks (for at least 12 months). Psychosomatic disturbances analyzed were: disturbed sleep, headache, fatigue, gastric pain, intestinal gas, and poor digestion. Respondents were asked how often they had the symptoms in the last month; their frequency was evaluated on a 4-point scale as 0 = never, 1 = occasionally (1-2 times/month), 2 = often (1 time/week) and 3 = very often (≥2 times/week). Categories 0-1 and 2-3 were subsequently grouped in binary variables.

2.4 Data analyses

Statistical data analysis was based on a calculation of means, standard deviation (SD), and frequencies, according to the nature of every single variable. Differences between the means were compared by using Student’s t-test for unpaired data. Frequencies of the single variables were compared by using the chi-square test (χ²) with Yates’s correction and Fischer’s exact test. The data analyses were conducted using SPSS version 20 for Windows. All tests were two-sided with a significance level of 5%. The phi-coefficient analysis was used to analyze the associations between the various psychosomatic disturbances expressed in binary mode. Spearman’s rho test was used to study the correlations between psychological job demands (JD), job decision latitude (JDL) and subjective stress scores.

The χ² test (dichotomous variables) or the one-way ANOVA and Bonferroni’s post-hoc test (continuous variables) were used to test the association of each psychosomatic disturbance with demographic, job and stress parameters and JCQ job categories (high-strain job, low-strain job, active and passive job) against subjective stress. Multiple logistic regressions were then applied considering each psychosomatic disturbance in binary mode, age, and sex as confounding factors, and stress parameters as single independent variables.

3 Results

A total of 553 (36%) subjects were excluded as they fell within the sample exclusion criteria, namely: 117 (21%), their workstations did not comply with standard guidelines; 51 (9%), suffer from systemic pathologies; 385 (70%) had no properly lens-corrected acuity disturbances (binocular visus < 8/10).

990 (64%) subjects were included in the survey: 544 females (55%) and 446 males (45%). Mean age was 47.7±9.4 years, 19% were smokers and mean job seniority was 13.5±6.7 years

From the questionnaire data, it was observed that the average hours spent seating at the workstation were 5.3±2.1 hrs daily; continuous sitting was reported by 36%.

Results collected with the questionnaire are summarized in Table 1.

Table 1
Data of the 990 participants collected with the questionnaire

Demographic and job Sex (f/m) 55% /45% *

characteristics Age (years, mean±sd) 47.7±9.4

Smokers 19%

Job seniority (years, mean±sd) 13.5±6.7

Daily hours of vdu use (hours, mean±sd) 5.3±2.1

Continuous sitting position 36%

Stress Psychological job demands (score, mean±sd) 32.9±3.7 (range 12–48)

Job decision latitude (score, mean±sd) 65.3±11.6 (range 24–96)

JCQ categories

High-strain job 20%

Low-strain job 21%

Active job 31%

Passive job 28%

Subjective stress (RSA score, mean±sd) 14.4±5.8 (range 0–45)

Psychosomatic Headache 9%

disturbances Fatigue 21%

Gastric pain 12%

Intestinal gas 14%

Poor digestion 10%

Disturbed sleep 31%

*p < 0.001 vs men; Chi-square test.

As regards the JCQ, the mean psychological job demands score was 32.9±3.7 (range 12–48) and the mean job decision latitude score was 65.3±11.6 (range 24–96). Overall, 20% (n = 198) of subjects were involved in a high-strain job and 21% (n = 208) in a low-strain job; 31% (n = 307) did an active job and 28% (n = 267) a passive one. The mean RSA score was 14.4±5.8 (range 0–45).

Headache was reported by 9% (n = 89); fatigue by 21% (n = 208); gastric pain by 12% (n = 120); intestinal gas by 14% (n = 139); poor digestion by 10% (n = 99), and disturbed sleep by 31% (n = 307).

All psychosomatic disturbances were significantly associated (p < 0.001) with each other (see Table 2). JCQ scores were significantly (p < 0.01) correlated with subjective stress, in particular, the subjective stress correlated positively with the psychological job demands score and negatively with the job decision latitude score (see Table 3).

