Introduction

Health is a multidimensional concept, which is why the definition of the World Health Organization (WHO) for health covers three physical, mental, and social dimensions (1, 2). Health promotion is a fundamental human need (1). The protection and promotion of health in occupational environments is a major task of managers and planners. In this regard, ergonomics is one of the most important sciences and can significantly help managers and planners to achieve health-related objectives. From an ergonomic point of view, the most critical factor involved in occupational accidents and injuries is the inconsistency between the workload, and abilities and limitations of people (3).

From a cognitive perspective, mental health is a variable of how people perceive and interpret the world, in* particular, their surrounding environment (4). Studies have shown that physical and mental health can be affected by job-related factors (5). High workload, time restriction, and environmental stresses can severely affect the mental health of an individual (6). From an ergonomic perspective, there should be a balance between the workload and abilities of an individual, for an imbalance in this regard can give rise to stressors (7).

Human health can be compromised as a result of stress, leading to an imbalance in physical and mental status. Long-term exposure to work-related stresses is one of the underlying causes of burnout (8). Stress is a physical, psychological, or social force that when applied to a system, can stimulate some significant changes. Lazarus and Folkman see stress as a special relationship between an individual and the environment, which is perceived as a sort of threat or demand which is beyond their ability and resources, and therefore, threatens their comfort and convenience (6). The role of stressful environments in creating the symptoms of depression is well-recognized; stressful life events can predict most depression symptoms (9). In today’s world, one of the most crucial sources of stress is occupation (9). Occupational stress is a mental and emotional response motivated by imbalance between work demands and the abilities of an individual (10).

Occupational stress is an underlying factor in mental disorders, especially depression (11). The work life of each individual is characterized by various stressors that exert significant psychological pressure on their mind. Work-related developments such as organizational changes, salary change, promotions, layoffs and recruitments, and social transformation are among the factors that expose people to pressures of all kinds, casing anxiety, confusion, concern, and stress.

Occupational stress is of paramount importance in psychology; it was introduced as one of the malaises of the 20^th century by the United Nations in 1992, and later recognized as a rampant global issue by the WHO. The International Labor Organization (ILO) estimates that the costs incurred by occupational stress can account for 1 to 3.5% of the gross domestic product (GDP) of each country (12). The studies performed in Iran indicate that the prevalence of high occupational stress is about 14.4% (13, 14). The American Academy of Family Physicians (AAFP) has estimated that about two-thirds of those examined at their work environment or offices had symptoms of tension or stress (15). The literature on occupational stress reveal that 30% of the work force in developed countries suffer from job stress, whereas this figure is much greater in developing countries (16). The long-term exposure to stress can cause burnout (15). Occupational stress is characterized by the three groups of physical, psychological, and behavioral symptoms.

Previous studies suggest that high stress arising from work is associated with mild mental disorders. Problems such as excessive absenteeism, substance and drugs abuse, apathy at work, and low motivation are greater in stressed people, and these problems affect their job satisfaction and mental health. Job satisfaction is one of the most important factors contributing to improved performance, high efficiency, and reduced injuries (7). Stress is directly linked to the job satisfaction and performance of an individual, acting as one of the underlying components of health, safety, and comfort. Individuals with low job satisfaction display poor mental health (13). Unsatisfied employees are more vulnerable to physical and mental symptoms and absenteeism. The implementation of any plan to prevent and reduce job stress, promote job satisfaction, reduce workload, and increase general health requires deeper insights about these factors and their severity. Considering the paucity of research on the health conditions of welfare employees and their working conditions, this study seeks to investigate the relationship between general health, occupational stress, and workload.

Materials and Methods

This was a cross-sectional descriptive-correlational study on 63 full-time employees of 3 welfare centers of Tehran, Iran, including the Care Center for the Mentally Ill, Care Center for the Disabled, and Care Center for the Elderly. Study subjects were selected using the the census method. The data collection tools consisted of the NASA Task Load Index (NASA-TLX) to evaluate workload, Occupational Stress Inventory (OSI) to evaluate occupational stress, and the General Health Questionnaire (GHQ-28) to examine the general health of the study population.

