THE DETAILS: Forty-eight men participated in the study, 24 of whom had used a cellphone for at least a year and 24 who had never owned a cellphone. The cellphone users were an average of 10 years younger than the nonusers, and all of them carried their cellphones on their right hips in a pouch or on a belt. Each person carried his cellphone there for an average of 11 hours per day. After having body weight, height, and body mass index measured, each participant's bone mineral density was measured. While both groups had higher bone density in their left hips than in their right, the difference in bone density was greater among cellphone users than nonusers, suggesting that carrying a cellphone on one's right hip might play a role in lower bone density there. The larger difference was consistent across all cellphone users, regardless of age, weight or body mass index, all of which can play a role in bone density loss.
WHAT IT MEANS: Like most scientists who study the impact of cellphones on health, Fernando Saravi, MD, PhD, professor at the School of Nuclear Medicine and department of morphology and physiology at the National University of Cuyo, Mendoza, Argentina, and author of the study, is cautious in interpreting his results, calling them "interesting" but noting the study's small size and the need for larger studies to confirm what he found. "Having said that, I think that cellphones should be kept as far away from the body as possible most of the time," he says. "I'm particularly concerned with children, who will presumably be exposed to cellphone radiation for decades, giving time for possible adverse effects to develop."
Dr. Saravi's research adds to a growing body of evidence suggesting that cellphones do inflict slight, imperceptible changes to our physiology, including one study published last year finding that pregnant mothers who used cellphones frequently were more likely to have children with behavioral problems. And this past February, a study published in the Journal of the American Medical Association found that a 50-minute cellphone call could increase brain glucose metabolism, a marker of brain activity, due to the influence of low-level radio frequencies emitted as the phones try to connect to a nearby tower. The authors of that study weren't sure what the implications of that finding might be, but they did conclude that their evidence shows that cellphones do in fact impact our brains.
Dr. Saravi says that his results suggest that cellphones could increase a man's chances of developing osteoporosis. Though it's unlikely that mobile phones alone could cause the disease, "osteoporosis is often caused by several factors working together like aging, lack of physical activity, and cigarette smoking, to name a few," he says. "In this context, perhaps the influence of phones could add to other known risk factors."
"My point is that one should not take for granted that since cellphones do not cause significant effects this means that they are harmless," Dr. Saravi adds.
There are easy ways to protect your bones without having to forfeit your phone. Here are a few tips:
• Keep it away from you. "I myself carry my phone in a pocket close to the chest when I'm walking, but leave it on the desk while working at my office or lab," Dr. Saravi says. Avoid carrying it in a pants pocket, as the heat from cellphones is known to damage sperm, which can hamper a man's fertility.
• Go hands-free, and sit still. Using a headset or the speakerphone is the easiest way to limit cellphone radiation to your brain, along with placing your phone as far from you as is feasible when talking. The phones emit higher levels of radiation while they're in use and searching for a tower (as when you're in a moving vehicle). They also emit higher radiation levels when you're moving around, so park yourself in a comfortable chair and sit still during your conversations.
• Use common sense around kids. Don't use your BlackBerry or iPhone to play lullabies to your baby in her crib, and don't let a small child spend too long talking, watching movies, or playing games on a cellphone. Researchers don't currently know what levels of radiation a child is exposed to when he's using a cellphone as entertainment, but it's best to err on the side of caution.
• Send a text. Text messages require less work from your phone and, thus, you're exposed to much less radiation when sending a text than when talking on the phone. Texts are shorter, healthier, and mean you can avoid all the idle chit-chat that takes up so much time during phone calls.