Table 2

Phi-coefficient analysis of associations between the psychosomatic disturbances

	Headache	Fatigue	Gastric pain	Intestinal gas	Poor digestion	Disturbed sleep
Headache	1	0.288*	0.266*	0.215*	0.218*	0.143*
Fatigue	0.288*	1	0.277*	0.322*	0.263*	0.171*
Gastric pain	0.266*	0.277*	1	0.447*	0.594*	0.163*
Intestinal gas	0.215*	0.322*	0.447*	1	0.498*	0.148*
Poor digestion	0.218*	0.263*	0.594*	0.498*	1	0.111*
Disturbed sleep	0.143*	0.171*	0.163*	0.148*	0.111*	1

*p < 0.001; Phi correlation coefficient analysis.

Table 3

Correlations between the psychological job demands, the job decision latitude and the subjective stress

	Subjective stress	Psychological job demands	Job decision latititude
Subjective stress	1	0.110*	–0.229*
Psychological job demands	0.110*	1	0.237*
Job decision latitude	–0.229*	0.237*	1

*p < 0.01; Spearman’s rho coefficient.

Testing of the JCQ against the subjective perception of stress scores showed that high-strain jobs were characterized by a significantly higher mean subjective perception stress score compared to low-strain jobs (16.4±6.2 vs. 12.3±5.3; p < 0.001) and to active jobs (16.4±6.2 vs. 13.5±5.1; p < 0.001), and that passive jobs were associated with a significantly higher mean subjective perception stress score compared with low-strain jobs (14.8±5.4 vs. 12.3±5.3; p < 0.001).

Age was associated with intestinal gas and disturbed sleep. Female sex was associated with all psychosomatic disturbances except gastric pain. Smoking was associated with gastric pain and intestinal gas. Job seniority was associated with gastric pain and poor digestion; daily VDU use with a headache and gastric pain; continuous sitting with fatigue and gastric pain. All disturbances were associated to less job decision latitude scores except gastric pain; they were significantly more prevalent among the workers involved in high-strain jobs; moreover, they were significantly associated with a higher subjective stress score (see Table 4).

Table 4

Distribution of demographic, job and stress parameters on psychosomatic disturbances

	Headache		Fatigue		Gastric pain		Intestinal gas		Poor digestion		Disturbed sleep
	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No
Age (years, mean±SD)	46.9±7.7	47.4±9.3	48.1±8.1	47.2±9.3	48.8±8.1	47.2±9.2	49.1±7.3*	47.0±9.4	49.1±7.9	47.2±9.2	48.8±8.0**	46.7±9.5
Sex (F/M, %)	13/4***	87/96	24/17**	76/83	13/10	87/90	23/9***	78/91	11/7*	89/92	36/27**	64/73
Smoker (yes/no, %)	10/11	90/89	20/27	80/73	19/13*	81/87	82/19***	72/28	15/11	85/89	29/29	71/71
Job seniority (years, mean±SD)	13.8±7.6	13.5±6.6	14.4±6.8	13.3±6.6	15.2±7.8**	13.3±6.5	14.4±6.8	13.4±6.6	15.1±7.6*	13.3±6.5	13.5±6.5	13.4±6.6
Daily VDU use (hours, mean±SD)	6.1±3.9***	5.2±1.8	5.5±1.9	5.2±2.1	6.0±3.6***	5.1±1.8	5.5±1.6	5.2±2.2	5.4±1.7	5.2±2.1	5.4±2.6	5.1±1.8
Continuous sitting (yes/no, %)	13/10	87/90	34/29*	67/77	18/13*	82/88	24/19	76/82	14/11	86/89	30/29	71/71
Psychological job demands (score, mean±SD)	33.3±3.5	32.8±3.7	33.3±3.7	32.7±3.7	33.5±4.2	32.7±3.6	32.7±3.8	32.9±3.7	33.4±3.1	32.8±3.8	33.3±3.6	32.7±3.8
Job decision latitude (score, mean±SD)	60.2±11.5***	65.8±11.6	61.8±12.3***	66.5±11.2	64.4±12.6	65.4±11.5	61.1±11.5***	66.3±11.4	62.2±11.8**	65.6±11.6	62.4±11.3***	66.4±11.7
JCQ categories
High-strain (%)	17⁺⁺	83	38⁺⁺⁺	62	20⁺	80	31⁺⁺⁺	69	19⁺⁺	81	41⁺⁺⁺	60
Low-strain (%)	5⁺	95	15⁺⁺⁺	85	9	91	13⁺	87	8⁺	92	20⁺⁺	80
Active (%)	7⁺	93	21	79	16	84	13⁺⁺	87	11	89	25	75
Passive (%)	14	86	29	71	11	89	25⁺	75	10	90	30	70
Subjective stress (RSA score, mean±SD)	18.5±6.1***	14.0±5.7	19.0±5.7***	13.2±5.2	18.1±6.2***	13.9±5.6	17.8±5.9***	13.7±5.6	17.9±5.7***	14.0±5.7	17.7±5.8***	12.9±5.2

