Get Off The Phone? New Saliva Study Suggests Possible Cancer Link

Here’s something else to worry about today:

Researchers out of Tel Aviv, studying the saliva of 20 heavy cell phone users (on average 29 hours a month on the phone for 12 years) find troubling signs: “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…”

A WHO agency cities a possible link between brain cancer and cell phone use

A WHO agency cities a possible link between brain cancer and cell phone use

Researchers report a “significant increase in all salivary oxidative stress indices studied in mobile phone users. Salivary flow, total protein, albumin, and amylase activity were decreased in mobile phone users. These observations lead to the hypothesis that the use of mobile phones may cause oxidative stress and modify salivary function.”

Back in 2011, there was big news from the WHO when cell phones were categorized as possibly carcinogenic to humans by the International Agency for Research on Cancer. It was the first time a World Health Organization agency made the claim but still no study has been conclusive. “There is some evidence for an increased risk of glioma,” or brain cancer, Kurt Straif, head of the IARC Monographs Program back when the news came out. “It’s not at the moment clearly established that the use of mobile phones does in fact cause cancer.

But more reports — and more complex and sometimes contradictory evidence — continues to dribble in.

Here’s more from the news release on the Israeli saliva study, published in the Journal Antioxidants and Redox Signaling:

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…

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.

I’m just glad my kids don’t talk on the phone much anymore — they just text. Readers, haw do you manage the potential health dangers of cell phones?

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  • MikeInMass

    Did they compare against people who use non-cellular phones frequently? Perhaps heavy voice usage of any phone could reduce salivary flow, etc.?

    • BostonDad

      Indeed, they used “a control group, which consisted of deaf patients” who presumably may speak less, using sign language or e-readers, doesn’t sound like the right controls at all. They should have used age-matched, sex-matched, controls who use minimally or not at all, IF such people exist !

      • MikeInMass

        Furthermore, they called “heavy” users those who talk more than 8 hours a month (about 15 min/day), which I thought was frighteningly low to show an effect, but with an average of an hour a day, which makes me wonder about the spread. But they seemed to have counteracted the effects this variation by using a huge sample size (n=20). Admittedly, I’m just pulling info from this report on the paper, which I haven’t read, nor do I seem inclined to do.

        • BostonDad

          Right !
          Plus Framingham Heart Study and the like use huge numbers, 1000s. 20 is a non-placebo purely toxicity-sized Phase 1 size, not a strong statistical survey. Hard to control for all other variables unless 100s.

          • MikeInMass

            I’ve seen published studies with n=3. The problem with quoting small studies is that the results may be from normal statistical variation, but their results are treated by the casual reader as equivalent to those from huge, well-controlled studies. Then the ensuing confusion makes the good scientific studies (in general, on any subject) seem less credible in the eyes of the general public.

          • BostonDad

            too true !

  • Zoup

    Without a plausible mechanism for the non-ionizing radiation of cell phones to cause oxidative damage and the like, it is very unlikely that the correlation between cell phone use and cancer is also a causal relationship. Instead there is likely some third variable that is at play. People who talk on cell phones heavily are probably very busy, and hence stressed out, and constant stress is generally linked to a number of negative health outcomes, including cancer.

    Even if this study controlled for the possibility of a third variable, its conclusion is still fairly weak. Given the inconclusive nature of the already existing literature, this study hardly does anything to make it more probably that talking on a cell phone causes cancer.