Yi, Yang, Gao, 2022

The Effort-Reward Imbalance Questionnaire (ERI) was used to measure the occupational stress of survey respondents. This scale was proposed by Siegrist (30) and adapted by Li et al. (31) into the Chinese edition of the ERI questionnaire, which has good reliability and validity (32). The questionnaire combined the environmental (paying, reward dimensions) and individual factors (intrinsic input dimensions) to interpret the psychological tension of the respondents. The questionnaire included 23 items in terms of external effort (6 items), reward (11 items), and intrinsic input (6 items). ERI ratio was used as the outcome indicator: ERI = external effort / (return ∗ C), where constant C = 6 / 11. An ERI ≤1 represents a low payhigh return, which indicates low-level occupational stress; an ERI > 1 represents a high pay-low return, indicating high-level occupational stress

The Occupational stress is measured by the Effort-Reward Imbalance Questionnaire (ERI), which includes questions related to both individual and environmental factors. The ERI value is calculated to determine the level of occupational stress. If the ERI value is less than or equal to 1, it indicates that the worker experiences a low level of stress at work. If the ERI value is greater than 1, it indicates that the worker experiences a high level of stress at work.

Coal chemical workers operate in a special nature, and their workplaces are often accompanied by various types of occupational hazards, such as high temperatures, coal soot, radiation, and toxic and harmful gases (25). Coal chemical workers are mostly manual workers, some types of work are highly dangerous and mentally stressful, the workplace unsafe conditions are high, and they are prone to work accidents. Coal chemical workers also face tense life pressure, work instability, and other factors, which makes them have great mental and psychological pressure. Studies have found that the population of psychological stressinduced diseases is increasingly large, resulting in a gradual decline or even loss of employees’ ability to work.

Coal chemical workers have a special work environment, often exposed to many occupational hazards such as high temperatures, coal dust, radiation, and toxic gases. Coal chemical workers may experience instability at work and pressure in their personal lives. All these factors create heavy mental and psychological stress. Studies have shown that stress-related illnesses are becoming more common, leading to a decline or even loss of workers’ ability to perform their jobs

A comparison of the work ability levels of coal chemical workers at different occupational stress levels showed that there were 860 people in ERI ≤ 1 (low-stress group) and 426 people in ERI >1 (high-stress group). The incidence of poor working ability in the high occupational stress group of coal chemical workers was higher than that in the low occupational stress group (χ 2 = 234.622, P < 0.001) The results showed that work ability and its dimensions were inversely correlated with external effort, occupational stress and mental disorders (P < 0.001). The ability to work and its dimensions were positively correlated with reward (P < 0.05).

The result show 67%( 860/1286) of coal chemical workers has ERI value ≤ 1, and this indicates they have low level of stress at work. 34% (426/1286) of the coal  chemical workers experience high level of stress at work. The work ability of people with high levels of stress is  lower compared to the people with low levels of stress. The working ability of inverse correlated to occupational stress.

The results showed that the interaction between occupational stress and mental disorder had a significant impact on work ability. High occupational stress∗ mental disorders (OR = 10.666, 95% CI: 6.443–17.658) are 10.666 times more likely to develop poor work ability than low occupational stress∗ no mental disorders. Occupational stress also had an indirect negative effect on the ability to work through mental health conditions. Higher levels of occupational stress were associated with poorer mental health levels. Relevant studies have also shown that in groups such as firefighters (61), police officers (62), medical staff (63), and workers (64), the level of occupational stress affected the mental health status to different degrees

stress in the workplace has a strong impact on employees’ ability to work. Employees who experience high workplace stress or mental disorders are over ten times more likely to have poor work ability compared to those with low workplace stress. Occupational stress is closely related to mental health, as higher stress levels can lead to mental health problems. Some professions face higher levels of occupational stress than others, though the degree of stress varies across job groups.

Due to its design, a causal relationship cannot be determined, and future research should consider longitudinal methods such as cohort studies to clarify causality. Second, some findings differ from previous research, which may be influenced by the sample composition, particularly the imbalance between male and female participants; therefore, future studies should aim for a more representative and balanced sample. Additionally, mental health status was assessed using the SCL-90 questionnaire rather than clinical evaluation by a certified psychiatrist, which may affect the accuracy of identifying mental disorders

The data analysis part seems quite complicated, and there are some software calculations related to probability and confidence levels. The statistical analysis is very sophisticated, and some statistical tests are not fully explained in the article, which makes it difficult for me to understand how the results were obtained. Such as SNK-q test, AMOS 26.0 software was used to analyze the relationship