Yes = often/very often; No = not at all/occasionally. *p < 0.05; **p < 0.01; ***p < 0.001 yes vs no. ⁺p < 0.05; ⁺⁺p < 0.01; ⁺⁺⁺p < 0.001 vs all subjects of other JCQ categories. Chi-square test (dichotomous variables); one-way ANOVA and Bonferroni’s post-hoc test (continuous variables).

Logistic multivariate analysis, adjusted for age and sex, confirmed the protective role of job decision latitude on headache, fatigue, intestinal gas and disturbed sleep. Moreover, all psychosomatic disturbances were associated with subjective stress (see Table 5).

Table 5

Logistic regression of the presence each psychosomatic disturbance with job decision latitude score and subjective stress score, adjusted for age and sex. Bold text indicates significant OR

	Headache		Fatigue		Gastric pain		Intestinal gas		Poor digestion		Disturbed sleep
	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI
Job decision	0.97	0.95–0.99	0.97	0.95–0.99	0.99	0.98–1.02	0.98	0.96–0.99	0.98	0.96–1.01	0.98	0.96–0.99
latitude
Subjective	1.14	1.09–1.19	1.27	1.22–1.33	1.13	1.09–1.18	1.13	1.09–1.17	1.12	1.07–1.16	1.15	1.12–1.19
stress

OR = Odds Ratio; 95% CI = 95% confidence interval.

4 Discussion

Work involving VDU is widespread in modern society with a remarkable increase in the last several decades [27, 30].

Computerized jobs are often boring since they require cognitive processing and mental attention on monotonous data series and usually do not require too much muscular energy. Instead, they require spending long hours in a seated posture with mind oriented to little stimulating intellectual work, often with repetitive topics it is not possible to escape from. Sometimes, the production demands of these jobs are high, with constant work pressure and little decision making possibilities and heavy daily computer work often causes stress conditions [3, 4].

Various disturbances are related to VDU work. With the spread of this type of work and the associated appearance of health complaints in workers, a vast amount of research has aimed at identifying the possible causes of the health problems associated with VDU work [31 –33].

Along with the rapid changes of working environments into VDT stations, various symptoms related to VDT use have been reported but only on musculoskeletal, ocular systems or stress conditions due to postural, microenvironmental bad conditions and humdrum of the work.

Relations have often been found between physical disturbances and factors such as improper work organization and job design or with psychological factors in a broad sense; nothing has yet been observed as to psychosomatic symptoms such as headache, gastric pain, intestinal disorders, poor digestion and/or insomnia.

This study analyzes for the first time the association between stress (from the job and/or personal source) and psychosomatic disturbances in VDU operators.

It has to be said that work stress can produce both physical and emotional complaints [22 –25].

Job demands -physical and psychological- influence the severity and frequency of health complaints in VDT operators. The expression of these complaints may be worsened by perceived high job demands, boring or repetitive job activity and poor support from colleagues and supervisors.

