Transcript Cell Phones and Human Health: An Update on Research and

Cell Phones and Human Health:
An Update on Research and
Regulations
Presented at AIHCE
June 6, 2001
Marty Eroh, CIH
Pinnacle West Corporation
[email protected]
Cell Phone - Background
 Use of cell phones has grown dramatically over
the last fifteen years.
 Operate at frequencies slightly higher than TV and
FM Radio signals (Nonionizing).
 Analog and digital phones operate in the
frequency range of 900 - 1800 MHz.
 The maximum powers of these phones are 2W and
1W (900 and 1800 MHz respectively). Average
power are 1/8 of maximum.
EM Spectrum
Basic Operation
 Mobile phones communicate with base
stations (fixed installations).
 Base stations have limited range, therefore
requires a nationwide network.
– Macrocells - up to about 22 miles, power output
in tens of watts.
– Microcells - infill, airports, railway stations.
Range of few hundred yards.
– Picocells - Sited inside buildings. Low power.
Sources of Exposure
 Mobile phones and base stations -
exposures reduce with distance from the
source.
 Mobile phones - principal exposure is to the
side of the head for hand held, or to other
body parts during hands free use.
 Base station exposure is whole body, but
much lower intensity than from handsets.
Typical and Atypical Base
Stations
Typical and Atypical Base
Stations
Typical and Atypical Base
Stations
Typical and Atypical Base
Stations
Typical and Atypical Base
Stations
Typical and Atypical Base
Stations
Current Basis of Exposure
Guidelines
 Primary sources of exposure guidelines,
including IEEE, ICNIRP, NRPB are all
based on avoiding thermal effects.
 Some variation in the limits, e.g. some
limits build in a safety factor for the general
public vs workers.
Exposure Limits (cont.)
 Most exposure limits are now provided in
two forms:
– Basic Restrictions - based on SAR - difficult to
measure.
– Reference or Investigation Levels - based on
field strengths (v/m, A/m, or W/m2), more
easily measured.
 Can exceed the reference levels as long as
the basic restrictions are not exceeded.
Example of ICNIRP Guidelines
 Basic restrictions
 Reference level for
 Whole Body SAR =
general public at cell
phone frequency
 1800 - 1900 MHz = 9
- 9.5 W/m2 (based on
f in MHz/200)
0.4 (0.08) W/kg
averaged over 6
minutes.
 Head / trunk SAR =
10 (2) W/kg based on
10 grams of mass and
6 minute average.
 ( ) denotes public.
Are there Non-thermal Effects?
 Is there justification for standards below
thermal limits?
 Do biological effects = adverse health
effects?
 What areas of research deserve attention?
 What approach should be taken while
research is being completed?
IEGMP
 Independent Expert Group on Mobile
Phones report from Great Britain, April
2000.
 Good overall summary of the science to
date.
 Review this report and a few more recent
publications.
IEGMP Overall Conclusions
 Despite widespread use, there is little
research specifically relevant to cell phones.
 The balance of evidence to date suggests
that there are no adverse health effects
below current ICNIRP guidelines (only
thermal effects).
 Some evidence for biological activity below
the guidelines, but not clear that they lead to
disease.
IEGMP Overall Conclusions
(Cont.)
 Not possible to say that exposures below
guidelines are totally without potential
adverse health effects; knowledge gaps
justify precautionary approach.
 Due to well-documented detrimental effects
drivers should be dissuaded from using
either hand-held or hands-free phones while
on the move.
Biological Interaction
 Force produced by an electric field on
charged objects (ions in the body) causes
them to move, results in electric currents.
Currents flowing through resistance of the
material results in heating. Heat input
causes increased blood flow for heat
dissipation (equilibrium).
 Increase in brain temp by cell phones is
estimated to be 0.1 C (to equilibrium).
Biological Interaction
 The energy quanta at cell phone frequencies
is 4 - 7 micro eV (millionth of eV). Energy
needed to break chemical bonds in DNA is
1 eV. Insufficient power to break bonds.
 Electric field created in biological tissue.
But to produce detectable changes, these
fields would need to be greater than thermal
or random noise.
Potential Biological Interaction
 Could fields induce cell polarization?
