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Friday, April 15, 2011

Post #24 A Follow-up to the Risks of Cell Phones

I think employing the precautionary principle with cellphones is a reasonable idea depending on the circumstances. If it starts to impair your quality of life, I would argue the current safety profile of cellphones justifies a fairly liberal approach to their usage.

For example, as a pediatrician I get a lot of calls and I try to use my cellphone to return calls during downtime moments of my life so that when I get home I can maximize my time with my kids. I use my cellphone a lot (rather than waiting to arrive home and use my landline) and would not change this facet of my life as the risk of a brain tumor to me seems so remote and the time with my kids is tangible and valuable.

However with my kids, I will likely employ a stricter application of the precautionary principle. My children's skull bones are thinner secondary to physical immaturity and their brains are more plastic and still developing. Furthermore, their lifestyles will not dictate a heavy need for constant connectivity (at least not early on in life). Perhaps a cellphone that will only connect to my phone and my wife's phone? I doubt that this would be over-utilized!

I realize that this sounds contradictory to my previous blog where I concluded that I felt comfortable sending my kids to a school where a new cell phone tower is being built. My wife and I remain comfortable with that decision. As written previously, we are happy with our neighborhood elementary school and the good certainly outweighs any risk I might ascribe to radiaton from a cell phone tower (risk that I still believe is very low as further supported by a NYT article from April 13, 2011 - snippets of which I have posted below).

However, when it comes to the weighing of pros and cons in regards to my child carrying a cell phone and using it habitually, not many pros come to mind. Of course safety and better communication are a few positives, but I hope to achieve that with other means and I would not be opposed to a cell phone programmed to only communicate with a set directory.  Of course, as my child matures - both physically and emotionally - I will likely liberalize their phone usage. 

Even if there were no health concerns, there are other issues at stake - sexting, distractions at school, driving and dialing, and over-usage to name a few.  The bottom line is that the health risks seem small and possibly zero. However, there are many reasons to limit the habitual use of a cell phone in a young child and the precautionary principle adds one more reason to the list, but it likely is just that - a precaution.

From the April 13, 2011 NYT. . . here are some excerpts from an excellent article titled "Do Cellphones Cause Brain Cancer" written by Siddhartha Mukherjee who is an assistant professor of medicine in the division of medical oncology at Columbia University. He is the author of “Emperor of All Maladies: A Biography of Cancer.”

The most exquisite — and arguably the most sensitive — means to identify a carcinogen is to study the effects of the substance not on humans or animals but on cells. In the 1970s, a Berkeley biochemist named Bruce Ames devised a cellular test to do just that. Ames’s test is based on a series of simple principles. Normal cells in the body grow through cell division, or mitosis, which is carefully regulated by genes. Certain genes accelerate growth, while other genes dampen or stop it. Cancer originates when the “accelerator” genes are permanently activated or when the “brake” genes are permanently damaged. Since genes are encoded by DNA, chemicals that mutate DNA — mutagens — can alter the growth-controlling genes and thereby cause cancer. Ames devised a special strain of bacterial cells that act as a “sensor” for mutations and therefore can also detect mutagenic chemicals. Chemical mutagens are so commonly carcinogenic that versions of the Ames test represent the gold standard by which most carcinogens are found.

Cellphone radiation is not a chemical, of course, but the rules about mutagenicity still apply (X-rays, for instance, are known to cause cancer and are detectable by Ames’s test). Laboratory experiments that link phone radiation to DNA mutation using a version of the Ames test have been largely contradictory. In 2005, a panel of experts, including a biomedical engineer, an epidemiologist, a genetic toxicologist and a radiation biologist, published a review of nearly 1,700 scientific papers on the cellular effects of radiation emitted by phones. In the review of more than 50 experiments linking phone radiation to DNA damage in animal or bacterial cells, evidence of damage has been negative in more than two-thirds of the studies. Since nonionizing radiation cannot directly affect the structure of DNA, experiments linking phone radiation to DNA damage are generally unconvincing. The most striking study linking cellular phone radiation to DNA damage, published in 2005 by researchers from the Medical University of Vienna, has recently been embroiled in even deeper scientific controversy: researchers studying the data intensively have argued that the original study is fraudulent.

But it is possible for something to be a carcinogen without directly damaging DNA. Some chemicals might activate growth pathways or survival pathways in cancer cells (eventually damaging DNA and mutating genes — but indirectly). Exogenous estrogen, for instance, activates growth pathways in breast cells and can cause breast cancer but doesn’t damage DNA. Others may provoke inflammation, creating a physiological milieu in the body that allows malignant cells to grow and survive. Yet others — the class of substances that we know least about — might not damage DNA directly but chemically modify genes so that their regulation is changed. These substances are like the dark matter of the carcinogenic world: they are barely visible to our current tests for carcinogens and thus lie at the boundaries of the knowable universe. Cellphones and their radiation have been tested for many of these properties — for instance, their ability to chemically modify DNA without causing mutations — but evidence linking this form of radiation to such cellular changes remains largely negative.

This section is about animal studies. . .

Nonetheless, biologists have exposed mice and rats to chronic nonionizing radiation (comparable to that emitted by phones) to determine whether it causes cancer. In rats prone to developing breast cancer, there was no acceleration of breast cancer. In another experiment, rats were treated with a chemical carcinogen in utero (to “prime” them to develop brain tumors) and then exposed to radiant energy comparable to cellphone radiation for two hours per day, four days a week, for 22 months. The experiment revealed no increased incidence of brain tumors in rats. Nor was there any accelerated growth in previously established brain tumors. From 1997 to 2004, six independent experiments on mice and rats studied the effects of chronic radiation on brain cancer. No experiment revealed an increased risk of brain cancer.

An excellent article and if you would like to read it in full here is the link.

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