Our investigation was conducted on a selected population of subjects with superimposable environmental working conditions and work duties. All the subjects had no oculovisual abnormalities. This selection was made to reduce or exclude the presence of disturbances resulting from refractive conditions of the subject. Under these conditions, the study showed clearly that data from JCQ correlated significantly with subjective stress, subjective stress correlated positively with the psychological job demands score.

Tomei et al. observed, on a group of VDU operators and drivers/rescuers, an association between stress and the field of job demand that included: workload, work organization and environment [34]. Aasa et al. observed an association between job demand and sleeping problems, headache and stomach symptoms in ambulance personnel known to be subject to strong emotional stress [35].

In this study, lower job decision latitude scores were significantly associated with headache, fatigue, intestinal gas, poor digestion, and disturbed sleep; these associations were confirmed by adjusting data for sex and age except for poor digestion. Logistic multivariate analysis also confirmed the association between all psychosomatic disturbance and subjective stress.

Unfortunately, no comparison can be made with other studies, as job stress-related disturbances have been dealt with and are not those subjectively reported.

The impact of job stress on health has been extensively studied since the publication of Karasek’s model in 1981 [36]. High workload, increased work pressure and low job control was related to high daily life stress in VDT (video display terminal) operators [37, 38]. Marcus and Gerr [39] showed that increased psychosocial strain, increased reporting of job stress and lack of social support were all related to an increase of clinical symptoms. However, it is important not to forget the old knowledge concerning basic human needs that must be satisfied to create social environments and primarily healthy work [40, 41].

The limitations to the present study were the non-consideration of 36% of employees who fell within the sample’s exclusion criteria, with consequent loss of information coming from these employees. Therefore, it will be necessary to widen up the study by considering these workers too, as well as confounding factors like poor sight correction and/or non ergonomic workstations

Moreover, the lack of other studies like this still does not allow to compare the results obtained.

5 Conclusions

The psychosomatic disturbances are probably more related to individual character and subjective ways of dealing with stress than the mere presence of job stress. Suitable mechanisms to cope with general stress may help to not somatize job stress [11, 42]. However, results of different stress questionnaires can be interrelated [43, 44] as confirmed by this study, in fact, the two measures of stress are interdependent, i.e., job stress arises more efficiently in a subject who is already experiencing subjective stress. Since subjective stress is not predictable, an improvement in the job decision latitude might be a preventive specific measure in work planning to reduce possible stress-related disorders in VDU operators.

Conflict of interest

All authors have no conflicts of interest to declare.

References

Seguí

MDM

, Cabrero-García

, Crespo

, Verdú

, Ronda

. A reliable and valid questionnaire was developed to measure computer vision syndrome at the workplace. J Clin Epidemiol. 2015;68:662–73.

Lyu

, Wu

, Duan

, Xiang

. The effects of forearm support on upper body for people in front of monitor: A meta-analysis. Archiv Environ Occup Health. 2015;70:243–50.

Tomei

, Ciarrocca

, De Sio

, Suppi

, Sinibaldi

, Di Pastena

, Scala

, Corbosiero

, De Angelis

, Prenna

, Tomei

, Sancini

. Stress and information-communication technologies: From videoterminal to web. Clin Ter. 2012;163.

Kowalska

, Bugajska

. Health problems among computer workers. Med Pr. 2009;60:321–5.

Lundberg

. Psychophysiology of work: Stress, gender, endocrine response, and work-related upper extremity disorders. Am J Ind Med. 2002;41:383–92.

Bergomi

, Modenese

, Ferretti

, Ferrari

, Licitra

, Vivoli

, et al. Work-related stress and role of personality in a sample of Italian bus drivers. Work. 2017;57(3):433–40.

Elgmark Andersson

, Larsen

, Ramstrand

. A modified Job Demand, Control, Support model for active duty police. Work. 2017;58(3):361–70.

Kinnunen-Amoroso

, Liira

. Work-related stress management between workplace and occupational health care. Work. 2016;54(3):507–15.