 Could fields affect movement of ions
through cell membrane channels?
 Does it increase ODC Activity?
 Do fields effect gene expression?
 Others?
 If any of these effects are real, do they result
in an adverse health outcome?
Epidemiologic Evidence
 Few studies directly examining cell phones
and health effects.
 Latency of certain diseases, changes in
technology, and changes in usage patterns,
is an overall weakness in cell phone
epidemiology.
Two Recent Hospital Based
Case-Control Studies
 Muscat et al., JAMA 2000; 284:3001-7
 Inskip et al., NEJM, 2001;344: 79-86
 469 and 782 cases of brain CA respectively.
 Controls were either benign disorders or
cancers other than lymphoma and leukemia.
 Exposure assessment through questionnaire.
– Duration and frequency of use.
– Type of phone, handedness
Results of Muscat and Inskip
 No association between measures of cell
phone use and risk of brain cancer (total,
site specific, or by histological type).
 Limitations
–
–
–
–
Exposure assessment (questionnaire)
No measurements
Low usage / short latency
Hospital controls
Cohort Study in Denmark
 Johansen et al., Journal of the NCI, 2001
 Nationwide cohort study of cell phone
users.
 Linked to Danish cancer registry.
 Standardized Incidence Ratios (SIR) observed to expected.
Denmark Study - Results
 No excess risk of any cancers. Example
SIRs.
 All cancers: 0.86 (men), 1.03 (women)
 Brain / nervous system: 0.95 (m), 1.03 (w)
 Salivary gland: 0.78 (m), 0 cases in women
 Leukemia: 0.97 (m), 1.07 (w)
Recommended Research
(IEGMP)
 Epidemiologic studies. Case control and
cohort. Particularly due to latency and
changes in technology.
 Studies of brain function.
 Consequences of exposures to pulsed fields.
 Subcellular and cellular research.
 Improved exposure assessment
 50:50 funding, independent panel
IEGMP Precautionary Approach
 Prefer the two-tiered approach to exposure
limits - general public versus workers, or
controlled versus uncontrolled
environments.
 Establishment of exclusion zones around
base stations where exposure guidelines
may be exceeded.
 Signs on micro and picocell transmitters
stating do not open when in use.
IEGMP Precautionary (cont.)
 More open process in the siting of base
stations.
 Pursue a policy of mast sharing and
roaming where practical to minimize base
stations.
 Provide information on SAR to mobile
phone consumers.
IEGMP Precautionary (cont.)
 Non-essential use of cell phones by children
should be discouraged.
 Drivers should be dissuaded from using any
type of cell phone while moving.
Cautious Inaction
 Trichopoulos from Harvard and Adami from
Karolinska Institute, Editorial in NEJM:
Discussing radio-frequency energy stated:
– ‘…the lack of a theoretical foundation and the
absence of empirical evidence of a substantial
increase in risk legitimize cautious inaction,
unless and until a small excess risk is firmly
documented.’
SUMMARY:
 Known Risks:
– Heating - existing standards are protective.
– Use of cell phone while driving.
 Need For Further Research - Potential non-
thermal effects and long term epidemiology.
 In the interim: Precautionary Approach or
Cautious Inaction.
Regulatory / Exposure Guidance
 FCC
– 47 C.F.R., Part 1 Subpart I (1.1301 - 1.1319)
NEPA
– 47 C.F.R.,Part2 Subpart J (2-1091 - 2-1093) RF
Exposure, Mobile and Portable Devices
– OET Bulletin 65, “Evaluating Compliance with
FCC Guidelines for Human Exposure to RF
EMF,” 8/97 (http://www.fcc.gov/oet/rfsafety)
– OET Bulletin 56, Q&A About the Biological
Effects & Potential Hazards of RF EMF.
Regulatory / Exposure Guidance
(cont.)
