Does your cell phone increase your risk of brain cancer? Does it affect your skin or your sperm viability? Is it safe for pregnant women or children? Should you keep it in your bag, on your belt, in your pants or shirt pocket? Should you use a hands-free headset? Are present cell phone safety standards strict enough?
You don't know? You're not alone.
With some 4 to 5 billion cell phones now in use worldwide and hundreds of studies seeking evidence of their health effects published in peer-reviewed journals over the last 10 years, there's precious little scientific certainty over whether cell phones pose any danger to those using them.
For nearly every study that reports an effect, another, just as carefully conducted, finds none. All of which leaves journalists, consumer advocates, regulatory agencies, politicians, industry spokespersons, and cell phone users able to choose and interpret the results they prefer, or ignore the ones they don't.
Do you, for instance, cite the studies that report adverse effects on sperm viability and motility, due to exposure to cell phone radiation or the studies that showed no - or mixed - results?
Do you cite the 2001 study that found increased incidence of uveal melanoma (a cancer of the eye) among frequent cell phone users, or the 2009 study by the same authors that, in reassessing their data, found no increase?
Do you cite the Israeli study that found an association between salivary gland cancer and heavy use of cell phones or the Swedish study that found none?
Do you parse the data and report only those results that have found effects - no matter how small - without citing studies that found no effects?
In its much-cited review of cell phone studies, the Environmental Working Group has done just that, reporting, for instance, that 'a study from the University of California, Los Angeles, found a correlation between prenatal exposure to cell phone radiation and behavioral problems in children.'
But the group left out the study's very next sentence acknowledging that the association may be 'noncausal and may be due to unmeasured confounding.'Cell phones produce 'non-ionizing' radiation, which, unlike X- or gamma rays, doesn't damage DNA by stripping away electrons from molecules in cell tissue. Radiofrequency energy does, however, produce heat and, at high enough levels, can damage cell tissue.
This, in the late 1990s, prompted the U.S. Federal Communications Commission (FCC) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) in Europe to set limits on cell phones' Specific Absorption Rate (SAR) - the measure of the amount of radiofrequency energy a cell phone user absorbs - at, respectively, 1.6 and 2.0 watts per kilogram.
The effects of cell phones have proven difficult to assess because they are relatively new, the way and the amount they're used continues to evolve, and the problems that cell phones might cause are hard to detect. Brain cancers, for instance, are very rare cancers. They affect only some 18 out of every 100,000 people. But the fact that there's been no recent increase in the numbers may be meaningless with regard to cell phone use since brain cancers are very slow-growing.
The question remains, however, whether these standards are sufficient to protect against long-term exposures and whether the buildup of heat in cell tissues is more damaging where there's less blood flow to dissipate it, such as the outer ear, brain, skin, or testes.