L. Dworsky Presentation Cellphone safety 092518
A History & Status of Cellular Telephone Health Issues
Lawrence Dworsky Ph.D.
Vice President & Corporate Research Lab Director
Motorola, Inc. (Retired)
Former Director, Electromagnetic Energy Laboratory
Introduction – On the Nature of Statistical Analysis
Suppose we have a study of ten towns, incidence of cancer X:
• National Average = 20 cases per 100,000 people per year (fictional)
• What will our data look like?
20 21 24 17 20 15 27 17 20 19
What is going on in this town? Cancer X Incidence 35% Above Average!
At the outset, we have no idea
• This merits investigation
• There might be a “cancer cluster” cause of some sort
• This might simply be statistical variation and nothing is “going on”
Introduction – On the Nature of Statistical Analysis
What if somebody compared the above data to cell phone usage data,
and they noticed that this town has higher cell phone use than average
This should definitely be investigated, studies repeated, other towns brought in
Keep in mind, however:
1. CORRELATION DOES NOT IMPLY CAUSALITY
2. What if the cancer incidence data was just statistics in the first place?
Take away point: When a study shows positive results:
• This is important to follow up on
• This is NOT a conclusion
• Study has to be repeated, put in perspective in light of many more studies
• In statistics, SHIT HAPPENS.
This actually happened (Italy ~ 1995)
First cell phone tower went up in region
Reporter found childhood leukemia case
nearby
He looked up national incidence rate, calculated that in area around tower containing this case, average rate = 1/6 per year
Leukemia case
Newspaper headline read
AREA NEAR NEW CELL PHONE TOWER HAS 6 TIMES NATIONAL LEUKEMIA RATE
Introduction – On the Nature of Statistical Analysis
Introduction – On the Nature of Statistical Analysis
British Psychic Anecdote
Flawed Study on “Electrosensitivity”
Does everyone know the basics of what a “Cellular Telephone”
Network is, or do we need a brief overview?
Today’s Cell Phone is a very busy little box:
1. Cell phone receiver and transmitter. These talk to the nearest
cell phone tower
2. Blue Tooth receiver and transmitter. These talk to your watch, your
car’s hands-free system, your wireless earphones, etc.
3. WiFi receiver and transmitter. These talk to any nearby WiFi hotspot
4. GPS receiver. This listens to GPS satellite transmissions.
5. Camera and other stuff (level, flashlight, guitar tuner ......)
There are 4 separate antennas
• The proximity of these to your brain when you’re on a call
is the root of the safety concerns
An EM(F) Radiation Primer
All radio, infrared, light, ultraviolet, X-ray, and gamma ray radiation are forms of ElectroMagnetic radiation made up of coupled Electric and Magnetic Fields.
An EM(F) Radiation Primer
From a potential health issue perspective, there are two major categories
1. Ionizing Radiation
2. Non-Ionizing Radiation
The distinction is due to quantum mechanical considerations:
• The energy of a single photon of radiation is proportional to its frequency
• Above a certain frequency (varies a bit with material) a photon carries
enough energy to Ionize an atom – break an electron loose.
• The frequency cutoff is in the deep UV – soft X-ray range.
Why do we care?
An EM(F) Radiation Primer
Ionizing radiation can
• Penetrate solids deeply (it’s hard to stop high energy particles)
• Knock apart atoms
• Precipitate cancers
• Cause genetic mutations
These are considered Non-threshold events:
• The probability of harm is essentially (Amplitude)x(Time)
• Risk is cumulative
• You should drive your exposure amplitude and time towards zero
• If this worries you, why are you living at 6,500 ft?
An EM(F) Radiation Primer
Non-Ionizing radiation cannot
• Penetrate solids deeply without losing most energy
(try getting your WiFi signal through SMA house walls)
• Knock apart atoms
This is considered a threshold event
• Possible harm is related to incident energy amplitude
• Below a certain level, no biological damage occurs
• The accepted “wisdom” is that heating due to energy
dissipation is the cell phone issue
• Boiling Water analogy
• Existing safety regulations are all about keeping heating below a specified level
• The search for possible non-heating issues continues
Pre Cell Phone RF Safety History
Prior to cell phones, the dominant hand-held radios were police radios
High Frequency: About 30 Mhz
Very High Frequency: About 150 MHz
Ultra High Frequency: About 250 MHz
Usable frequencies grew as technology advanced. FCC spectrum allocations
and regulations advanced with technology
In 1973, the FCC opened the first “Microwave” frequencies, about 900 MHz, for radio use. Manufacturers developed products for sale in 1974:
“The Air Is Clear Up Here”
Nobody had any idea about potential RF safety issues or how to find out.