Moreover, another questionnaire was used to collect demographic data of the employees. Statistical data analysis was carried out using SPSS (version 17, SPSS Inc., Chicago, IL, USA) through computing the Spearman and Pearson correlation coefficients and step-wise regression. To observe the ethics of research, the necessary information about the goals of the study were given to the participants, they were assured of the confidentiality of study, and written consents were obtained from them before completing the OSI, NASA-TLX, and GHQ.

NASA-TLX: This questionnaire consists of two parts with the first part investigating overall workload and the second part determining the importance of each subscale of workload in the view of the respondent.

Part one: Evaluation of the relative importance of each subscale of workload

The subscales examined in this study include:

Mental demand: It refers to the extent of psychological activities (e.g. reflection, decision-making, calculation, remembering past events, and etc.), whether a task is simple, difficult, complex, or convenient.

Physical demand: It refers to the amount of physical activity required (e.g. pushing, pulling, physical movement, and etc.), whether the task is easy or demanding, requires quick reaction or is physically laborious.

Temporal demand: It refers to the pressure exerted as a result of time restriction of the task and whether it should be performed quickly or slowly.

Effort: It refers to the extent of hard work (in terms of intellectual and physical requirements) required to deliver the work at a desirable level.

Performance: It refers to the degree of achievement in the intended goals (occupational objectives) by an individual or their satisfaction with these goals.

Frustration: It refers to the level of frustration, dissatisfaction, annoyance, and stress a person is experiencing (it is the opposite of hopefulness, peace, and satisfaction).

Part two: Determining the level of each subscale of workload (in a scale of 0-100)

The respondent’s/participant’s scores in each subscale of workload, in accordance with their personal condition, ranged from 0 to 100.

In the analytic hierarchy process (AHP), the importance of each dimension is compared to other dimensions (this one-to-one analysis was part of the questionnaire where the respondents were required to answer the questions based on their conditions and criteria specified in the definition of each in the first part of the questionnaire. The analysis was performed on the basis of choices made by the respondents. In other words, the parameters were presented in the questionnaire and choices/comparisons were made by the respondents. The weight of each dimension was obtained from the total workload of each respondent. Then, multiplying the weight of each workload subscale (a value between 0 and 1) by the specified level (a number between 0 and 100), the total workload of each individual was calculated as a number between 0 and 100.

GHQ-28 This psychological questionnaire is the most well-known screening tool in psychiatry. It was designed by Goldberg and Hillier (17). This 28-item questionnaire consists of 4 scales each containing 7 items that evaluate physical symptoms, anxiety, impaired social functioning, and depression. The intensity of these scales is evaluated on a range of extremely low to extremely high with each item having a score of 0-3. In this study, which was carried out in Iran, a cutoff score of 21 was obtained (18).

Osipow job stress questionnaire: This questionnaire, which was designed by Osipow and Spokane in 1987, is an occupational stress measurement instrument (19). In Iran this questionnaire has been used in several studies and its validity and reliability (with a Cronbach's alpha of 0.89) has been confirmed. (13, 31, 32), in the study by Namavar et al. in 2013, a reliability of 0.87 was achieved using Cronbach's alpha (20).

The OSI is scored based on a 5-point Likert scale and consists of three parts. In this study, only the first part of the questionnaire has been used. This part is organized in 6 subscales, each containing 10 items. The first subscale is role workload, which evaluates the reaction of a person to their work environment. The second subscale is role insufficiency, which determines the consistency between skills, knowledge, and educational and empirical features relative to the job environment requirements. The third subscale is role duality, which is concerned with the knowledge of priorities and expectations of the work environment and evaluation criteria. The fourth subscale is role boundary, which is related to the contradictions among work ethic and the requirements of the expected role. The fifth subscale is responsibility, which determines the sense of accountability in terms of efficiency and welfare of others. The sixth subscale is physical environment, which is related to exposure to unsuitable physical environment. In this scale, occupational stress is evaluated at four levels of low, normal, moderate, and severe stress.

