EMF Issues and Epidemiology

Gabor Mezei, MD, Ph.D.Environment

Edison Electric InstituteOccupational Safety and Health Committee ConferenceOctober 7, 2008

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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) 855-8908gmezei@epri.com