August 16, 2009
Keep That Phone Out of Your Trouser Pocket!
Once Again, Australia’s Aitken Sees DNA Damage
It's the strongest warning yet. John
Aitken, a well-known fertility researcher, is advising men who want
to have children not to keep active mobile phones below their waists. This issue, he says, "deserves our immediate attention."
Aitken's research group at the University of Newcastle in Australia has found that human sperm exposed to mobile phone radiation (1.8 GHz) for 16 hours had reduced vitality and motility, two key indices
of fertility. Notably, he has also confirmed his own previous study, published in 2005, which showed that RF radiation
could lead to DNA damage. In that earlier experiment, he had exposed mice to 900 MHz signals and then looked at the animals' sperm, in contrast to the new study in which he exposed semen collected from
human volunteers.
The new data show striking dose responses for all three effects over a wide range of SARs —above 0.4 W/Kg and up to 27.5 W/Kg.
The changes in motility and vitality became statistically significant at 1 W/Kg and the DNA damage at 2.8 W/Kg. In all cases, the statistical reliability of the effects became much more
significant with higher SARs. These new results appear in a paper published on
July 31 in PLoS ONE, a Web-based, peer-reviewed journal. All Public Library of Science journals offer free access to all.
"After 16 hours exposure, there was clear evidence of DNA damage," Aitken said
at a fertility conference in Brisbane last fall when he first presented these findings. Aitken is the director of the Australian Research Council's
Center of Excellence in Biotechnology and Development.
"Several independent lines of evidence suggest that RF-EMR has the potential to influence semen quality and could be an important contributor
to DNA damage in the male germ line," Aitken told Microwave News. He said that he would like to see more studies done, especially ones with the statistical power
to determine whether RF can indeed affect male fertility.
In an interview published
last month, Martine Hours, the chief science advisor to the
French RF research program, also called for more fertility studies.
Importantly, Aitken also demonstrates a "potential causative mechanism" as to how RF radiation can lead to DNA damage. He acknowledges that cell phone signals
do not have enough energy to directly break chemical bonds, but, he goes on, "[T]his form of radiation may have other effects on larger scale systems such as
cells and organelles, which stem from the perturbation of charged molecules and the disruption of electron flow." Specifically he believes that the RF can cause leakage of electrons from the
mitochondria and produce reactive oxygen species
(ROS), which in turn can attack DNA. This process, he states, is unrelated to thermal stress.
Over a decade ago in a follow-up to their landmark 1995
study which showed that RF radiation
can lead to DNA breaks in the brains of exposed rats, Henry Lai and
N.P. Singh
showed that the DNA breaks were caused by free radicals. (For more on EMFs and DNA damage, see the recent review by Lai, Singh and Jerry Phillips of the University of Colorado in Colorado Springs.)
Aitken found an analogous dose-response relationship for the production of free radicals with increasing SAR —a highly significant one— to the ones for motility, vitality and DNA damage. "[T]he profiles of all the observed
effects with respect to SAR were intriguingly similar, suggesting a common underlying mechanism," Aitken writes.
Another of Aitken's results may also be quite meaningful: Only a subset of the sperm cells was vulnerable to RF-induced oxidative stress. "[A]ll of the responses examined showed an extremely
rapid change at low SAR exposures that then reached a plateau at a point where around 30% of the sperm population was affected," Aitken reports, but he is quick to add,
"[T]his does not mean that a majority of spermatozoa would not, ultimately, be affected by RF-EMR in vivo." It might well depend on the duration of the exposure, he says.
These new results from Australia are consistent with those of Ashok Agarwal
and coworkers at the Cleveland Clinic in Ohio. In a
paper published last year in Fertility and Sterility, Agarwal also reported decreases in sperm motility and viability
and increases in ROS in human semen. He concluded, "[K]eeping [a] cell phone in a trouser pocket in talk mode may negatively affect spermatozoa and impair male fertility." Yet, in a subsequent
interview
with Newsweek, when he was asked where he kept his phone, Agarwal replied: "In my pants pocket." Because, he explained, he does not use a hands-free set (the phone is on standby,
not talk mode, there, resulting in less exposure). And because "I already have two children."
Agarwal had previously observed an association between semen quality and cell phone use among men who had visited an infertility clinic. "Semen analysis … showed a decrease in
sperm count, motility, viability, and normal morphology with the increase in daily use of cell phone," he reported in that earlier paper,
also published in Fertility and Sterility. (For a piece on U.S. press coverage of some of Agarwal's early RF-fertility work, see our
posts of October 26 and 27, 2006.)
In the last few years, a second U.S. group (in
Wisconsin) as well as others in
Hungary,
Poland and
Turkey —that makes five countries in all—
have all shown detrimental effects of cell-phone use or cell-phone radiation on sperm.
In his 2005 paper on the effects of RF radiation on mice, Aitken suggested that
one possible implication of his findings is that the EMF link to childhood leukemia seen in residential epidemiological studies may in fact be due to their fathers' radiation exposure. He picks up this theme in his new
PLoS ONE paper:
"[T]he fact that sperm DNA is damaged by this form of radiation has additional implications for the health and wellbeing of children born to fathers who have experienced high levels of occupational or environmental exposure to RF-EMR around the time of conception."
August 17… Make that research teams in six countries, not five, that have implicated cell phones in causing harm to
male fertility (see yesterday's post). Last December, a group led by Nader Salama at Japan's Tokushima University medical school
reported that the sperm of rabbits, whose testes were exposed to 800 MHz radiation for eight hours
a day for 12 weeks, had lower counts and motility, as well as changes in the biological structures where the sperm is formed
(Seminiferous tubules). The counts and motility stayed relatively stable for the first few weeks
and then, in each case, took a sudden, big drop —in week six for counts and week eight for motility.
Salama used actual GSM phones in standby mode, which would mean relatively low exposures. This prompted Germany's Alex
Lerchl to express his "severe concerns" about the "exposure conditions" as well as the "reported biological effects." His
letter to the editor of the International Journal of
Andrology, was posted on journal's Web site on August 10. In his reply, Salama, who is now at the Alexandria Faculty of Medicine in Egypt,
stood by the results as originally published. Lerchl has emerged as a frequent and aggressive critic of those who publish papers showing mobile phone effects. For some time, he has tried to force the retraction of
two papers from Hugo Rüdiger's lab at the Medical University of Vienna showing cell-phone radiation induced DNA breaks. To date, Rüdiger has refused.