Pre Cell Phone RF Safety History
Motorola was actually a pioneer in this area. (I had nothing to do with it at the time.)
We hired Dr. Quirino Balzano, an RF propagation/bioeffects expert and chartered him to develop a capability and run studies.
Q immediately joined up with neurologists at the U of Miami medical school
(we were in South Florida) and put together a plan:
Pigs’ brains are about the same size and weight as peoples’ brains. They
decided to study pigs.
Motorola bought about 20 pigs and “boarded” them on a (pig) farm in the
Miami area.
Leather neck holsters were built to hold a police-radio next to the pigs’ ears.
Pre Cell Phone RF Safety History
1⁄2 the radios had timers to turn the transmitters on and off
1⁄2 the radios were “controls.” They never came on
This was an “interesting” study:
• Pigs live in mud. Do you want to go change the batteries?
• Pigs got into fights with each other, they’d bite off each
other’s antennas.
(Sometimes research isn’t as glamorous as it’s made out to be)
Pre Cell Phone RF Safety History
After a pre-determined length of time, the pigs were slaughtered (at a
commercial butcher) and the brains were sent off to the medical school
Result: No observable effects.
By today’s standards this whole study is a joke. It was crude and small and
very short.
But: Considering that this was the first serious attempt to look for issues,
it was very significant – and paved the way for future studies.
Q soon started developing (with other groups) what would become
today’s test systems and procedures. (He’s currently on the faculty of the U. of Maryland, still involved with cell phone safety studies and miniature antenna design.)
The Cell Phone Industry
The first cellular system (as we know it) was turned on by NTT in Japan
in 1979. It was an analog system.
The U.S. cellular system (AMPS) turned on in several cities in 1983. This
was primarily an in-car (it took up most of the trunk) system. Early adoption was slow:
• The equipment was expensive
• Calls were expensive
• Coverage was poor and spotty
Motorola introduced the first hand held DYNATAC phone, aka
The Brick, in 1983.
The cell phone industry took off in 1989 when Motorola introduced the MicroTac flip phone and several Japanese manufacturers quickly followed.
The Cell Phone Industry
In the mid-late 1990’s the analog phone was replaced by the digital phone
and the analog system was soon shut down.
Various gadgets such as cameras were added to phones.
Capabilities were added, the SMS service almost happened by accident
The smartphone slowly evolved, with the Apple Iphone in 2007 pretty much defining the product going forward. Concurrent advances in integrated circuits, batteries and displays were both driven by and drove smartphone development. Innovative software, “Apps,” help keep people interested.
There are somewhere between 5 and 7 billion cellphones in the world today. This is about 1 per person, worldwide!
Evolution of Modern Testing
Whether we are ultimately right or wrong about heat being the only health issue, we still need to accurately measure the energy delivered to a user’s brain, both where and how much.
There are two fundamental “problems” which differentiate this from an
ordinary engineering problem:
1. We cannot poke a probe into somebody’s head and ask them to sit still
while we run the cellphone.
2. We cannot ask a group of volunteers to use cellphones in which we keep cranking up the power until we see some detrimental effects.
We can do a lot with computer simulations, but we still need a way to verify / calibrate the simulations.
Evolution of Modern Testing
The system in use around the world today was developed starting in the early 1980s. They are almost all manufactured by APREL, an independent Swiss firm that was founded just to make these test systems. This is probably one over the most “overviewed” companies in the world.
A thin fiberglass mannikin, called
a “phantom” is a hollow structure replicating a human 1⁄2 body.
There are different sized phantoms for men, women, and children.
A liquid was developed which very closely replicates the dielectric parameters of the human brain. This is poured into the phantom. The electric fields in this liquid due to outside (beneath) the phantom radios will closely replicate the electric fields in a human brain due to outside excitation.
Evolution of Modern Testing
Note from electromagnetic field theory: In a dielectric (non-magnetic) material, the ratio of electric:magnetic fields is fixed. If you know one, you know both.
A cell phone is clamped in a fixed location at the head of the phantom. Several specific positions are prescribed by the FCC (in the U.S.)
An electric field probe is robotically moved through the liquid under pre-programmed computer control while the cellphone is run AT FULL POWER.
