BioEM2016: The NTP study (part 2/3)

The most anticipated event of the BioEM2016 was the last moment addition of the presentation of the US NIEHS National Toxicology Program study on effects of cell phone radiation in rats and mice. The 8AM Wednesday plenary session was provocatively titled: “Hot Topic Plenary: The US NTP Study: A Real Game Changer or Just Another Study?” and presenters were Myles Capstick of the IT’IS Foundation and Michael Wyde of US NIEHS NTP.

Myles Capstick presented briefly the exposure set up for the NTP study. If anyone wishes to do replication using the same exposure equipment may forget it. The equipment was already dismantled and in some way disposed of. The exposure chambers do not exist anymore. It was too costly to keep them after the exposure of animals was over. Of course, it is necessary to remember that due to rapid technological development over the period of the execution of the NTP-study the chambers, with all associated electronics, become obsolete. Furthermore, the chambers were built for the 2G technology exposures that are vanishing from the consumer market, replaced by the 3G, 4G and soon the 5G.

NTP-study results were presented by Michael Wyde. In essence, Michael presented all that was already known from the NTP Study Draft.

However, there was some additional information of the comet assay summary for rats and mice (table below):

There are numerous misconceptions and misrepresentations of the NTP-study and its outcome. However, one thing is certain, this is the best animal study that can be done with the existing technical and financial limitations. Even with the $25 million funding, scientists can not do all what they would like, and need to do, in order to thoroughly address all issues and answer all questions.

First of all, this was and will be an important study: “This is by far—far and away—the most carefully done cell phone bioassay, a biological assessment. This is a classic study that is done for trying to understand cancers in humans. There will have to be a lot of work after this to assess if it causes problems in humans, but the fact that you can do it in rats will be a big issue. It actually has me concerned, and I’m an expert.” said Christopher Portier, a retired head of the NTP who helped launch the study. Portier also commented “The NTP does the best animal bioassays in the word. Their reputation is stellar. So if they are telling us this was positive in this study, that’s a concern.”

There are complaints that the radiation dose was very high and exposed was the whole body. To this, we need to remember that this is toxicology research. In such studies, on purpose, animals are exposed to very high doses of tested compounds. Doses so high that human will never encounter such exposures in real life. This is the way to determine whether tested compound causes health problems to animals and if it does, it means that it is possible that also human health might be affected. It does not prove that human health will be affected in the same way, but it shows that the possibility exist and that humans should be careful.

The very high doses of cell phone radiation used in the NTP study came from tests performed before the actual 2-year test begun (5 day pilot study and 28 day pre-chronic toxicology study). Tests looked for the highest possible dose that will be tolerated by the animals. Even the highest of the selected doses were shown, by testing, to be tolerated by the animals – not increasing the body temperature more than the ICNIRP’s recommended 1^oC.

The other concern was that the animals received the whole body exposure, unlike humans who get predominantly head exposure. Doing head only exposures would require, as in some previous studies, Ferris wheel type set-up. This would involve lots of handling of the animals by the personnel and would limit time available for exposures. Housing animals free in cages allowed longer exposures (up to 9 hours/day) and less stress caused by the handling of animals (no frequent putting in and removing as it is with the Ferris wheel).

Of course, freely moving animals in cages experienced stress too – animals were single housed what is stressful (social stress of lifetime living alone) for the animals normally living in packs, like rats or mice do.

Another misunderstood issue is the transfer of knowledge gained with animals to humans. We cannot perform experiments on humans. Information obtained from animal studies is not directly transferable to human situation. However, animal studies have no such purpose – to provide information directly applicable to human health. Animal studies provide information whether health of complex living organism is affected by the examined agent. Such information is then used, in combination with epidemiological studies and laboratory in vitro studies, to determine human health risk. Animal studies are not used in vacuum. They are used as a supportive evidence.

Therefore, the outcome of the NTP study should be considered in the context of the to-date performed epidemiological, animal and in vitro studies. The combination of all the elements suggests that cell phone radiation possibly (or probably) affects human health because:

• three case-control epidemiological studies (Interphone, Hardell’s group, CERENAT) have shown increased risk of developing glioma in avid, long-term users of cell phone (30 min/day for 10+ years)
• animal studies, show increased health risk in exposed or co-exposed animals (e.g. Chou et al., Tillman et al, Lerchl’s group, NTP-study)

Lack of the mechanism does not preclude that the event happens. In context of the recent study by Schmid & Kuster, showing that the cell culture experiments were under-exposing cells to radiation, it is possible that the majority of the in vitro studies shows low or lack of effects because of this under-exposing to radiation. Higher doses, as suggested by Schmid & Kuster, would certainly lead to more robust in vitro effects. Replication of some of the in vitro experiments with higher exposures might turn on some evidence of mechanism(s).

Cohort epidemiological (Danish Cohort and Million Women) studies are of poor quality and cannot be used as a reliable proof of no effect.

In conclusion, we still do not have the definite proof that cell phone radiation causes cancer or increases risk of developing brain cancer. However, combination of the evidence from the case-control and from the animal studies indicates that the health risk is possible or even probable. The NTP study strengthens this “probable health risk” evidence.

This conclusion strengthens the call for the implementation of the Precautionary Principle in the area of cell phones and human health risk. It seems that the human health risk might not only be possible but it might rather be probable, in language of the IARC cell phone radiation could be upgraded from group 2B to group 2A.