The Interphone Study Group report on cell phone safety: Missing the answer by adhering to a flawed principle
As most people know, the safety of cell phones has been a hot topic of debate since several published reports suggested a possible increase in ipsilateral (same-side) brain tumours (malignant gliomas and benign meningiomas) among heavy users.
Although health authorities cautioned that the data from these studies were insufficient to provide a definitive answer, concerned governments from Ontario to India were quick to give advice: children, whose brains might be especially vulnerable to the effects of radiofrequency (RF) emissions, should be discouraged from using cell phones except in an emergency.
Unfortunately, with today’s publication of the highly-awaited Interphone Study Group report, those hoping for that “definitive” answer are certain to be confused. But should they?
This largest-to-date study, conducted between 2000 and 2004, involved 13 countries, including Canada. Carried out under the auspices of the World Health Organization’s International Association for Research on Cancer (IARC), it involved 2708 glioma patients, 2409 meningioma patients, and 2972 carefully matched healthy controls.
The subjects, all between the ages of 30 and 59, were interviewed in person to determine the frequency and cumulative call time (total hours) of cell phone use (or non-use) over several time spans: 1 – 1.9 years; 2 -4 years; 5 – 9 years; 10 or more years.
The findings? As compared to “never-users”, there was an overall 20 to 30% decreased risk of glioma and meningioma tumours in those who used cell phones for 1 -9 years; even after 10 or more years of use, a 2% decreased risk of glioma and a 17% decreased risk of meningioma was found.
When cumulative call time was compared among ever- and never-users, once again a 20 to 30% decreased risk of tumours was observed among users who accumulated less than 1640 hours over 1 to 10 years.
However, once cumulative call times went above 1640 hours for 10 or more years of use (approximately 30 minutes daily), a 15% increase in meningiomas and a 40% increase in gliomas was observed. Perhaps tellingly, the rate of gliomas was a whopping 377% higher in those who accumulated more than 1640 hours over just 1 – 4 years (i.e., ranging from 1.1 – 4.5 hours of daily use). Moreover, as suggested in the earlier studies, their location favored the ipsilateral temporal lobe (the part of the brain closest to the ear).
Yet, despite the study’s findings (both “good” and “bad”), the committee of authors was extremely reluctant to draw any conclusion at all, stating that “[methodological] biases and error prevent a causal interpretation…”. As a result, they called for yet further investigation on “the possible effects of long-term heavy use of mobile phones”, especially among adolescents and teenagers.
The reason is this: they were concerned that an excess of brain tumours was seen only at the highest level of use, with no evidence of a linear increase up to that point. Indeed, except at the highest level of use, there appeared to be a protective effect of cell phones against brain tumours, something the authors dismissed as “implausible”….so implausible that, despite other studies showing a similar trend, the Interphone Study Group is “currently exploring the possibility of correcting the [risk] estimates mathematically”. And with that statement, if any bias exists, it appears to be more in the thinking of the investigators than as a result of the design of the study.
Why? For decades, health officials, toxicologists and regulators, including those associated with the IARC, have only recognized the validity of what is called a “linear (straight line) dose-response” effect. But, based on hundreds upon hundreds of published examples of chemical, hormonal and physical agents, whose dose responses are “hormetic” (derived from the word, hormone, meaning differing effects at low and high levels of exposure), many prominent scientists, chief among them, U. of Massachusetts professor, Dr. Edward Calabrese, believe that the hormetic model, rather than the linear model, may more accurately represent the biological effect, especially at lower levels of exposure, of many agents on human health.
One example is the “J-shaped” curve that applies to alcohol; as compared to non-drinkers, decreased cardiovascular-related mortality is observed in populations that consume up to 2 ounces per day; exceeding that amount results in higher mortality (including cancer) that increases the more one drinks.
Furthermore, although there is evidence of benefit when plants and animals are exposed to low-level terrestrial and extra-terrestrial radiation, the IARC disregards studies of low-dose radiation effects, believing instead that there is no safe lower threshold of human exposure to radiation. That thinking likely extends to RF emissions from cell phones.
So what is the truth about cell phones and the risk of brain tumours? I believe that the answer lies in the hormetic model proposed by Dr. Calabrese and his colleagues. A “J-shaped” dose response (decreased risk of brain tumours with low to moderate use; increased risk with excessive use) is highly consistent with the findings of the Interphone Study Group. Sadly, the “linear thinkers” will say otherwise. Officially, nothing will have been resolved and stiff-necked adherence to a seriously flawed risk model will have obscured highly pertinent findings.