Evolution of Modern Testing
The probe produces a profile of deposited energy. A computer then calculates the maximum Specific Absorption Rate, which is the average energy deposited over a specified volume (a small cube of specified mass).
The U.S. limit is 1.6 watts/kg averaged over 1 gram of tissue.
The European limit is 2.0 watts/kg averaged over 10 grams tissue
China uses the U.S. standards.
When a cellphone talks to a tower, it cuts back its output power to the lowest level possible to maintain communication. This is done so that the cellphone system can get maximum “spacial reuse” of the towers, i.e. optimize nr of users on the system at once. This means that your cellphone is almost never running at the full power level that the phone’s SAR was measured at.
Also, the modern digital systems are not the old analog Duplex telephone system. The transmitter “carrier” is not on all the time.
After all of this, what have we learned?
There have been hundreds, if not thousands of large scale studies.
These are all Cohort studies – comparing health statistics of cell phone users and how much they use their phones to the same health statistics of non-cell phone users.
The following are excerpted from a 2018 National Cancer Institute report
Interphone
How the study was done: This is the largest health-related case-control study of cell phone use and the risk of head and neck tumors. It was conducted by a consortium of researchers from 13 countries. The data came from questionnaires that were completed by study participants.
What the study showed: Most published analyses from this study have shown no statistically significant increases in brain or central nervous system cancers related to higher amounts of cell phone use. One analysis showed a statistically significant, although modest, increase in the risk of glioma among the small proportion of study participants who spent the most total time on cell phone calls. However, the researchers considered this finding inconclusive because they felt that the amount of use reported by some respondents was unlikely and because the participants who reported lower levels of use appeared to have a slightly reduced risk of brain cancer compared with people who did not use cell phones regularly (5,10,11). Another recent analysis from this study found no relationship between brain tumor locations and regions of the brain that were exposed to the highest level of radiofrequency energy from cell phones (12).
The National Toxicology Program (NTP), a federal interagency program headquartered at the National Institute of Environmental Health Sciences (NIEHS), which is part of the National Institutes of Health (NIH), recently completed a series of large-scale studies in rodents of exposure to radiofrequency energy (the type used in cell phones). This investigation was conducted in highly specialized labs that can specify and control sources of radiation and measure their effects.
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In February 2018, two draft technical reports summarizing the findings were made available in advance of the formal peer-review process in March 2018. Peer review is a critical component of the scientific process to ensure that research findings are meaningful, accurate, and appropriately interpreted.
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The U.S. Food and Drug Administration (FDA) issued a statement on the NTP reports stating they “believe the current safety limits for cell phones are acceptable for protecting the public health.” FDA and the Federal Communications Commission share responsibility for regulating cell phone technologies and FDA originally nominated this topic for study by NTP.
Danish Study
How the study was done: This cohort study, conducted in Denmark, linked billing information from more than 358,000 cell phone subscribers with brain tumor incidence data from the Danish Cancer Registry.
What the study showed: No association was observed between cell phone use and the incidence of glioma, meningioma, or acoustic neuroma, even among people who had been cell phone subscribers for 13 or more years (13–15).
Million Women Study
How the study was done: This prospective cohort study conducted in the United Kingdom used data obtained from questionnaires that were completed by study participants.
What the study showed: Self-reported cell phone use was not associated with an increased risk of glioma, meningioma, or non- central nervous system tumors....
Follow up: What about non-heat related effects?
Despite many attempts, nothing solid has ever been found (personal anecdote here)
There are two comments worth making
1. It’s impossible to prove the negative 2. We should never give up.
My Bottom line: (after Fermi’s comment about extraterrestrials)
Hand held cell phones have been out there for > 30 years
~ 6 billion of them are in use.
If there’s an issue, Where Are All The Sick People?
Epilogue
There have been, over the years, many hundreds of companies, universities
and national laboratories, all over the world, working in this area:
• Singly and in consortia
• Reviewing and repeating other groups’ results as well as producing their own
• Consulting (for example, my group wasn’t the best biological experiment
group but we were one of the best RF test structure designers/evaluators. We were constantly involved in critiquing other groups test setups.)
• It’s impossible to say that there was NO corruption of any sort, but I am personally sure that the overwhelming majority of the groups are ethical, honest and aboveboard.
At Motorola, for example, we got our funding directly from the CTO, not from the radio product groups. Our charter, in writing, from the board or directors, was to guide the company (and the industry) honestly and thoroughly in this area.