Journal of Occupational HealthVolume 62, Issue 1
Majid Bagheri Hosseinabadi, Narges Khanjani, Mohammad Hossein Ebrahimi, Seyed Habib Mousavi, Fereshteh Nazarkhani
First published: 25 July 2020
This study was designed to investigate the possible effect of exposure to extremely low frequency electromagnetic fields (ELF‐EMFs) on occupational burnout syndrome and the severity of depression experienced among thermal power plant workers and the role of oxidative stress.
In this cross‐sectional study, 115 power plant workers and 124 administrative personnel of a hospital were enrolled as exposed and unexposed groups, respectively, based on inclusion and exclusion criteria. Levels of oxidative stress biomarkers, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (Cat), and total antioxidant capacity were measured in serum samples. Exposure to electric and magnetic fields was measured using the IEEE Std C95.3.1 standard at each workstation. The burnout syndrome and the severity of depression were assessed using the Maslach Burnout and Beck Depression Inventory.
The levels of MDA and SOD were significantly lower in the exposed group than the unexposed group. The exposed group reported a higher prevalence of burnout syndrome and higher depression severity. Multiple linear regression showed that work experience, MDA level, and levels of exposure to magnetic fields are the most important predictor variables for burnout syndrome and severity of depression. In addition, a decrease in the level of Cat was significantly associated with increased burnout syndrome.
The thermal power plant workers exposed to ELF‐EMFs are at risk of burnout syndrome and depression. These effects may be caused directly by exposure to magnetic fields or indirectly due to increased oxidative stress indices.
The International Agency for Cancer Research has classified these fields as possibly carcinogenic to humans. The results of this study showed a significant relation between occupational exposure to magnetic fields, occupational burnout syndrome and depression severity. Moreover it was showed that levels of some indicators of oxidative stress had increased in the exposed group which may be the possible mechanism for the effects of exposure to ELF‐EMFs on burnout and depression. We showed in previous studies that exposure to these fields disturbs the antioxidant system balance, and leads to increased levels of malondialdehyde, catalase, and superoxide dismutase, which is also associated with poor sleep quality, stress, anxiety, and depression.18
In explaining the relation between exposure to magnetic fields and occupational burnout syndrome, some researchers think that exogenous stresses cause oxidative cellular stress, the formation of reactive oxygen species, reactive nitrogen species, and reactive products. These factors also cause mitochondrial metabolic dysfunction, which results in the lack of adenosine triphosphate (ATP) followed by a decrease in the cells function. This decrease in ATP levels is a detrimental factor in the occurrence of burnout syndrome. As a result, weak ambient magnetic fields (such as fields produced by transformers found in devices) and various radio frequency resonances, can increase the prevalence of burnout syndrome by increasing levels of free radicals and reactive products.46
This study had some strengths and weakness. One of the strengths was that the direct and indirect effects of exposure to magnetic fields were evaluated. Furthermore, we quantified exposure to electric and magnetic fields by measuring them in different workstations during normal work shifts. However, this cross‐sectional study cannot prove causality and was conducted on only one power plant, that makes it difficult to generalize the results to all thermal power plants. We had difficulty in shift classification because workers were working in three rotating shifts (morning, evening, and night) and the unexposed group were working in two shifts (morning and evening). Thus, we could not differentiate the effect of each shift on depression and burnout syndrome.52 We tried to find a control group with very similar work conditions that probably had the same level of workload, similar life style and diet. But we cannot be sure that their conditions were completely similar.