Epidemiological study (observational study)

The Potential Bioeffects of Extremely Low Frequency Electromagnetic Fields on Melatonin Levels & Related Oxidative Stress in Electric Utility Workers Exposed to 132 kV Substation epidem.

By: Tiwari R, Bhargava SC, Ahuja YR

Published in: J Electromagn Anal 2013; 5 (11): 393-403

Aim of study (acc. to author)

A study was conducted in India to investigate the melatonin levels and oxidative stress parameters in electric utility workers with exposure to extremely low frequency magnetic fields.

Further details

Further results on this study population are published in Tiwari et al (2015).
A blood sample for determining melatonin level and other blood parameters was collected in the morning between 9 AM to 10 AM from each study participant.

Endpoint/type of risk estimation

melatonin level in plasma, oxidative stress parameters: malondialdehyde level in plasma (lipid peroxidation), nitric oxide level in serum, enzyme activities of antioxidative enzymes (superoxide dismutase, glutathione peroxidase and catalase) in erythrocyte suspension

Exposure

- 50/60 Hz
- magnetic field
- power transmission line
- electrical substation
- occupational

Assessment

questionnaire: work characteristics, linemen, casual labor and live-line workers, duration of exposure in years, duration of exposure in hours per day and vicinity from substation

Exposure groups

Group	Description
Reference group 1	occupational exposure to extremely low frequency magnetic fields: no
Group 2	occupational exposure to extremely low frequency magnetic fields: yes
Group 3	duration of occupational exposure to extremely low frequency magnetic fields: 1 - 4 years
Group 4	duration of occupational exposure to extremely low frequency magnetic fields: 5 - 12 years
Group 5	duration of occupational exposure to extremely low frequency magnetic fields: 13 - 28 years
Group 6	daily duration of occupational exposure to extremely low frequency magnetic fields: 1 - 3 hours/day
Group 7	daily duration of occupational exposure to extremely low frequency magnetic fields: 3 - 6 hours/day
Group 8	daily duration of occupational exposure to extremely low frequency magnetic fields: 6 - 9 hours/day
Group 9	exposure based on job titles: low (e.g. administrative workers)
Group 10	exposure based on job titles: medium (e.g. maintenance workers)
Group 11	exposure based on job titles: high (e.g. live-line workers)

Population

Group:
- men
Age: 20–58 years
Characteristics: electric utility workers maintenance and installation of power lines
Observation period: not stated
Study location: India (Hyderabad)

Study size

Type	Value
Total	142

Results (acc. to author)

The measured mean occupational magnetic field strength in the 132 kV substation at Hyderabad, India was 3.5 µT (SD ± 2.01), while environmental non-occupational exposure was 0.0015 µT (SD ± 0.001). The electric utility workers were exposed for a mean duration of 9.27 (±7.23) years at an average of 9 h per day.
The plasma melatonin level was significantly decreased in high exposed workers (group 11) when compared to the low and medium exposed groups (groups 9 and 10). The lipid peroxidation and nitric oxide levels were significantly increased in all exposed subjects (group 2) in comparison to the control group (group 1). The enzyme activities of antioxidative enzymes of exposed workers (group 2) were significantly lowered when compared to the control group (group 1).

Study funded by

University Grants Commission (UGC), India

Hosseinabadi MB et al. (2019): Effect of long-term occupational exposure to extremely low-frequency electromagnetic fields on proinflammatory cytokine and hematological parameters
Zhang D et al. (2017): Resveratrol may reverse the effects of long-term occupational exposure to electromagnetic fields on workers of a power plant
Zhang Y et al. (2016): Effects of dietary green tea polyphenol supplementation on the health of workers exposed to high-voltage power lines
Tiwari R et al. (2015): Epinephrine, DNA integrity and oxidative stress in workers exposed to extremely low-frequency electromagnetic fields (ELF-EMFs) at 132 kV substations
Touitou Y et al. (2013): Long-term (up to 20 years) effects of 50-Hz magnetic field exposure on immune system and hematological parameters in healthy men
El-Helaly M et al. (2010): Oxidative stress, melatonin level, and sleep insufficiency among electronic equipment repairers
Sharifian A et al. (2009): Effect of extremely low frequency magnetic field on antioxidant activity in plasma and red blood cells in spot welders
Genuis SJ (2008): Fielding a current idea: exploring the public health impact of electromagnetic radiation
Di Giampaolo L et al. (2006): Follow up study on the immune response to low frequency electromagnetic fields in men and women working in a museum
Gobba F et al. (2006): No association between occupational exposure to ELF magnetic field and urinary 6-sulfatoximelatonin in workers
Ichinose TY et al. (2004): Immune markers and ornithine decarboxylase activity among electric utility workers
Noonan CW et al. (2002): Relationship between amyloid beta protein and melatonin metabolite in a study of electric utility workers
Dasdag S et al. (2002): Effects of extremely low frequency electromagnetic fields on hematologic and immunologic parameters in welders
Burch JB et al. (2000): Melatonin metabolite levels in workers exposed to 60-Hz magnetic fields: work in substations and with 3-phase conductors
Juutilainen J et al. (2000): Nocturnal 6-hydroxymelatonin sulfate excretion in female workers exposed to magnetic fields
Kula B et al. (1999): Effect of Electromagnetic Field on Serum Biochemical Parameters in Steelworkers
Bonhomme-Faivre L et al. (1998): Study of human neurovegetative and hematologic effects of environmental low-frequency (50-Hz) electromagnetic fields produced by transformers