European Foundation of Oncology and Environmental Sciences “B. Ramazzini”

Cesare Maltoni Cancer Research Center

June 28 2007

The potential carcinogenic risks of

electromagnetic fields: what we know and what

we still must learn

Bologna Summer Event

2

Power frequency EMF:

what we know

3

Power frequency EMF: epidemiological evidence

The first epidemiological study of childhood cancer and EMF was published in 1979.

Since then more than 20 studies have been conducted

The present position on EMF and the epidemiology of childhood leukemia is summarized in a pooled analysis of measurement and calculated field studies published by Ahlbom et al (3247 cases in total).

4

Pooled results from Ahlbom et al

20.14.4

24.2

368

44

1.87 (1.1-3.2)2.13 (0.9-4.9)

2.00 (1.3-3.1)

1.15 (0.9-1.5)0.79 (0.3-2.3)

1.11 (0.8-1.5)

1.05 (0.9-1.3)1.58 (0.8-3.3)

1.08 (0.9-1.3)

Measurements studiesCalculated field studies

All studies

Summary

00.22.71.5

2105

2 cs/0 ct6.21

0 cs/10 ct3.74

0 cs/8 ct4.111.060.57

2.680 cs/19 ct

1.751.75

DenmarkFinlandNorwaySweden

Calculated field studies

10.30.90

4.44.7

13204

17

1.552.00

0 cs/0 ct1.003.44

1.391.67

4 cs/0 ct0.981.01

1.291.240.670.841.11

CanadaGermanyNew ZealandUKUSA

Measurement studies

ExpectedObserved

≥ 0.4 µT≥ 0.4 µT0.2-<0.4 µT0.1-<0.2 µTStudy

Numbers of subjectsRelative risks (and 95% confidence intervals)

5

Animals Treatment Result Comments Authors

Species/strain No. Exposure Duration

Margonato et al.,

1995

Rats

S.D.

256 males

per group

0; 5 µT

(50 Hz)

32 weeks

(22 h/day)

No evidence of

carcinogenic effect

Yasui et al.,

1997

Rats F344

48 females

per group

0;0,5; 5 mT

(50 Hz)

2 years

(22 h/day)

No evidence of

carcinogenic effect

Mandeville et al.,

1997

Rats F344 50 males and

50 females

per group

0; 2; 20; 200;

2000 µT

(60 Hz)

2 years, GLP

(20 h/day)

No evidence of

carcinogenic effect

NTP, 1998 Rats F344

Mice B6C3F1

100 males and

100 females

per species and

per group

0; 2; 200;

1000 µT

2 years, GLP

(18.5 h/day)

Equivocal evidence

of carcinogenic effect

for thyroid C cell

tumour in male

treated with 2 or

200 µT

Only 1 sex (male); short duration (32 weeks)

Few animals;short duration (104 weeks)

Only 1 sex (male); short duration (104 weeks)

Short duration (104 weeks)

Power frequency EMF: experimental evidence

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There is an association between childhood leukemias and EMF exposure in the study populations.

However, it is not yet possible to establish a cause-correlation for two reasons:

1) the absence of a plausible mechanism

2) lack of support from laboratory evidence

Present position on power frequency EMF (part I)

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These factors led IARC to classify power frequency EMF as a possible carcinogen in 2001

Were there an accepted mechanism of action or robust supporting evidence from the laboratory, it is probable that EMF would have instead been classified as an established carcinogenic agent.

Present position on power frequency EMF (part II)

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Radio frequency EMF (RFEMF):

what we know

9

1978-1995: Various epidemiological studies conducted on military personnel exposed to radar waves and on children living near radio-television aerials indicate a possible increase in limphomas/leukaemia

2001-2002: Initial epidemiological data on tumours of acustic nerves have been reassuringly negative

RFEMF: epidemiological evidence (part I)

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2004: Preliminary results of an epidemiological study condicted in Sweden report an increase in tumours of the acustic nerve in population exposed to cellular telephones (RFEMF) (Ahlbom, 2004)

2006: Pooled analysis of two case-control studies on use of cellular and cordless telephones showed an increase risk of malignant brain-tumours diagnosed in 1997-2003, highest in the group with > 10 years latency period

RFEMF: epidemiological evidence (part II)

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Animals Treatment Result Comments Authors

Species/strain No. Exposure Duration

Chou et al., 1992

Rats S.D.

