ornitz@kodak.UUCP (barry ornitz) (01/05/88)
In yesterday's newspaper, I noticed with great interest an article entitled
"Link suggested between cancer, electromagnetic fields."
The article had the byline of the Associated Press, Tacoma, WA. It was
stated in the article that "amateur radio operators in two states appear to
die at abnormally high rates from several forms of cancer, suggesting a
possible link between cancer and electromagnetic fields, according to data
collected by a state epidemiologist." This article appears to be prompted
by work published in the American Journal of Epidemiology by Dr. Samuel
Milham Jr. of the Washington Department of Social and Health Services.
According to the article, Dr. Milham studied the deaths of 2,485 Washington
and California amateur (ham) radio operators between 1979 and 1984. Based
on a population this size, he found the following data:
Expected Actual
Cause Deaths Deaths
--------------------------------------------------------------------------
Leukemia 29 36
Lymphatic & Blood Forming
Organ Cancers 72 89
Prostate Cancer 67.6 (!) 78
I am not sure about the statistical differences between these numbers, but
I am certain that a trained epidemiologist would check the statistical
significance of his data before publishing. Dr. Milham is further reported
to have concluded that "amateur radio operator licensees in Washington
state and California have significant excess mortality due to acute myloid
leukemia, multiple myeloma and perhaps certain types of malignant
lymphoma."
The Associated Press article also quoted Leonard Sagan, program manager for
radiation studies at the Electric Power Research Institute in Palo Alto,
CA. Sagan warned that studies like Dr. Milham's could be misinterpreted,
and that the "findings could be simple associations that have nothing to do
with cancer causes among people who work with electricity."
Having been an amateur radio operator for over twenty-three years, and
having been concerned with the safety of exposure to non-ionizing, radio
frequency electromagnetic energy as a small portion of my job, I have a few
comments about this article. Before I begin, I should state that my title
of Dr. is not a medical one, but rather a PhD in Engineering. I should
also state that I have not yet read the article in the American Journal of
Epidemiology.
The medical effects of exposure to electromagnetic radiation have been
shown to be frequency dependent. This is logical since as the wavelength
of radiation approaches the dimensions of the human body, absorption of the
radiation is enhanced due to more efficient coupling into the body. At
higher frequencies (shorter wavelengths), typically in the microwave
region, the electromagnetic radiation is absorbed near the surface of the
body. The ANSI standards for exposure to radio frequency energy take this
information into account, placing the most strict requirements on
frequencies in the VHF (very high frequency) region. Amateur use of the VHF
spectrum, while dating back over fifty years, has primarily been negligible
until twenty years ago. Amateur transmitter power levels in the VHF region
have generally been much lower than the power levels used in the high
frequency bands. Antenna placement for VHF, in terms of wavelengths from
the amateur's operating position, is generally high. These three facts
would tend to cancel the increased hazard of VHF radiation. To test
Milham's hypothesis further, a study of FM broadcast engineers, commercial
two-way radio technicians, and television transmitter engineers should be
performed since these persons are all exposed to various levels of VHF
radiation. The highest field strengths to which amateur radio operators
are normally exposed come from the near field antenna radiation during high
frequency operation. Power levels of up to two kilowatts may be used with
antenna placement often below a wavelength. It should be noted that
exposure to this power level is intermittent in most amateur operation. If
Milham's hypothesis is correct, broadcast technicians and engineers for
commercial AM and especially short wave broadcast stations, as well as
military communication operators should show even higher levels of cancer
deaths than hams. Operation on microwave frequencies by amateur radio
operators is rare; furthermore, I would expect any cancers caused by
microwaves to be other than deep tissue cancers. A study of the eyes for
cataracts would be in order, too, since microwave exposure generally causes
eye problems prior to additional damage in the human body.
I believe that other causality should be investigated by the medical
profession before Dr. Milham's conclusions are accepted. I would expect
that the amateurs studied by Dr. Milham were mostly individuals who had
been hams for many years. An analysis including the length of time that
the amateurs were licensed (or at least active) would be in order. I
believe that this analysis would show some increased mortality (adjusted
for age, of course) for the older hams. If this increased mortality
exists, I feel that other environmental factors should be studied in
addition to exposure to electromagnetic fields.