 IEEE C95.1-1991 (1999 Edition), IEEE Standard
for Safety Levels with Respect to Human
Exposure to Radio Frequency Electromagnetic
Fields, 3 kHz to 300 GHz
 IEEE C95.2-1999, IEEE Standard for
Radiofrequency Energy and Current Flow
Symbols
 IEEE C95.3-1991, IEEE Recommended Practice
for the Measurement of Potentially Hazardous
Electromagnetic Fields - RF and Microwave
Selected Bibliography
 Adey, WR et al. Spontaneous and nitrosoursea-
induced primary tumors of the central nervous
system in Fischer 344 Rats exposed to frequency
modulated microwave fields. Cancer Research,
60: 1857-1863, 2000.
 Elwood JM. A Critical Review of Epidemiologic
Studies of Radiofrequency Exposure and Human
Cancers. Environ Health Perspectives, 1999:107
(suppl 1): 155-168
Selected Bibliography (Cont.)
 Inskip, PD et al. Cellular telephone use and brain
tumors. New England Journal of Medicine,
January 11, 2001.
 Inskip, PD. Frequent radiation exposures and
frequency-dependent effects: the eyes have it.”
Epidemiology, 12(1):1-4, 2001.
 Johansen, C et al. Cellular telephones and cancer –
a nationwide study in Denmark. Journal of the
National Cancer Institute, 93(3): 203-07, 2001.
Selected Bibliography (Cont.)
 Lai, H; Singh, NP. Acute low-intensity microwave
exposure increases DNA single-stranded breaks in
rat brain cells. Bioelectromagnetics 16(3):207210, 1995.
 Lai, H; Singh, NP. DNA single- and double-strand
DNA breaks in rat brain cells after acute exposure
to low-level radiofrequency electromagnetic
radiation. International Journal of Radiation
Biology, 69:513-521, 1996.
Selected Bibliography (Cont.)
 Krewski, D et al. Potential health risks of
radiofrequency fields from wireless
telecommunications. Journal of Toxicology &
Enviornmental Health Part B: Critical reviews,
4(1): 1-143, 2001.
 Krewski, D et al. Recent advances in research on
radiofrequency fields and health. Journal of
Toxicology & Enviornmental Health Part B:
Critical reviews, 4(1): 145-159, 2001.
Selected Bibliography (Cont.)
 Morgan, RW et al. Radiofrequency exposure and
mortality from cancer of the brain and
lymphatic/hematopoietic systems. Epidemiology,
vol. 11(2): 118-27, 2000.
 Moulder, JE et al. Cell phones and cancer: what is
the evidence for a connection? Radiation
Research; 151(5): 513, 1999.
 Muscat, JE et al. Handheld cellular telephone use
and risk of brain cancer. JAMA, 284(23): 3001-7,
2000.
Selected Bibliography (Cont.)
 Park, RL. Cellular telephones and cancer : how
should science respond? Journal of the National
Cancer Institute, 93(3): 166-67, 2001.
 Repacholi, M et al. Lymphoma incidence in EuPIM-1 transgenic mice exposed to 50 Hz magnetic
fields for up to 18 months: experimental
methodology and exposure system. 17th Annual
Meeting of the Bioelectromagnetics Society, June
18-22, Boston, MA, 1995.
Selected Bibliography (Cont.)
 Stang, A et al. The possible role of radiofrequency
radiation in the development of uveal melanoma.
Epidemiology, 12:7-12, 2001.
 Sienkiewicz, ZJ et al. Low level exposure to
pulsed 900 MHz microwave radiation does not
cause deficits in the performance of a spatial
learning task in mice. Bioelectromagnetics, vol.
21: 151-158, 2000.
Selected Bibliography (Cont.)
 Stewart, W. Mobile phones and health.
Independent Expert Group on Mobile Phones
(IEGMP) // Website:
http://www.iegpm.org.uk/IEGMPtxt.htm//
 Vijayalaxmi et al. Cytogenetic studies in human
blood lymphocytes exposed in vitro to
radiofrequency radiation at a cellular telephone
frequency ( 835.62 Mhz, FDMA) Radiation
research, 155: 113-121 2001
Selected Bibliography (Cont.)
 Inquiry into Electromagnetic Radiation,
Parliament of the Commonwealth of Australia,
Report of the Senate Environment,
Communications, Information Technology and the
Arts References Committee, May 2001,
http://www.aph.gov.au/senate/committee/ecita ctte/EMR/contents.htm