emf issues and epidemiology - the source s/eei... · 7/8/2010 · emf issues and epidemiology...
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EMF Issues and Epidemiology
Gabor Mezei, MD, Ph.D.Environment
Edison Electric InstituteOccupational Safety and Health Committee ConferenceOctober 7, 2008
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Electric Power Research Institute
EnvironmentAir Quality
Global Climate Change
Electric and Magnetic Fields (EMF)Occupational
Health & SafetyLand & GroundwaterWater & Ecosystems
Power Delivery & Markets
TransmissionSubstations
Grid ReliabilityPower Markets
Distribution Power Quality
Energy Utilization
Nuclear PowerComponent
Reliability & SafetyNuclear Operations & Asset Management
Nondestructive Evaluation
Plant Technology
GenerationEnvironmental Control Fossil Steam Plants
Combustion Turbines Market Analysis
Renewables Hydroelectric
Distributed Resources
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USA Today Nov 10, 2006
Why be concerned with EMF?
Possible Human Carcinogen (Group 2B)
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Topics
Health Risk Assessments and Reviews• IARC Monograph• WHO Environmental Health Criteria• California Dept of Health Services• BioInititativeMain Research Areas• Childhood Leukemia• Miscarriage• Occupational Exposure
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Scientific Consensus
IARC 2002
“Extremely low-frequency magnetic fields are possibly carcinogenic to humans (Group 2B).”
– “…limited evidence in humans… in relation to childhood leukemia.”
– “…inadequate evidence in experimental animals for … carcinogenecity…”
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Scientific Consensus
WHO EHC 2007
• Accepts IARC Group 2B based on childhood leukemia epidemiology
– Epidemiology evidence is inadequate for other cancers and other diseases
– Evidence does not support an association for breast cancer and cardiovascular disease
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“California” View
California Dept of Health Services 2002
• “…inclined to believe that EMFs can cause … childhood leukemia, adult brain cancer, Lou Gehrig’s Disease, and miscarriage.”
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BioInitiative Working Group
BioInitiative Report 2007• “…existing public safety standards… look to
be thousands of times too lenient.”–“…a reasonable approach would be 1 mG
(0.1 µT) …to all new or upgraded power lines …”
• “… little doubt that … ELF causes childhood leukemia.”
• “strong evidence” for other diseases (e.g., breast cancer and Alzheimer’s)
• Essentially no discrimination between ELF and RF (cell phone and brain cancer)
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EMF Childhood Leukemia Pooled Analyses
Ahlbom et al., British J. Cancer 2000
• 9 studies• 3,247 cases; 10,400 controls• Geometric mean
Greenland et al., Epidemiology 2000
• 12 studies• 2,656 cases; 7,084 controls• Time-weighted average
0.5
1.0
1.5
2.0
2.5
3.0
3.5
<1 1-2 2-4 >4Magnetic Field (mG)
Odd
s R
atio
(±95
% C
I)
0.5
1.0
1.5
2.0
2.5
3.0
<1 >1 - 2 >2 - 3 >3Magnetic Field (mG)
Odd
s R
atio
(±95
% C
I)
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Why The Association?
• Control Selection Bias
• Some Other Exposure?
IContact
RS
RP
V2
V1
SPContact
RRVVI
+−
=21
IContact
RS
RP
V2
V1
SPContact
RRVVI
+−
=21
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TransExpo
International Study of Childhood Leukemia and Residences above Transformer Rooms
• No subject participation required to assess exposure
– Limit/exclude selection bias
• Focus on highly exposed population
• Funded by EPRI
Great Potential Scientific Impact!
15
NetherlandsPortugalChinaBulgariaIsraelBelgiumSpainKoreaItalyHungaryBrazilPolandFranceSwitzerlandFinland
ArmeniaNorwaySwedenCroatiaRomaniaCanada
Too SmallNo Responseyet
Pilot Under Consideration
TurkeyJapan UKUSDenmark AustriaMexico
AustraliaUkraineGermanyRussia
Not FeasibleTo be Explored
ContactedInterested/Being
Explored
Pilot Ongoing
TransExpoStatus of Participation by Country
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The Northern California Childhood Leukemia Study (NCCLS)
• NIH-funded large case-control study of childhood leukemia– Environmental and genetic risk factors
Cases0-14 years oldIncident leukemiaNo previous cancerResident of 35-county study area English or Spanish-speaking
Controls randomly selected from CA birth registry, matched to cases on child’s age, sex, Hispanic status, and maternal race
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NCCLS – EPRI Component
• Investigate link between risk of childhood leukemia and – Residential contact voltage– Residential magnetic fields– Wire configuration codes
ContactVoltage Magnetic
FieldW-L Wire
Code
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UK Study (Draper et al, 2005):
• Is childhood cancer associatedwith distance from transmission lines?