Until twenty-five to thirty years ago, much of the amateur radio equipment
in use was home constructed. The construction of electronic equipment at
this and especially prior years, exposed the amateur to a number of
chemical hazards, many of which were not known as hazards at the time. For
example, I would expect to see higher than normal levels of metals in older
hams such as tin, lead, bismuth, antimony, and cadmium (from soldering);
mercury (from broken rectifier tubes and relays); barium, beryllium, and
rare earth oxides (from broken vacuum tubes and phosphors from cathode ray
tubes); radium (from luminescent dials); selenium (from rectifiers); and
manganese and zinc (from batteries). Likewise these hams would have been
exposed to rosin fumes containing numerous organic acids (from soldering),
paint solvents and cleaning fluids such as benzene and carbon
tetrachloride, phenol (from burnt phenolic insulators), and asbestos. Even
more insidious, however, was the exposure to transformer and capacitor
impregnating oils. These oils often contained poly-chlorinated biphenyls
(PCB's) as flame retardants, sometimes in quite high concentrations.
These chemical hazards were not unique to amateur radio operators only.
Other electronic hobbyists as well as people manufacturing electronic
equipment would have been exposed to similar hazards. I feel that it would
be prudent to compare mortality rates of workers in oil-filled capacitor
manufacturing plants to those of the hams studied [for example, the Sangamo
capacitor plant in Pickens, SC, which until several years ago was a major
user of PCB oils].
In conclusion, I believe that other causal relationships between cancer
deaths and amateur radio operators may more adequately explain Milham's
data. I propose that Milham or other epidemiologists expand their study to
include the other occupations I have suggested above. I further propose
that age-adjusted mortality rates be calculated for the existing data to
determine whether length of exposure or date of exposure is significant and
whether chemical exposure of these hams might be significant. I am certain
that electromagnetic radiation has effects on the human body, but I do
believe that electromagnetic radiation is the major cause of the increase
in cancer deaths as stated by Dr. Milham.
For those persons interested in further study on the effects of
electromagnetic radiation, I would suggest the American National Standards
Institute document ANSI C95.1-1982, Safety Levels with Respect to Human
Exposure to Radio Frequency Electromagnetic Fields, 300 kHz to 100 GHz.
This standard contains an appendix listing numerous references on the
biological effects of radio-frequency electromagnetic fields. A number of
other standards exist for radio-frequency and microwave exposure; many of
these are listed in the Microwave Engineer's Handbook, Vol. 2.
If anyone has read Dr. Milham's original article, I would appreciate their
sending me the exact title and the date of publication so I might have our
library order a copy. I would also appreciate the comments of other
amateurs as well as physicians on this subject. Please email responses
directly to me and I will summarize or cross-post your replies to both
rec.ham-radio and sci.med (many hams on ARPA receive their postings via an
automatic mailing list rather than a newsgroup).
Thanks and 73 [ham radio jargon for best regards].
Barry L. Ornitz WA4VZQ
-----------------
| ___ ________ |
| | / / | | Barry L. Ornitz UUCP:..rutgers!rochester!kodak!ornitz
| | / / | | Eastman Kodak Company
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| | \ \ | | P. O. Box 1972
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-----------------gwyn@brl-smoke.ARPA (Doug Gwyn ) (01/06/88)
In article <1077@kodak.UUCP> ornitz@kodak.UUCP (barry ornitz) writes: > Cause Expected Actual > Leukemia 29 36 > Lymphatic etc. Cancers 72 89 > Prostate Cancer 67.6 (!) 78 >I am not sure about the statistical differences between these numbers, That's not too hard. In lieu of further information, note that these are "rare event counts". Generally you can assume Poisson statistics in such cases. This means the probable error of the estimate is the square root of the estimated count, or approximately 6, 9, and 8 respectively. Roughly 2/3 of the time, the Actual should fall within this range of the Expected, if there is no significant correclation. Although the observed deviations are somewhat larger than expected, no one measurement has statistically significant deviation from chance at the 95% probability level. The composite probability for the set of three measurements may be such that it can be taken as an indication of a correlation (I don't want to bother with the arithmetic), but I can tell by inspection that it won't be a really strong indication. >"amateur radio operator licensees in Washington >state and California have significant excess mortality due to acute myloid >leukemia, multiple myeloma and perhaps certain types of malignant >lymphoma." This is simply a misleading statement. Each is significant only at probability levels well below general statistical practice (90%, 95%, or 99%). >I believe that other causality should be investigated by the medical >profession before Dr. Milham's conclusions are accepted. Quite right. Even a statistically significant correlation does not necessarily imply a direct causal relationship. Conclusions such as "amateur radio radiation causes cancer" cannot be reliably drawn from this evidence. I don't know whether it does or not, frankly, and the evidence is inconclusive. At best, it may guide further research (has anyone tried subjecting lab mice in large numbers to higher dosages?).