In this research, the necessary permissions were obtained from the Research Deputy of Gonabad University of Medical Sciences, Iran, and presented to the Welfare Center of Tehran. Then, the questionnaires were distributed among the employees, with the assurance that their participation was voluntary and their information would remain confidential and anonymous.

Table 2: Results of measuring job stress in welfare employees

Role workload	Role insufficiency	Role duality	Role boundary	Responsibility	Physical environment	Job stress		Welfare Center
24.8	27.04	23.28	25.44	26.40	19.64	146.60	Mean	Care Center for the Mentally Ill
4.5	5.891	6.554	4.194	4.262	4.881	17.176	SD
19	14	10	19	16	13	118	Min
34	38	37	37	35	30	182	Max
25.25	29.82	23.86	26.89	27.32	25.14	158.29	Mean	Care Center for the Disabled
6.479	9.858	8.077	5.202	6.337	6.508	26.425	SD
12	12	10	18	18	15	118	Min
36	47	37	37	39	38	206	Max
25.90	24.70	20.50	20.20	34.00	21.20	146.50	Mean	Care Center for the Elderly
7.355	6.038	5.061	5.574	3.333	8.548	25.127	SD
16	17	15	12	27	15	114	Min
33	35	28	28	37	45	195	Max

Table 3: Results of the general health of welfare employees

Physical symptoms	Anxiety and sleep disorders	Social disorders	Depression	General health		Welfare center
5.72	5.24	8.44	1.72	21.12	Mean	Care Center for the Mentally Ill
3.53	4.82	2.74	2.82	9.01	SD
1	0	4	0	11	Min
15	14	15	9	39	Max
6.61	7.04	9.07	4.57	27.21	Mean	Care Center for the Disabled
3.56	3.69	4.56	4.63	9.79	SD
1	0	2	0	7	Min
13	14	18	14	42	Max
3.09	3.8	14.60	2.6	24.9	Mean	Care Center for the Elderly
2.42	4.96	5.52	3.92	6.20	SD
2	0	6	0	16	Min
10	14	19	11	39	Max

To determine the role of the occupational stress subscales on general health, first the relationship between each subscale and general health was investigated. The results of table 5 show that responsibility and physical environment are significantly related to general health (P < 0.050).

The results of statistical analysis suggest that the regression of physical environment and responsibility on general health is significant. However, the model has a weak predictive power with the regression model explaining only 29% of the changes in variables (R² = 0.292). The regression model is as follows:

General health = 0.382* responsibility + 0.681* physical environment

Discussion

According to the results, considering the cutoff point of 21 as the separating line between health and non-health in the study population, the general health score of welfare employees was too high (24.43), suggesting the undesirability of their health conditions. Amongst the different subscales of general health, social disorders had the highest score. The social aspect of health can be seen as the most complex and yet controversial aspect of the health system.

The WHO introduces social health as one of the key components of health, but due to lack of valid instrument, this concept is still the subject of political and social debates (6). Several studies have substantiated the effect of the work environment and work requirements on general health. There is a paucity of studies on occupational health of welfare employees. The study by Movallali et al. on the quality of general health in mothers of hearing and hearing-impaired children indicated that the general health of mothers of hearing children was greater than that of mothers of hearing-impaired children (21).

The results of the study revealed that workload, with a mean score of 55.76, was at the medium level. The two subscales of mental demand and effort had the highest and frustration and performance subscales the lowest scores among the subscales of NASA-TLX. This, in turn, suggests the high mental demand and physical requirements of work in welfare centers. There are few studies on the evaluation of workload in welfare employees using the NASA-TLX.

The level of job stress in the study population was normal according to the rating scale of 60 to 107 (without stress), 108-203 (normal), 204-251 (medium), and 252-300 (severe). This indicated that welfare employees were not exposed to high levels of stress in their work environment. The analysis of job stress subscales showed that role workload, role insufficiency, responsibility, and physical environment were at the normal range, and role duality and role boundary were at the medium range.

