Interphone results: are we any closer to the truth about cell phones and brain tumors?

June 3, 2010 by  
Filed under CANCER

Last month, the US FDA issued a consumer update on the health risks of cell phone use based on the latest Interphone International Study Group results. The Interphone studies were initiated in 2000 in 13 countries mainly in Europe (US is not included), coordinated by the International Agency for Research on Cancer  (IARC) of the World Health Organization (WHO). The Interphone studies are led by 21 international scientists. The latest results are now posted online in the June issue of the International Journal of Epidemiology.

The main message of the FDA update: Mobile phone use does not cause brain cancer.

The Study

The study looked at a very large number of phone users (about 13,000) using cell phones for at least 10 years and focused on 4 types of tumors in the area of the brain most likely exposed to radiofrequency (RF) during phone use. These tumors are glioma, meningioma, tumors of the acoustic nerve, and of the parotid gland.

Some of the data suggested that heavy phone users may be at risk but after adjusting for biases and errors, the authors conclude: “There is little or no risk of brain tumors for most long-term users of cell phones.”

According to Abiy Desta, network leader for science at FDA’s Center for Devices and Radiological Health:

“There are still questions on the effect of long-term exposure to radio frequency energy that are not fully answered by Interphone. However, this study provides information that will be of great value in assessing the safety of cell phone use.”

Does the latest report settle the question of the link between mobile phone and cancer? Let us look at what people have to say

Who’s happy with the results?

Aside from the FDA and WHO, not many agencies were satisfied with the Interphone results. The mobile phone industry, who contributes substantial funds to the Interphone study, is of course pleased about the results. The GSM Association in the UK states:

“…the large body of existing research and many expert reviews that consistently conclude that there is no established health risk.”

Who’s not satisfied with the results?

WHO study has no clear answer on phones and cancer
This report from Reuters said that the Interphone results “gave no clear answers.”

Even some Interphone scientists believe that their results are inconclusive.

According to on Interphone scientist Elisabeth Cardis of the Center for Research in Environmental Epidemiology in Barcelona, Spain:

“We can’t just conclude that there is no effect. There are indications of a possible increase. We’re not sure that it is correct. It could be due to bias, but the indications are sufficiently strong… to be concerned.”

The director of the IARC tells Reuters:

“The results really don’t allow us to conclude that there is any risk associated with mobile phone use, but… it is also premature to say that there is no risk associated with it.”

No answer, just fuzz, from cell phone study
This msnbc report, too, says that the results are inconclusive. The article quoted epidemiologist Jack Siemiatycki of the University of Montreal Hospital Research Centre in Canada as saying that the results are “ambiguous, surprising and puzzling.”

There are a lot of criticisms about how the studies were done, mainly the so-called “recall bias” of retrospective studies. The quality of the data is in question as there is a tendency for heavy users to overestimate their phone use and light users to underestimate theirs.

According to Mireille Toledano, an epidemiologist at Imperial College London:

“The problem with mobile phones is that when you’re trying to do a retrospective study like this, you’re almost totally dependent on people recalling. You haven’t got anything else on which to base your data.”

What now?

In science, the standard practice is when in doubt, look again. This is exactly what is going on. In the planning is an even larger study (a quarter of a million people!), but a prospective one (“forward-looking”) which will follow up users regularly for a period of time, to remove the “recall” bias. The problem with prospective studies is that they take time, e.g. for this kind of epidemiological study, 10 years might be too short to get clear results. We might have to wait for another 30 years. In the meantime, mobile telephony is evolving fast.

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NOTE: The contents in this blog are for informational purposes only, and should not be construed as medical advice, diagnosis, treatment or a substitute for professional care. Always seek the advice of your physician or other qualified health professional before making changes to any existing treatment or program. Some of the information presented in this blog may already be out of date.