By Dr. Sanjay Gupta
Chief Medical Correspondent

Last night, I was part of a fascinating discussion on “Larry King Live” about cell phones and their health risks. (watch) To be clear, most of the established scientific community thinks there is no reason for concern. There were, however, some strong voices on each side of the issue, including neurosurgeon Vini Khurana from Australia. He is convinced, after looking at hundreds of studies, that not only do cell phones cause health problems such as brain tumors, but also they will eventually be considered a bigger health risk than asbestos and even cigarettes.

Wow.

Now, I expected a staunch defense from the American Cancer Society, but instead I heard a more tepid response from Dr. Michael Thun. His bottom-line conclusion is that the studies that currently exist don’t show any reason for concern - but - the studies aren’t definitive in showing that they are safe either. Not exactly reassuring.

Over the last year, I have reviewed nearly a hundred studies on this topic, including the 19 large epidemiological studies. I urge you to do the same and read carefully to see what you think. Here is an example from a Swedish paper showing no increased risk of a brain tumor, known as acoustic neuroma. (see study) As you read the paper, you will find they defined a “regular” cell phone user as someone who uses a cell phone once per week during six months or more. I don’t know about you, but everyone I know uses his or her cell phones much more frequently than that. So, just how reliable are some of these studies?

Furthermore, many of the studies published since 2000 followed patients only three years on average. And, even a Danish study that did have longer-term follow-up excluded anyone under the age of 18. So, what about children who will presumably be using these phones for the rest of their lives?

Mobile devices give off non-ionizing radiation radio frequency. This is different from the ionizing radiation of an X-ray, which everyone agrees can be harmful in large doses. The recommendation by the two neurosurgeons on the panel yesterday – Khurana and Dr. Keith Black, chairman of neurosurgery at Cedars-Sinai Medical Center in Los Angeles - wear a wired ear piece. Even Bluetooth devices give off some radiation, although at lower doses. Don’t carry your cell phone in your pocket; instead put it in a holster that meets industry standards.

What do you think? As Larry reminded us last night, it took a long time to develop a cause-and-effect relationship between cigarettes and lung cancer. Nowadays, everyone knows it exists. Is the same thing happening with cell phones? (more from Dr. Gupta on cell phones and cancer)

Editor’s Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

By Dr. Sanjay Gupta
CNN Chief Medical Correspondent

I am one of those people who is on his cell phone all the time. Between the hospital and my job as a reporter, I get a lot of calls, especially when I am on the road. So, like many people, I pay attention when I read new studies about cell phones and possible health effects. The good news is that most of the studies out there have shown no reason to worry. In fact one study out of Denmark of 52,000 cell phone users who’d used cells for 10 plus years found the incidence of tumors was even less than the general population. The cell phone industry is quick to point out that “the overwhelming majority of studies show wireless phones do not pose a health risk.”

So, what to make of the fact that Dr. Vini Khurana out of Australia and Dr. Keith Black out of Los Angeles, who are both neurosurgeons, have voiced concerns about cell phones and brain cancer? And, just today, there is a new study of cell phones and pregnant women. That study found women who used cell phone two to three times a day while pregnant had children that were 54 percent more likely to develop ADHD and other behavioral problems. And, if those children used cell phones before age 7, they were 18 percent more likely to develop ADHD. (Watch Dr. Gupta’s report here)

Now, as we dug into this story, we found even the study authors acknowledge that there is no causal link. That means there is no cause-and-effect relationship. It could be that young children who are on their cell phones a lot are also more prone to developing ADHD. Or, on the other hand it could mean that cell phones cause problems we haven’t even imagined. We don’t know. What we do know: Most cell phones emit between 850 and 1900 MHz of non-ionizing radiofrequency (RF) energy. It is different from the ionizing radiation from a medical X-ray. It can also make your speakers hum when you walk by them.

So, what do you think? Black, who is also the chair of neurosurgery at Cedars Sinai Hospital, believes that the science simply hasn’t caught up and that we would all be well served by taking precautions. He always uses an earpiece. What about you? Are you concerned about cell phones and health effects or is this not a big deal?

Editor’s Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.