The study suggested that the effect of responsibility on increasing job stress was greater than other variables. The results of workload regression on job stress were shown to be significant. Moreover, statistical data indicated that the regression of job stress and frustration on general health was significant. In determining the role of each dimension, only the significant relationship between responsibility and physical environment, and general health was corroborated.

The study by Yadegarfar et al. revealed that high stress increased the risk of some cardiovascular risk factors (14). The study by Navidian et al. showed a significant relationship between the intensity of stress factors and general health of nurses. That is, an increase in intensity of stress factors was associated with deteriorated general health (negative correlation coefficient) (6). Most relevant studies in this field confirm the relationship between the intensity of job stress experienced by individuals and their mental health status (6, 22, 23).

The relationship between occupational stress and many cardiovascular risk factors, including diabetes (24), body mass index (25), hypertension, hyperlipidemia, overweight, smoking, alcohol consumption and its severity, triglyceride and lipoproteins levels with high and low density (26-28), heart rhythm, and metabolic syndrome (28), have been investigated. However, the findings in this field are incongruous (26, 29, 30). There have been numerous studies on job stress in Western countries. But due to the different in job values and perceived characteristics of work environment, motivation and attitude in Iran and other country there is a high chance of obtaining different results in Iran. Of course, this inconsistency is not far from expectation since stress and workload, as psychological phenomena, are affected by a range of factors, including job-induced stress and workload. There are many risk factors that can intensify job stress and workload. Nevertheless, it should be noted that stress and workload are to a large extent generated by risk factors stimulated by individuals. In addition to environmental factors and stressors, intrapersonal factors such as cognitive, attitudinal, emotional, and personal components are also involved in increasing stress and workload.

According to the results of other studies, measures, such as recruiting more employees, and therefore, reducing the workload, utilizing the services of people interested and experienced in these fields, providing a comfortable and appropriate physical environment, dedicating a break time for relaxation after critical situations, and alleviating the workload, can help reduce the above stressors (6). By identifying stressors in these jobs and attempting to reduce them through reforms in organizational, physical, and caring structures, we can reduce stress and promote the physical and psychological health and job satisfaction of employees. This will result in the increasing of the quality of life of people engaged in these jobs. It is recommended that at the outset of recruiting, some psychological tests, such as personality characteristics, be administered to the applicants and regular examinations be offered to them at centers specialized in occupational medicine services. Moreover, regular training programs and medical and psychological education should be provided for these individuals.

Conclusions

Given the results of the present study and with a view of the body of research on personality characteristics and job stress, in can be concluded that there is a significant relationship between some basic subscales of workload, job stress, and general health.

The present study had a number of limitations. The research data are based on self-monitoring, which may be biased. Moreover, this research is limited to social welfare employees in the city of Tehran. Thus, caution should be practiced in generalizing its results to other groups. In addition, since it is a correlational study, it is difficult to discover causal relationship. Thus, to identify the causes of job stress, workload, and general health, experimental research or causal studies are required.

Acknowledgement

The authors are grateful to faculty members of the Department of Occupational Health in Tehran University of Medical Sciences, and all managers and staff of welfare centers in Tehran who helped us in this project.

Conflict of interests: None declared.

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* Corresponding author: Roohollah Hajizadeh, Dept. of Occupational Health Engineering, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran.

Email: roohalahhajizade@gmail.com

	Mental demand	Physical demand	Temporal demand	Effort	Performance	Frustration	Total workload
Mean	70.27	62.8	54.98	67.03	40.86	39.38	55.76
SD	26.48	27.04	26.86	25.09	30.69	31.88	16.91
Min	2	8	0	3	0	0	20.67
Max	100	100	100	100	100	100	100

General health		Frustration	Performance	Effort	Temporal demand	Physical demand	Mental demand
	Correlation coefficient	0.30	0.10	0.10	*0.20	0.18	0.09
	P	0.01	0.39	0.40	0.84	0.15	0.47

General health		Environment	Responsibility	Role duality	Role insufficiency	Role workload
	Correlation coefficient	*0.51	0.27	0.08	*0.27	0.17	0.18
	P	>0.001	0.03	0.48	0.10	0.17	0.15