100 males per group

(2,450MHz)

25 months (21.5 h/day)

Excess of primary malignant tumors

Repacholi et al.,

1997

MiceEm-Pim1

100 females per group

(900 MHz)

18 months (1h/day)

No evidence of carcinogenic effect

Utteridge et al., 2002

120 females per group

(900 MHz)

2 years (1h/day)

No evidence of carcinogenic effect for mammary tumors

Bartsch et al.,

60 females

(23 h/day)

Only 1 sex (male); short duration (110 weeks)

Only 1 sex (female); short duration (78 weeks)

Few animalsshort duration (sacrificed within 1 year)

2002

MiceEm-Pim1; w.t.

Rats S.D. per group

(900 MHzand DMBA)

Increase risk of lymphomas

Only 1 sex (male); short duration (104 weeks)

RFEMF: experimental evidence

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Present position on RFEMF

Use of cell phones for < 10 years have not demonstrated an increase in cancer

There is however some evidence regarding long-term use and lengthy latency period

absence of evidence ≠ absence of risk

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EMF and RFEMF:

what we still must learn

14

EMF and RFEMF represent what are known as diffused carcinogenic risks.

We use this term to describe carcinogenic risks of low potency, but to which almost the entire population of the planet may be exposed.

Diffused carcinogenic risks

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1) agents which are slightly carcinogenic at any dose;

2) low or extremely low doses of strong carcinogenic agents;

3) mixtures of small doses of any carcinogenic agents.

Examples of diffused carcinogenic risks

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In the case of diffused carcinogenic risks, it is not sufficient to follow the standard protocol used in ordinary experiments,

but rather it is necessary to conduct what we define as mega-experiments.

Tools for identifying diffused carcinogenic risks

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Characteristics of mega-experiments

reproduce the various conditions of human exposure

use vast numbers of animals per group, in order to express variations in the effects more sharply

are conducted until the natural death of the rodents, to allow an agent to express its full carcinogenic potential

evaluate all neoplastic and non-neoplastic pathologies

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35 years of mega-experiments at the ERF

agent # rodents

vinyl chloride > 7,000

vitamins > 8,000

coca-cola > 2,000

gamma radiation > 10,000

irradiated food > 2,000

electromagnetic fields > 9,000

extremely low frequency > 7,000

radiofrequency > 2,000

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Integrated project of the European Ramazzini

Foundation (ERF)

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ERF mega-experiments to evaluate EMF (50Hz)

7,133 TOTAL

50Hz-magnetic field and aflatoxin B1

642BT 4 CEM

50Hz-magnetic field and 10 gamma rads

657BT 3 CEM

50Hz-magnetic field and formaldehyde

805BT 2 CEM

50Hz-magnetic field5,029BT 1 CEM

TreatmentNumber of animals (M+F)

Experiment Duration

Lifespan

Lifespan

Lifespan

Lifespan

Age at start

embryo

embryo

embryo

embryo

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ERF mega-experiment on EMF (50Hz)

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ERF mega-experiment to evaluate RFERF (1.8 GHz)

2,448TOTAL

0 Volt/meter (control) 817IV

5 Volt/meter 811III

25 Volt/meter 411II

50 Volt/meter409I

Treatment (Volt/meter)Number of animals (M+F)

Group number

Experiment BT 1 CEMRF

Duration

Lifespan

Lifespan

Lifespan

Lifespan

Age at start

embryo

embryo

embryo

embryo

23

ERF mega-experiment on RFEMF (1.8 GHz)

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The epidemiological evidence concerning EMF and long-term exposure to RFEMF show there are reasonable grounds for concern for the possibility of adverse effects

The absence of epidemiological evidence concerning short-term exposure RFEMF ≠ the absence of risk

While we await the results of the experiments currently underway (2009-2011), the precautionary principle guides us to “undertake provisional risk management measures…without having to wait until the reality and seriousness of those adverse effects become fully apparent”

Conclusions