Tomei

, Rosati

, Martini

, Tarsitani

, Biondi

, Pancheri

, Monti

, Ciarrocca

, Capozzella

, Tomei

. Assessment of subjective stress in video display terminal workers. Ind Health. 2006;44:291–5.

10.

Norder

, van der Ben

, Roelen

, Heymans

, van der Klink

, Bültmann

. Beyond return to work from sickness absence due to mental disorders: 5-year longitudinal study of employment status among production workers. Eur J Public Health. 2017;27(1):79–83.

11.

Arnetz

, Zhdanova

, Arnetz

. Patient involvement: A new source of stress in health care work? Health Commun. 2016;31(12):1566–72.

12.

Soriano

, Kozusznik

, Peiró

, Mateo

. Mediating role of job satisfaction, affective well-being, and health in the relationship between indoor environment and absenteeism: Work patterns matter! Work. 2018;61(2):313–25.

13.

Specchiale

, Attinà

, De Maria

, Sapienza

IAM

, Sarra Fiore

, Nicotra

, Massimino

, Petralia

, Ramaci

. Pilot Study On The Role of Psychosocial Aggression in a sample of Cops and Robbers. Acta Medica Mediterranea. 2013;29:407–10.

14.

Yoshioka

, Saijo

, Fukui

, Kawaharada

, Kishi

. Association between duration of daily visual display terminal work and insomnia among local government clerks in japan. Am J Ind Med. 2008;51:148–56.

15.

Nakazawa

, Okubo

, Suwazono

, Kobayashi

, Komine

, Kato

, Nogawa

. Association between duration of daily VDT use and subjective symptoms. Am J Ind Med. 2002;42:421–6.

16.

Bourbonnais

, Brisson

, Vinet

, Vézina

, Abdous

, Gaudet

. Effectiveness of a participative intervention on psychosocial work factors to prevent mental health problems in a hospital setting. Occup Environ Med. 2006;63:335–42.

17.

Mikkélsen

, Saksvik

. Impact of a participatory organizational intervention on job characteristics and job stress. Int J Health Serv. 1999;29:871–93.

18.

ETUC, European Resource Centre: http://resourcecentre.etuc.org/.

19.

Chrousos

. Stress and disorders of the stress system. Nat Rev Endocrionol. 2009;5:374–81.

20.

Balci

, Aghazadeh

. The effect of work-rest schedules and type of task on the discomfort and performance of VDT users. Ergonomics. 2003;46:455–65.

21.

Rantanen

. Challenges for occupational health from work in the information society. Am J Ind Med. 1999;36:1–6.

22.

Suwazono

, Dochi

, Kobayashi

, Oishi

, Okubo

, Tanaka

, Sakata

. Benchmark duration of work hours for development of fatigue symptoms in japanese workers with adjustment for job-related stress. Risk Anal. 2008;28:1689–98.

23.

Shima

, Satoh

. Somatoform disorders in the workplace in japan. Int Rev Psychiatry. 2006;18:35–40.

24.

Malkki

. Migraine: Long screen time exposure could increase the risk of migraine. Nat Rev Neurol. 2016;12(1):4.

25.

Yokoyama

, Yokoyama

, Funazu

, Yamashita

, Kondo

, Hosoai

, Yokoyama

, Nakamura

. Associations between headache and stress, alcohol drinking, exercise, sleep, and comorbid health conditions in a japanese population. J Headache Pain. 2009;10:177–85.

26.

OSHA, Occupational Safety and Health Act: www.osha.gov/dcsp/osp/index.html.

27.

Eltayeb

, Staal

, Hassan

, De Bie

. Work related risk factors for neck, shoulder and arms complaints: A cohort study among dutch computer office workers. J Occup Rehabil. 2009;19:315–22.

28.

Karasek

, Brisson

, Kawakami

, Houtman

, Bongers

, Amick

. The job content questionnaire (JCQ): An instrument for internationally comparative assessments of psychosocial job characteristics. J Occup Health Psychol. 1998;3:322–55.

29.

Tarsitani

, Biondi

. Sviluppo e validazione della scala VRS (Valutazione Rapida dello Stress). Medicina Psicosomatica. 1999;44:163–77.