wtm@neoucom.UUCP (Bill Mayhew) (01/07/88)
Sicne it is a medical school I work in, the recent spate of reports on the purported carcinogenic effects of electromagnetic fields has been a strong topic of converstion. I'm not convinced that the methodolgy of the study has been carfully controlled enough to rule out effects other than electromagnetic exposure. For instance, the authors make a statement to the effect: "The lukemia rate was found to be higher near the origin of power lines where the current being carried higher..." Of course people that live near the origins of power lines also typically live closer to industrial regions too, but this was not discussed. Another interesteing thought is that the earth's steady state magnetic field is hundreds of times larger than the fields imparted by exposure to the power grid. I'm not really qualified to argue steady-sate vs. 60 Hz effects- I'd be interested in hearing from somebody who is. 60 Hz is a very long wavelength, so it would seem that it could be considered virtually steady sate -- maybe not. At least, I'm glad that the topic is being studied. I just hope that the researchers conduct themselves in a responsible manner. --Bill
keithl@vice.TEK.COM (Keith Lofstrom) (01/08/88)
There may or may not be something here, but it can't be found simply by counting death certificates. For example: what if, for some reason, hams have a lower heart disease rate than the general population, and live longer? Cancer primarily strikes in old age. A cure for heart disease would show up in non-age-specific statistics as a powerful carcinogen. How old were those hams when they died? -- Keith Lofstrom ...!tektronix!vice!keithl keithl@vice.TEK.COM MS 59-316, Tektronix, PO 500, Beaverton OR 97077 (503)-627-4052
caf@omen.UUCP (Chuck Forsberg WA7KGX) (01/08/88)
: Expected Actual
: Cause Deaths Deaths
:--------------------------------------------------------------------------
: Leukemia 29 36
: Lymphatic & Blood Forming
: Organ Cancers 72 89
: Prostate Cancer 67.6 (!) 78
With such weak evidence as this, I'm surprised the author came to any
conclusions at all! (The other figures are undoubtedly less convincing,
otherwise they would have been published.)
While Ham Radio fans come from all walks of life, I'd be positively
amazed if they represent a precise cross section of the general
population. More likely, the ham radio population is significantly
skewed in favor of technicians, tinkerers and craftsmen, and these
are not 50th per centile of anything, in most ways one might care to
measure. There are probabaly more "nerds" than football fullbacks
in ham radio, and their medical profiles may differ as well.
In the meantime, I nominate Milham honary editor of the Journal of
Irreproducible Results.
Chuck Forsberg WA7KGX Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ
...!tektronix!reed!omen!caf Omen Technology Inc "The High Reliability Software"
17505-V Northwest Sauvie Island Road Portland OR 97231 VOICE:503-621-3406:VOICE
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omen!/usr/spool/uucppublic/FILES lists all uucp-able files, updated hourlygreg@mind.UUCP (Greg Nowak) (01/08/88)
In article <2174@vice.TEK.COM> keithl@vice.TEK.COM (Keith Lofstrom) writes: >There may or may not be something here, but it can't be found simply by >counting death certificates. For example: what if, for some reason, >hams have a lower heart disease rate than the general population, and >live longer? Cancer primarily strikes in old age. A cure for heart >disease would show up in non-age-specific statistics as a powerful carcinogen. >How old were those hams when they died? Let's not forget that hams are also not a random sampling. For starters, they probably have much higher disposable income than average... which would affect a number of other things, such as diet, travel, and so on. Given these factors, I don't find the slightly-higher-than-expected numbers that surprising. -- greg
robert@uop.edu (Robert McCaul -- The Equalizer) (01/10/88)
In article <1562@mind.UUCP>, greg@mind.UUCP (Greg Nowak) writes: > In article <2174@vice.TEK.COM> keithl@vice.TEK.COM (Keith Lofstrom) writes: > Let's not forget that hams are also not a random sampling. For > starters, they probably have much higher disposable income than > average... which would affect a number of other things, such as diet, > travel, and so on. Given these factors, I don't find the also many hams i know are vets, that is to say, they were exposed to situations and environs that most of us were not.. my room-mate dan, his dad was with the 101st ABN in WW-II. he was later used in nuke tests, he and his group were in trenches 10 miles from a test, all the guys at the 8 mile trench are dead or on the way with cancer and other auto immune troubles.. not to say this is true for everyone, but many hams i know have been in military or other technical service, and exposed to more than their share of many things..