Epidemiological study (observational study)

Psychological effects of chronic exposure to 50 Hz magnetic fields in humans living near extra-high-voltage transmission lines epidem.

By: Beale IL, Pearce NE, Conroy DM, Henning MA, Murrell KA

Published in: Bioelectromagnetics 1997; 18 (8): 584-594

Aim of study (acc. to author)

A cross-sectional study was conducted in New Zealand to investigate the association between the exposure to magnetic fields of power lines and psychological and mental health.

Further details

The participants completed following neuropsychological tests: digit span test, trail making tests, digit symbol test, symbol-digit modality test, d2 cancellation test, selective reminding test, visual memory test. Furthermore they filled in the life changes questionnaire and the general health questionnaire-28.

Endpoint/type of risk estimation

psychological and mental health status (somatic symptoms, anxiety, social dysfunction, major depression), self-rated general health status over the past 6 months

Exposure

Assessment

measurement: magnetic flux densities at three places in each room where the participant spent one hour or more per day at average
calculation: average exposure: arithmetic mean of all readings taken in the two or three rooms in which the participant spent one hour or more per day on average. Time-integrated exposure: multiplying the average estimated hours spent in each room by the mean of the readings taken in the room, and summing across the rooms in which the participant spent one or more hours per day on average

Exposure groups

Group	Description
Reference group 1	1st quintil, mean average exposure: 0.057 µT; mean time integrated exposure: 0.640 µT-hour
Group 2	2nd quintil, mean average exposure: 0.209 µT; mean time integrated exposure: 2.756 µT-hour
Group 3	3rd quintil, mean average exposure: 0.392 µT; mean time integrated exposure: 5.333 µT-hour
Group 4	4th quintil, mean average exposure: 0.766 µT; mean time integrated exposure: 10.579 µT-hour
Group 5	5th quintil, mean average exposure: 1.944 µT; mean time integrated exposure: 30.761 µT-hour

Population

Group:
- men
- women
Age: 18–70 years
Characteristics: residents of houses in streets running beneath overhead transmission lines
Observation period: not stated
Study location: New Zealand (Auckland)

Study size

Type	Value
Evaluable	540

Statistical analysis method:

multiple linear regression analysis

(adjustment:

age
sex
socioeconomic status
life changes, self-rated health and perceived effect of powerlines on personal health

)

Results (acc. to author)

Performance on most memory and attention measures of the participants living close to power lines was unrelated to magnetic field exposure, but significant linear dose-response relationships were found between exposure and some psychological and mental health variables. In particular, higher time-integrated exposure was associated with poorer coding-test performance and more adverse health effects (anxiety, somatic symptoms, depression) . These associations were found to be independent of participants' beliefs about effects of electromagnetic fields.

Study funded by

not stated/no funding

Zahiroddin AR et al. (2006): Mental health status of employees in substations of electromagnetic fields at extremely low frequency in Tehran
Cheng K et al. (1996): In vivo 3-D distributions of electric fields in pig skin with rectangular pulse electrical current stimulation (RPECS)
McMahan S et al. (1994): Depressive symptomatology in women and residential proximity to high-voltage transmission lines
Poole C et al. (1993): Depressive symptoms and headaches in relation to proximity of residence to an alternating-current transmission line right-of-way
Dowson DI et al. (1988): Overhead high-voltage cables and recurrent headache and depressions
Perry FS et al. (1981): Environmental power-frequency magnetic fields and suicide