Letters to the Editor |
Extremely low-frequency magnetic fields and fertility in welders
Dear Sir,Jensen et al. [1], in their otherwise admirable review of occupational exposures and male reproduction, state in relation to the reduced fertility of welders ‘Welders are exposed to rather high levels of extremely low-frequency electromagnetic radiation, but this exposure is not a likely cause (their reference, 52), ...’. However, the reference paper [2] does not provide justification for this statement. The paper describes a study of 36 metal workers/welders and their partners regarding their exposures to extremely low-frequency (ELF) fields and measures of fertility such as sperm analysis and fecundity. There are numerous problems with the exposure data.
The methodology of measuring the fields is derived from a previous paper [3] in which whole-body exposure to ELF fields was measured using a meter worn on the right waist. This is unlikely to be a reliable and accurate measure of exposure to the testes of welders (see Figure 1).
|
Welders typically carry the high-current electric leads over their left shoulder and the leads coil near their groin. Placing an ELF field meter on the right hip may be suitable as a measure of whole-body exposure but is not suitable as a measure of exposure to the testes which are likely to have intense localized exposure. Using inaccurate data obtained from the meter on the hip to analyze exposure in relation to semen analysis will produce meaningless results.
In addition, the metal workers/welders used in the fertility study only welded for 5.8% of their work time, which is nearly one-tenth of the 56% of time spent by shipyard welders [2]. Because the time spent welding by the subjects in the fertility study was minimal, exposure to ELF fields will also be minimal and unlikely to produce effects. The results cannot be extrapolated to welders in general.
It is highly questionable to use data from subjects with minimal daily exposures and poorly measured ELF fields as a basis for the statement ‘this exposure is not a likely cause’ of welders reduced fertility.
Specialist in Occupational Medicine, 9 Tyrone Street, Camberwell, Victoria 3124, Australia
e-mail: bruhoc{at}connexus.net.au
References
- Jensen TK, Bonde JP, Joffe M. The influence of occupational exposure on male reproductive function. Occup Med (Lond) (2006) 56:544–553.[CrossRef][Medline]
- Hjollund NH, Skotte JH, Kolstad HA, Bonde JP. Extremely low frequency magnetic fields and fertility: a follow up study of couples planning first pregnancies. The Danish First Pregnancy Planner Study. Occup Environ Med (1999) 56:253–255.
[Abstract/Free Full Text] - Skotte JH, Hjollund HI. Exposure of welders and other metal workers to ELF magnetic fields. Bioelectromagnetics (1997) 18:470–477.[CrossRef][Web of Science][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||