A VERY HIGH BAR
Epidemiology has always faced the same dilemma. It is a science of measuring associations, but people want it to measure causation. Proving that one thing causes another is extremely difficult, even when causation seems obvious. It is easy to show that plant growth and sun exposure are associated. But try to prove that sunlight causes plants to grow. That is a trickier matter.
Of course, the problem of determining cause and effect casts a broad net; it affects more than epidemiology specifically, or even health science in general. But it is a particular dilemma for the field of public health, because it’s very hard to solve a health problem when you don’t know what’s causing it. The infectious disease scientists took the first serious crack at solving the causation problem, and the best they could come up with was a list of criteria that, when met, strongly supported the causation of an illness by a particular suspect infectious agent. These criteria, known as Koch’s postulates, were developed by Robert Koch (1843–1910) in 1884 to help identify the microorganisms that cause tuberculosis, cholera, and anthrax, and have been used by scientists to identify the causes of infectious disease ever since. More recently, Koch’s postulates were employed to establish that a particular virus, now known as human immunodeficiency virus (HIV), actually causes the disease AIDS—a contention originally doubted by many.
In 1965, Austin Bradford Hill (1897–1991), a prominent British epidemiologist, developed a set of criteria that could be used to make the case for disease causation by an environmental agent, similar to how Koch’s postulates are used for infectious agents.9 There are a total of nine Hill’s criteria of causation, and only rarely are all nine met. It is generally accepted, though, that the more criteria met, the stronger the evidence for causation. We cannot review all the criteria here, but the first five are considered the most important and are the most relevant to cell phones and cancer. These are (1) the magnitude of association should be large; (2) the association should show consistency across studies; (3) there should be temporality, meaning that the exposure should precede the disease by a reasonable length of time; (4) there should be a coherence of explanation or, in other words, it should not contradict other known facts; and (5) there should be a dose-response relationship.
When epidemiology studies fulfill these five criteria, the case becomes very strong that the suspect environmental agent causes the disease. In the case of cell phones, we aren’t even close to fulfilling the first five of Hill’s criteria:
1. The magnitude of the association between cell phone and cancer is not large. The alleged 40% increase in risk is a relatively weak association. For example, the association between smoking and lung cancer is on the order of a 2,000% increase.10
2. The association between cell phones and cancer is not consistent between studies. Sometimes there is increased risk, sometimes no risk, and sometimes even protection.
3. Temporality is often taken to mean simply that the exposure must precede the disease, a requirement that seems intuitively obvious. But, actually, its definition can be extended to mean that the appearance of the disease must be sufficiently delayed after exposure to be consistent with its known latency period. For cancers, latencies are at least five years. In the case of the INTERPHONE study, the alleged association between cell phone use and cancer doesn’t appear until after seven years of exposure, so this would be consistent with the temporality criterion. However, temporality has never been explicitly investigated, and individuals with tumors that are deemed to have arrived too early are often just dropped from the studies.
4. Radio waves are a type of nonionizing radiation. As we’ve learned, nonionizing radiations do not have sufficient energy to break chemical bonds, which is the means by which DNA is damaged. The most they can do is produce heat. That is why the chief health concern for nonionizing radiations, such as microwaves, radar, or radio waves is burns from excessive heating. The prospect that nonionizing radio waves might cause cancer like x-rays, gamma rays, neutrons, alpha particles, and other ionizing radiations do, is counter to the known mechanism by which environmental agents cause cancer (i.e., by damaging cellular DNA). Radio waves from cell phones are too weak to cause even heat damage, let alone break chemical bonds. (Videos on the Internet allegedly showing cell phones cooking eggs are bogus.) Random reports that claim radio waves can damage DNA have not been reproducible and are, therefore, not considered credible.11 If radio waves cause cancer, it would have to be through their own unique and unknown mechanism that somehow does not involve any damage to DNA. Is that within the realm of possibility? Of course it is. But if it’s true, it would cause a complete paradigm shift away from everything we have learned about environmental carcinogenesis since 1915, when scientists Koichi Ichikawa and Katsusaburo Yamagiwa of Hokkaido University, in Japan, first started painting coal tar on rabbit ears to explore why chimney sweeps got scrotal cancer; this is the research that ultimately led to the discovery that chimney soot contains DNA-damaging chemicals.12 In short, we have no coherent explanation of how radio waves might cause cancer that would be consistent with our 100 years of evidence that DNA is the target for carcinogenesis.
5. There is no clear dose-response relationship. In fact, the very study that defines a 40% increase as the high-end risk also suggests 20% protection at lower doses. In order for us to accept that this represents a true dose-response relationship, we would also have to accept that small doses of radio waves are actually beneficial to health, a contention that almost no one is willing to adopt at this point.13
It’s clear that cell phones fail miserably as a cause for cancer based on the Hill’s criteria. Does that mean it is impossible for cell phones to cause cancer? No. It simply means that cell phones don’t meet even the minimum conditions that we would expect to see in epidemiology studies, if it were true.
