International Radiation Protection Association 11 th International Congress Madrid, Spain - May 23-28, 2004 Keynote Lecture 8a Mobile Telephony: Evidence of Harm? Bernard Veyret (F)
Outline 1. Mobile telephony 2. Interaction 3. Research 1. Exposure systems 2. Mechanisms 3. Laboratory studies 4. Epidemiology 4. Health risk assessment 5. Conclusion IRPA 11 Keynote Lecture 8a 2
Mobile Telephony: context Rapid development over the past 10 years More than 1.3 G phones in use in the world Several protocols (TDMA, CDMA) and generations (2G, 3G, ) Health concerns mainly about base stations IRPA 11 Keynote Lecture 8a 3
Mobile Telephony: how it works QuickTime et un décompresseur TIFF (LZW) sont requis pour visionner cette image. IRPA 11 Keynote Lecture 8a 4
Interaction with tissues First time a microwave source is placed against the head Half of the emitted energy absorbed in the head (half of it in the skin) Frequency range: 400 to 2.1 GHz (GSM: 0.9 and 1.8 GHz) IRPA 11 Keynote Lecture 8a 5
Specific aborption rate (SAR) SAR is the metric for local or whole-body deposition of microwave power SAR in W kg 1 SAR = c DT / Dt ICNIRP s exposure guidelines: basic restriction local exposure: 2 W kg 1 averaged over 10 g whole-body exposure: 0.08 W kg 1 IRPA 11 Keynote Lecture 8a 6
Thermal vs. Non-thermal effects A thermal effect is due to D T (or triggering of thermoregulation) Exposure to base stations is negligible (ca. 1/10000 of the limit) Exposure to mobile telephones is close to the limit (ca. 1/10 of the limit) Temperature elevation in the skin is minimal and < 0.1 C at the periphery of the brain IRPA 11 Keynote Lecture 8a 7
SAR? SAM QuickTime et un décompresseur TIFF (LZW) sont requis pour visionner cette image. IRPA 11 Keynote Lecture 8a 8
Phantoms IRPA 11 Keynote Lecture 8a 9
T = f(sar) SAR Temperature IRPA 11 Keynote Lecture 8a 10 Hirata et al., IEEE Trans EMC 2003
Research activity 15 M / year worldwide International programmes EU (Interphone, Perform A&B, Reflex, Cemfec, Ramp, Guard, EMF-NET) Other multicenter programmes National programmes Italy, UK, Finland, France, etc. Japan Australia Industry ARIB, MMF, GSMA IRPA 11 Keynote Lecture 8a 11
WHO database Cancer relevant or related Type of study Completed Ongoing Total Epidemiological studies 12 24 36 Standard bioassays 8 7 15 Sensitized in vivo studies 13 7 20 Acute in vivo studies 23 8 31 In vitro studies 57 25 82 Total cancer studies 113 71 184 IRPA 11 Keynote Lecture 8a 12
WHO database Non-cancer studies Type of study Completed Ongoing Total Epidemiological studies 10 1 11 Human studies 50 21 71 Acute in vivo studies 37 10 47 In vitro studies 15 7 22 Total non-cancer studies 112 39 151 IRPA 11 Keynote Lecture 8a 13
Mechanisms Threshold mechanism is assumed: thermal effects are well established Heating is the only mechanism accepted so far but others are being investigated IRPA 11 Keynote Lecture 8a 14
Exposure systems: in vitro QuickTime et un décompresseur TIFF (LZW) sont requis pour visionner cette image. Coplanar Waveguide system Shorted waveguide IRPA 11 Keynote Lecture 8a 15 Wire patch antenna
Exposure systems: in vivo Loop antenna carousel IRPA 11 Keynote Lecture 8a 16 Ferris wheel
Cellular studies Genotoxicity (DNA damage, SCE, MN, etc.) Apoptosis Proliferation Transformation Gene expression Enzyme activity (ODC, NOS2, etc.) Gap junctions Heat shock proteins (HSP) No evidence of genotoxicity; open questions on HSPs; genomics proteomics? IRPA 11 Keynote Lecture 8a 17
Animal studies: cancer Long-term bioassays 8 published studies : negative 2 ongoing studies 1 planned study Promotion studies 10 published studies All negative but that of Repacholi et al. 97 8 studies ongoing (incl. replications) Generally no effects observed IRPA 11 Keynote Lecture 8a 18
Animal studies: non-cancer Behaviour perception, work stoppage, endurance, activity, learning and memory, performance Evidence of effects at SAR above 4 W kg 1 (whole-body) Reproduction and development very few studies related to mobile telephony Blood-brain-barrier (BBB), hearing, skin All effects seem to be related to temperature increase IRPA 11 Keynote Lecture 8a 19
Human studies CNS Sleep/EEG Cognitive and behavioural functions (memory, task performance, reaction times, etc.) Cardiovascular system heart rate, arterial pressure,etc. Hearing Hypersensitivity Inconsistent data. No conclusive evidence of effects IRPA 11 Keynote Lecture 8a 20
Epidemiological studies Mainly on cancer Mainly on mobile telephones 8 published studies: negative but not informative (exposure assessment, statistical power,etc.) Interphone (13 countries), coordinated by IARC: tumours of head and neck one paper already published, more to come conclusion by the end of 2005? IRPA 11 Keynote Lecture 8a 21
Health risk assessment ICNIRP had a statement on mobile telephony in 1996 WHO has reviewed the science on RF and health and issued research recommendations in June 2003 The main conclusion from these reviews and others is that EMF exposures below the limits recommended by ICNIRP guidelines do not appear to have any known impact on health IRPA 11 Keynote Lecture 8a 22
Health risk assessment (cont.) However, there are still some key gaps in knowledge requiring further research to provide definitive health risk assessments IARC will issue a cancer classification of RFR in 2005 and WHO and ICNIRP s evaluations on RFR and health are due in 2006. IRPA 11 Keynote Lecture 8a 23
Conclusion Major research activity Many national and international expert-group reports published: Weight of scientific evidence today does not support health concerns or indicate any health risks from mobile phones in normal use Usage will change and exposure of the head will tend to decrease Open questions include a potential greater sensitivity of children IRPA 11 Keynote Lecture 8a 24
QuickTime et un décompresseur TIFF (LZW) sont requis pour visionner cette image. IRPA 11 Keynote Lecture 8a 25