30.

Grudin

. Three Faces of Human-Computer Interaction. IEEE Annals of the History of Computing. 2005;27:46–62.

31.

Bergqvist

, Knave

. Eye discomfort and work with visual display terminals. Scand J Work Environ Health. 1994;20:27–33.

32.

Thomson

. Eye problems and visual display terminals - the facts and the fallacies. Ophthalmic Physiol Opt. 1998;18:111–9.

33.

Aarås

, Horgen

, Bjørset

H-

, Ro

, Thoresen

. Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions. Appl Ergon. 1998;29:335–54.

34.

Tomei

, Soria Pascual

, Mosca Angelucci

. Analysing performance of real textile wastewater bio-decolourization under different reaction environments. J. Clean. Prod. 2016;129:468–77.

35.

Aasa

, Brulin

, Ängquist

K-

, Barnekow-Bergkvist

. Work-related psychosocial factors, worry about work conditions and health complaints among female and male ambulance personnel. Scand J Caring Sci. 2005;19:251–8.

36.

Nomura

, Nakao

, Sato

, Ishikawa

, Yano

. The association of the reporting of somatic symptoms with job stress and active coping among japanese white-collar workers. J Occup Health. 2007;49:370–5.

37.

Smith

. Psychosocial aspects of working with video display terminals (VDTs) and employee physical and mental health. Ergonomics. 1997;40:1002–15.

38.

Conway

. Psychological mood state, psychosocial aspects of work, and musculoskeletal discomfort in intensive video display terminal (VDT) work. Int J Hum -Comput Interact. 1999;11:95–107.

39.

Marcus

, Gerr

. Upper extremity musculoskeletal symptoms among female office workers: Associations with video display terminal use and occupational psychosocial stressors. Am J Ind Med. 1996;29:161–70.

40.

Ramaci

, Pellerone

, Ledda

, Rapisarda

. Health promotion, psychological distress, and disease prevention in the workplace: A cross-sectional study of italian adults. Risk Manage Healthc Policy. 2017;10:167–175.

41.

Ledda

, Cicciù

, Puglisi

, Ramaci

, Nunnari

, Rapisarda

. Attitude of health care workers (HCWs) toward patients affected by HIV/AIDS and drug users: A cross-sectional study. Int J Environ Res Public Health. 2017;14(3).

42.

Holt

, Clark

, Kreuter

, Rubio

. Spiritual health locus of control and breast cancer beliefs among urban African American women. Health Psychology. 2003;22:294–299.

43.

Rassolian

, Peterson

, Fang

, Knight

, Peabody

, Baxley

, Mainous

. Workplace factors associated with burnout of family physicians. JAMA Intern Med. 2017;177(7):1036–8.

44.

Amati

, Tomasetti

, Ciuccarelli

, Mariotti

, Tarquini

, Bracci

, Baldassari

, Balducci

, Alleva

, Borghi

, Mocchegiani

, Copertaro

, Santarelli

. Relationship of job satisfaction, psychological distress and stress-related biological parameters among healthy nurses: A longitudinal study. J Occup Health. 2010;52:31–8.

Demographic and job	Sex (f/m)	55% /45% *
characteristics	Age (years, mean±sd)	47.7±9.4
	Smokers	19%
	Job seniority (years, mean±sd)	13.5±6.7
	Daily hours of vdu use (hours, mean±sd)	5.3±2.1
	Continuous sitting position	36%
Stress	Psychological job demands (score, mean±sd)	32.9±3.7 (range 12–48)
	Job decision latitude (score, mean±sd)	65.3±11.6 (range 24–96)
	JCQ categories
	High-strain job	20%
	Low-strain job	21%
	Active job	31%
	Passive job	28%
	Subjective stress (RSA score, mean±sd)	14.4±5.8 (range 0–45)
Psychosomatic	Headache	9%
disturbances	Fatigue	21%
	Gastric pain	12%
	Intestinal gas	14%
	Poor digestion	10%
	Disturbed sleep	31%