The "Brick" Takes a Beating
While you were blabbing away, your cell phone took a hit this week. Basically cell phones were slammed from two sides. As much as any modern product, the cell phone is about as integrated as a piece of plastic can get into our lives. In 2002, 2% of Americans gave up their landlines for cell phones; in 2009, it was about 1/3 of cell phone users. Similar to Americans and their cars, there are countries in Europe where cell phones outnumber the population.
Cell Phones Cause Cancer
So what is the recent cell phone scuttlebutt? The World Health Organization (WHO) issued a press release this week that classified radiofrequency magnetic fields such as that generated by wireless cell phones as “possibly carcinogenic” (cancer causing). A group of 31 scientists from 14 countries met in rural France to review the published evidence linking cell phones and cancer. In a consensus statement, they felt that the risk of a brain cancer called glioma is 40% higher in individuals who use cell phones for > 30 minutes daily for 10 years. It was this data that drove the panel to label cell phones as possibly carcinogenic. For perspective, the pesticide DDT, coffee (acrylamide), alcoholic beverages and night shift work are also considered “possibly carcinogenic” by the WHO.
Cell Phones Reduce Male Fertility
About half a dozen studies involving 750 men have been published over the past 8 years that attempt to link cell phone use with impaired semen quality. Importantly, only semen quality, and not actual fertility, is commonly studied. For the most part, cell phone use in these studies is associated with lower sperm motility and lower sperm numbers. However, a recent Canadian-Austrian report from a couple of weeks ago also suggests that this effect may be hormonal in nature, since cell phones in this study were associated with worse semen quality but higher testosterone levels.
To one practiced in the art of male reproductive medicine, these studies are both curious and puzzling. One huge problem with “epidemiologic” studies is that they can only postulate an association between A and B, but do not prove causality or that A causes B. In the realm of cell phones, they tend to ignore major covariates such as life style issues (smoking, hot tubs, recreational drug use), occupational history and other sources of radiofrequency exposure such as radio towers, personal digital assistants (PDA), Bluetooth devices and computers that might also impact semen quality. But lets get even more basic: a single semen analysis does not a man make as semen quality in any individual can vary quite widely from day to day, season to season and even year to year. Just take a gander at our hot tub study and its effect on semen quality to get a small taste what these epidemiologic studies are up against in terms of bias.
What would be most convincing of a relationship between cell phones and male infertility or cancer would be mechanistic research that shows biological plausibility or causality of the link. This is difficult but essential, especially if what is at stake is a piece of plastic owned and coddled by 5 billion of our 6.9 billion human inhabitants on this good earth.