Everyday exposure to power frequency magnetic fields and associations with non-specific physical symptoms

Everyday exposure to power frequency magnetic fields and associations with non-specific physical symptoms

Bolte JF, Baliatsas C, Eikelboom T, van Kamp I. Everyday exposure to power frequency magnetic fields and associations with non-specific physical symptoms. Environ Pollut. 2014 Oct 25;196C:224-229. doi: 10.1016/j.envpol.2014.10.011. [Epub ahead of print].

Abstract

The aim of this study was to investigate the association between exposure to extremely low frequency magnetic fields (ELF MF), or power frequency fields, and non-specific physical symptoms (NSPS).

In a cross-sectional study, personal exposure to ELF MF was measured for 99 adults selected in and around Amsterdam, the Netherlands in 2009-2010. They were scored on 16 NSPS. As a cut-off point for the individual 24-h time weighted average exposure the 80-percentile (0.09 μT) was chosen.

As only one man scored "moderately high" on the somatisation scale against nine women, we decided to proceed analyses only with the 48 women.

The crude odds ratio (OR) for women was 8.50 (CI 95%: 1.73-46.75), suggesting that for women environmental exposure to ELF MF is associated with an increased score on NSPS.

As this is an exploratory cross-sectional study in a relatively small sample, no conclusions regarding causality can be drawn.

http://1.usa.gov/1yk5W4U

Highlights

• Electric devices generate exposure to extremely low frequency magnetic fields.

• The median 24-hours' time weighted average (TWA) exposure is 0.05 μT.

• The 80-percentile TWA exposure is 0.09 μT for both, men and women.

• Women score higher than men on non-specific physical symptoms (NSPS).

• Exposure of women above the 80-percentile is associated with increased NSPS score.

Excerpts

ELF EMF 24-h profiles were measured with an exposimeter of type Emdex Lite (Enertech consultants, Campbell, California, USA, www.enertech.net) that had to be worn in a pouch attached to the belt on the left hip. During sleep the exposimeter had to be put next to the bed within 50 cm from the head and not next to electric devices, such as alarmclocks. The Emdex Lite measures the magnetic flux density in a frequency range from 40 to 1000 Hz. The sampling frequency was set at every fourth second for three orthogonal axes. The lower detection limit is 0.005 μT, the upper detection limit is 70 μT. 

4.5. Precautionary implications for society

As the association is at the exposure level that occurs during everyday activities GP's and policymakers could reconsider whether to advise preventive control measures to reduce exposure. Because exposure drops dramatically with increased distance, preventive measures should focus on sources near the body. For instance, people could easily move sources further than 50 cm from their body, especially bedside appliances with relatively high exposure such as an electric alarm clock, DECT phone with docking station, cell phone with loader, or any other charger.

5. Conclusions

The outcomes of this study suggest that for women a time weighted average exposure to ELF MF above the 80 percentile of 0.09 μT is associated with (potentially) clinically relevant levels of NSPS. As this was an exploratory cross-sectional study in a small sample (48 women), no conclusions regarding causality can be drawn. We therefore recommend to replicate this study with considerably larger numbers of women and men, and preferably with a longitudinal design.

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Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

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