In short, epidemiology alone can never prove causation, it can just make a very strong case that an environmental agent causes a particular disease. Using Hill’s criteria, the case for cell phones causing cancer is extremely weak, suggesting that they do not cause cancer. But if you think showing causation is difficult, it’s nothing compared to trying to prove that something does not cause disease. Few scientists would even try. It’s noble to take on challenging tasks, but foolish to attempt the impossible.
INNOCENT BEYOND A REASONABLE DOUBT
The problem with the IARC classification system for potential carcinogens is that complete exoneration is not possible. How can anyone say with certitude that it is impossible for some particular environmental agent to cause cancer? That’s an unreasonable standard to meet. In fact, the IARC carcinogen categories don’t even allow for that. The best a compound can do is to be designated as “probably not carcinogenic to humans” (group 4), and only one agent out of 970 evaluated in the history of IARC panels has gotten that designation. Caprolactam, a chemical used in the manufacture of nylon, is the sole agent that has made it into group 4.
There are actually five possible groups for a potential carcinogen to be assigned to under the IARC classification system:
Group 1
Carcinogenic to humans
(113 agents)
Group 2A
Probably carcinogenic to humans
(66 agents)
Group 2B
Possibly carcinogenic to humans
(285 agents)
Group 3
Not classifiable as to its carcinogenicity
(505 agents)
Group 4
Probably not carcinogenic to humans
(1 agent)
In contrast to lonely caprolactam, the newly assigned radio waves have a lot of company in their category (group 2B) of “possibly carcinogenic to humans.” The 285 agents in group 2B include aloe vera leaf extract, coffee, gasoline engine exhaust, talcum powder, pickled vegetables, and even the profession of carpentry. Just about every individual is exposed to one of these agents, and they are just as culpable of being a cancer-causing agent as ra
dio waves.
The point is this: The news about radio waves should not have been that they were listed as “possibly carcinogenic” (group 2B). Rather, the news should have been that they were not listed as carcinogenic (group 1) or even “probably carcinogenic” (group 2A).14
WEIGHT OF EVIDENCE
The only thing more controversial than the risks of cell phones are the benefits. Cell phones are both glorified and demonized. Few people would dispute that a cell phone is extremely useful for calling in assistance when your car slides off an icy road and into a marsh, as Mr. Day worries about. But the value of talking on the phone about weekend parties while driving to high school, not so much. We’ll leave it to you to assign a value to your cell phone.
On the risk side, you can choose to accept the contention that cell phones cause cancer and go with the worst-case estimate of a 40% increase in brain cancer risk, making the NNH for cell phones equal to 420. If you decide adopting this worst-case scenario is the most reasonable approach, then just ponder that number (420) for a while and decide for yourself whether this level of cancer risk is worth the benefit to you.
But the beauty of cell phones is that the means to control your personal risk is literally in the palm of your hand. If you’re uncomfortable with this risk level, you can virtually eliminate your risk while still retaining the benefits. As we’ve already mentioned, it’s the phones themselves and not the cell phone towers that are giving us the dose, and it’s our heads that are taking the brunt of it. Fortunately, cell phones can be used with headsets as an alternative to holding the phone next to our head. By using headsets, the dose to the head can be reduced to nearly nothing, and if the cell phone isn’t consistently pressed against some other part of the body the rest of your organs are spared too. Even using hands-free Bluetooth audio devices will largely eliminate the alleged threat because Bluetooth signals are notably weaker than the cell phone signals themselves. So just use headphones or Bluetooth and keep talking on your cell phone without worrying about cancer.
Alternatively, you can decide that there is little credible evidence that cell phones cause cancer, keep your cell phone, and move on to worrying about some of your other exposures, where evidence of an adverse health effects is well established. Either way, don’t wait to make a decision until definitive proof of cell phone safety comes along, because that day will never come. It’s your call, and there is no sense in waiting to decide. You might as well make a decision today. Science will never be able to guarantee safety. To quote Clint Eastwood, “If you want a guarantee, buy a toaster.”
CIRCUMSTANTIAL EVIDENCE: NEUROLOGICAL SYMPTOMS
There is a small group of people who complain that radio waves produce headaches and other neurological symptoms, apart from any cancer they might cause. They claim to have a condition called idiopathic environmental intolerance to electromagnetic fields, or IEI-EMF. The medical community does not recognize IEI-EMF as a legitimate disease and suggests that the symptoms, if real, are either due to another cause or are psychosomatic in origin. Regardless, some of these people have sought complete refuge from radio waves by immigrating into the small town of Green Bank, West Virginia, where they claim to find relief. This town is in the National Radio Quiet Zone, an area of about 13,000 square miles (34,000 square kilometers) in a very rural and mountainous region straddling the Virginia and West Virginia border.15 Personal cell phones and any other devices that transmit radio waves are banned in the Quiet Zone because they cause background noise at the National Radio Astronomy Observatory in Green Bank, which houses a radio telescope that measures low-level radio-wave radiation emanating from deep space.16
The Quiet Zone has been in existence since 1958. Longtime residents claim not to miss cell phones because they have never known them, and they like the fact that the technological constraints of the Quiet Zone help ensure the area will remain rural. The IEI-EMF sufferers say living in Green Bank has provided them relief from their radio wave-induced symptoms and are happy to trade modern wireless conveniences for good health.
