I have been taking some time off. I was not planning on posting again until mid next week, but this recent news story is so hideous, it was impossible for me to ignore it. Recently a study was published which claims to have found marked differences in the saliva of heavy cell phone users. This would be significant, if it were true, because it could show a direct biological effect on the saliva glands and, by extension, the possibility that this could lead to cancer or another condition.
It has been making the rounds in the mainstream media, as one might expect. These kind of studies are almost guaranteed to generate a lot of press.
Heavy Cell Phone Use Linked to Oxidative Stress
July 29, 2013 — Scientists have long been worried about the possible harmful effects of regular cellular phone use, but studies so far have been largely inconclusive. Currently, radiofrequency electromagnetic fields, such as those produced by cell phones, are classified as possibly carcinogenic to humans (Group 2B) by the International Agency for Research on Cancer (IARC). A new Tel Aviv University study, though, may bring bad news.
To further explore the relationship between cancer rates and cell phone use, Dr. Yaniv Hamzany of Tel Aviv University’s Sackler Faculty of Medicine and the Otolaryngology Head and Neck Surgery Department at the Rabin Medical Center, looked for clues in the saliva of cell phone users. Since the cell phone is placed close to the salivary gland when in use, he and his fellow researchers, including departmental colleagues Profs. Raphael Feinmesser, Thomas Shpitzer and Dr. Gideon Bahar and Prof. Rafi Nagler and Dr. Moshe Gavish of the Technion in Haifa, hypothesized that salivary content could reveal whether there was a connection to developing cancer.
Comparing heavy mobile phone users to non-users, they found that the saliva of heavy users showed indications of higher oxidative stress — a process that damages all aspects of a human cell, including DNA — through the development of toxic peroxide and free radicals. More importantly, it is considered a major risk factor for cancer.
The findings have been reported in the journal Antioxidants and Redox Signaling.
For the study, the researchers examined the saliva content of 20 heavy-user patients, defined as speaking on their phones for a minimum of eight hours a month. Most participants speak much more, Dr. Hamzany says, as much as 30 to 40 hours a month. Their salivary content was compared to that of a control group, which consisted of deaf patients who either do not use a cell phone, or use the device exclusively for sending text messages and other non-verbal functions.
Compared to the control group, the heavy cell phone users had a significant increase in all salivary oxidative stress measurements studied.
“This suggests that there is considerable oxidative stress on the tissue and glands which are close to the cell phone when in use,” he says. The damage caused by oxidative stress is linked to cellular and genetic mutations which cause the development of tumors.
The fact that this was even published leads me to believe that the journal in question must have extremely poor standards for peer review.
The number of study subjects is pretty small, and that itself would call into question any findings. However, I will not bother critiquing the statistical distribution or significance of the study, because none of that actually matters, and doing so would dignify the validity of the study’s methods. In fact, regardless of how dramatic and significant the findings of such a study are, they are irrelevant to the debate on mobile phones and health because of a massive foundational flaw in the study.
When conducting a study of this type, it’s important to have a good demographic match between the study group and the control group. The two groups should be as close as possible in terms of age, gender, ethnicity, background and so on. Otherwise, the subjects should be randomly selected. This assures that the only thing different between the two groups is the variable being studied. In this case, that would be mobile phone usage.
Therefore, to conduct a study on mobile phone usage, you would want two groups that are very similar but where one group consists of heavy phone users and the other of those who rarely or never use a mobile phone. That’s getting increasingly difficult in this day and age, but it should still be possible to find those who do not use mobile phones at all, and therefore would have to simply compare very heavy users to those who only use their phone for talking occasionally. This, of course, could be verified through billing data.
The authors of this study instead chose to use deaf individuals for their control group. Although this does offer a population sample that would not be using mobile phones, it is such a poor demographic match, it undermines any conclusion of the study. In effect, the study simply shows that there is an apparent difference in salivary oxidative stress between deaf and non-deaf individuals.
This is hardly a groundbreaking discovery. The demographics between deaf and non-deaf members of the population are pretty obvious. Deaf people are not likely to be involved in certain jobs, such as those which include a lot of direct contact with the public. They would be more likely to work in closed environments, where direct communications with the general population is not a requirement. Deaf individuals are likely to have attended special schools and socialize in more closed groups. They certainly would not be frequent patrons of concerts or other events where hearing is important. Also, since deafness can be caused by any number of medical, environmental or congenital conditions, it would be expected that a history of certain medical conditions would be especially high in the deaf community.
But above all else, deaf persons generally do not talk. Of course, some deaf people do have the ability to speak, having been taught to produce speech sounds, even without the ability to hear them. However, such individuals still are not likely to speak anywhere near as much as those who are not deaf and would have learned how to speak much later in life. On the other hand, those who can hear, speak all the time without much thought. This is hugely important, because the act of talking stimulates saliva production. It also forces a person to breathe through their mouth, resulting in more moisture evaporating and the potential for a dryer mouth.
Since speaking has such direct and obvious effects on a person’s mouth and saliva glands, it is absolutely ridiculous to consider a group of deaf and non-deaf persons to be an even remotely good demographic match for something like saliva tests.
This entry was posted on Thursday, August 1st, 2013 at 10:49 am and is filed under Bad Science, inverse square, Not Even Wrong, Obfuscation. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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