• Result
– Leukemia risk versus distance from lines
• At <200 m, a 69% increase
• At 200-600 m, a 23% increase
• However, negligible magnetic field beyond ~150m
• EPRI conducting replication in California
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Replication of Draper Study in California
Record Linkage• California Cancer Registry• California Birth Registry• GIS information of California
utilities and addresses of cases and controls
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Childhood Leukemia Survival Study
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Foliart et al. 2006 – Overall Survival
0.1
1
10
<1 1 - <2 2 - <3 >=3 Magnetic Field (mG)
Rel
ativ
e R
isk
(w/9
5% C
I)
16/235
7%
7/87
8% 1/19
5%
4/18
22%
13.8
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German Childhood Leukemia Survival Study
Results Conclusions• “…broadly consistent…”• “…poorer survival…”• “…small numbers…”• “…biological
mechanism… is not known.”
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Childhood Leukemia Survival Pooled Analysis
571875223529GRAND TOTAL381293352548TOTAL33421Sweden
02792Norway
12225Finland
222598Denmark
03872New Zealand
123888239Canada
31347906UK
1766177595US Case-control
1958187981TOTAL71852595Germany
1240135386US Survival study
>0.4 µT>0.2 µT>0.1 µTN ALL
Next Step
• Follow up of cases from previous studies
• Combined analysis
• EPRI funding
• Project to start in 2008
Estimated number of cases
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Miscarriage
Pre-2002• Inadequate evidence to link EMF to pregnancy outcomes
(NIEHS 1998)
Li et al. 2002; Lee et al. 2002• Consistently increased risk of miscarriage with peak
exposure > 16 mG– Higher risk among “susceptible”
• No association with mean MF
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Miscarriage
Savitz 2002• Mobility hypothesis
Mezei et al. 2005Savitz et al. 2006• Evidence for an association between mobility and peak
MF
Kaiser replication• In progress• Funded by NIH
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Miscarriage
Main Issues• Most miscarriages occur in early pregnancies
– Some undetected• Information on mobility and miscarriage• If effect is real then great public health impact
Study of Women with Assisted Reproductive Technologies (ART)
• Intrauterine insemination (IUI)• In vitro fertilization (IVF)• Intracytoplasmic sperm injection (ICSI)
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Miscarriage
EPRI to Join Ongoing Study• EPRI to add simultaneous measurements
– MF exposure (EMDEX)– Activity monitor (e.g., accelerometer)
Main Advantages• Known date of conception• Highly motivated women• “Susceptible” population• Involvement of couples
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Occupational EMF and Leukemia and Brain Cancer: An Update to Two Meta-Analyses
Background• Two meta-analyses in 1995 and 1997 showed a small
increase in risk of adult leukemia and brain cancer with occupational EMF exposure
• Number of new studies have since been published• WHO evaluation of ELF-EMF recommended update• Systematic literature search identified 20 new publication
on brain cancer and 21 on leukemia
• Kheifets et al. JOEM 2008
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Results
Past and New Studies Cumulative Plot
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Results
Past and New Studies Cumulative Plot
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Results
Past and New Studies Meta-Analysis
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Conclusions
• No clear exposure pattern• Results do not depend on methods or individual studies• Pooled risk estimates were lower than in past meta-
analyses– Leukemia subtypes showed no consistent pattern
when past and present meta-analyses were compared.
• The lack of a clear pattern of EMF exposure and outcome risk does not support a hypothesis that these exposures are responsible for the observed excess risk
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Implanted Medical Devices
• Fast advancing technology– Standards and testing bodies cannot cope
• Types of failures are not readily anticipated• Aging workforce requiring such devices• Clinical/Regulatory/Compliance testing is costly, time
consuming– Not necessarily protect against litigation
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Implanted Medical Devices
• Potential interference from occupational 60 Hz or RF sources• Practical research to characterize exposure and improve
safety– Evaluate interference potential: signal confounding,
device damage, undesired or lethal operations, inhibition• May develop small 60 Hz personal monitor to alarm at preset
threshold– Facilitate work by users; avoid complex measurements
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Radio-Frequency (RF) Safety
New Issue for Electric Utilities• Wireless Antennas
– Leased space on T&D structures– New exposure for workers (RF)
• FCC RF exposure limitsEPRI RF Work• Characterize RF Exposures• Provide Information, Education,
Training• Demonstration of Compliance with
Government Regulations
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EMF Success Story
Researchand
Communication
Filter
ChildhoodLeukemia(miscarriage)
(ALS)
NowThen (~1988-93)Birth Defects
MiscarriageChildhood Cancer
Adult CancerALS
Alzheimer’s DiseaseDepression
Others
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Thank You!
Contact Information
Gabor Mezei, MD, Ph.D.EPRI Environment3420 Hillview AvenuePalo Alto, CA 94304www.epri.com
Phone: (650) [email protected]