Unfortunately, IEI-EMF, if it does truly exist, must be classified as an orphan disease because not enough people suffer from it to attract the attention of the medical community. There have been seven double-blind clinical trials, but they have all been negative, meaning no association between radio waves and symptoms was found.17 Double-blind studies are to clinical trials what cohort studies are to population epidemiology. They are the gold standard for proving the existence of a clinical condition or a treatment effect. In a double-blind study, everything is concealed from the patients as well as their doctors—so both are “blinded” as to who’s getting the real treatment and who’s getting the placebo. This prevents any biases from being introduced. The code is cracked on the data only at the end of the study, at which point the treatment’s test and placebo patients are identified and the results analyzed.
Since the double-blind studies failed to validate IEI-EMF, implying no association between the claimed neurological symptoms and radio waves, can we rule out that radio waves cause neurological symptoms? Just as we’ve seen for cancer, we cannot. We cannot dismiss causation simply because we lack any evidence for it. All we can say regarding the potential of cell phones to cause IEI-EMF is that there is a complete lack of any high-quality clinical evidence to support it, leaving only anecdotal testimonies and unreliable non-blinded studies as the alleged proof of its existence. Again, Hill’s criteria of causation are not met. But in terms of coherence (criterion 4), perhaps there is a better case to be made for radio waves causing IEI-EMF than cancer.
In contrast to cancer, where DNA damage would presumably be a requirement for causation, the notion that neurological symptoms could be caused by radio waves seems more tenable, and more coherent, with the known mechanism of the nervous system. The human brain is the center of a complex network of neurons that transmits and receives electrical signals throughout the body, and radio waves can interact with electrical systems. Are radio waves interfering with the neuronal circuitry of the bodies of these people? If so, what is unique about their bodies that they should be so highly predisposed to symptoms when the vast majority of us is not affected?
These questions may never be answered. There are too few people claiming to be affected to warrant large-scale studies, and there is no current evidence that their alleged symptoms are real. A cancer is a cancer, and cancers are definitely not psychosomatic. But a headache or other pain is a self-reported symptom that is hard to document or authenticate. Until some quantifiable neurophysiological endpoint surfaces that scientists can measure and validate independent of the self-reported complaints of the patients, it is unlikely that IEI-EMF will get any serious attention from the medical community. This means that, for IEI-EMF suffers, permanent residence in Green Bank will likely remain their only option for relief.
SEX OFFENSE: INFERTILITY
There is one other frequent question about cell phones that seems to reflect widespread concern: Can cell phones carried in pants pockets cause infertility? Ever since male soldiers started telling their female companions that radar duty had rendered them sterile, the false rumor that radio waves produce male infertility has persisted. Hermann Muller directly addressed the question in his fruit fly model in the 1940s and found no credibility to it.18 Atomic bomb studies and experiments with animals tell us that large numbers of spermatogonia cells—the cells that give rise to sperm—must be killed in order to produce infertility, and even then the condition is typically temporary. Radio waves do not kill cells, so the contention that radio waves produce infertility doesn’t seem plausible. And sporadic reports that radio waves do induce infertility have not been reproduced or validated. Whether this alleged infertility should be considered a risk or a benefit of cell phones all depends upon your perspective. But an unplanned pregnancy cannot be blamed on a dead cell phone battery.
CHAPTER 15
HOT TUNA: RADIOACTIVITY IN FOOD
According to the Glob
al Research Report, recent tests in California have unearthed contaminated bluefin tuna in nearby coastal waters. … In addition, the cesium-137 level has also gone up along the California, Oregon and Washington coasts. … In Alaska, the sockeye salmon population has declined apparently due to radionuclides as well.
—Marisa Corley (reporter for Liberty Voice)
Do not tell fish stories where the people know you; but particularly, don’t tell them where they know fish.
—Mark Twain
ON THE RIGHT TRACK
Daniel Madigan is a recreational angler and a professional marine biologist. Fish intrigue him, particularly the big ones, like marlin, sailfish, and tuna. “It’s black water, and all of a sudden you have this huge animal,” he exclaims. He thinks such encounters with these enormous pelagic fish in the open ocean are enchanted moments, and they make him wonder: “Why now, and why here?”1
These giants of the sea lead mysterious lives that include migrations of thousands of miles, but the details of their migratory journeys are poorly understood. Madigan hopes to change that. He did his doctoral studies at the Hopkins Marine Station of Stanford University, a place where migratory behavior is studied for a number of ocean species, including great white sharks, leatherback turtles, black-footed albatross, and bluefin tuna. Most of this tracking is done with electronic transmitters that require individual animals to be captured, tagged, and released unharmed. No easy task, particularly when the animals are very large.
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