Epidemiological studies of RF exposures

Transcription

1 International Radiation Protection Association 11 th International Congress Madrid, Spain - May 23-28, 2004 Plenary Panel Session 3 Epidemiological studies of RF exposures Elisabeth Cardis

2 Main sources of RF exposure Occupational Military personnel Physiotherapists Sealing, bonding of materials including plastic, rubber Workers in broadcasting/communications industries Residential Amateur (ham) radios Radio/ television transmission towers Telephone base stations Mobile telephones IRPA 11 Plenary Panel Session 3 2

3 Occupational and environmental studies Epidemiological studies of occupational and environmental RF exposures: Inconsistency of results Methodological limitations Inadequate assessment of RF exposure Lack of information on potential confounders Inadequate methods (comparison groups, analyses) Not possible to evaluate existence of a cancer risk from RF IRPA 11 Plenary Panel Session 3 3

4 Brain tumours overall RR for long-term mobile phone use Reference Study period Total number of cases % users Time since start of use Long term users Number of cases RR (95% CI) Hardell, % >5 years ( ) >10 years ( ) Muscat, % >4 years ( ) Inskip, % >5 years ( ) Johansen, % >5 years ( ) Auvinen, % >2 years ( ) Hardell, ~50% >5 years 120* 1.4 ( ) >10 years 46* 1.8 ( ) IRPA 11 Plenary Panel Session 3 4 Analogue use only duration of use

5 Energy absorption is very localised and distribution depends on phone GRID X GRID X 25 mm mm mm 100 Axe tangent corps caleux 80 CACP 20 mm Axe tangent corps caleux 80 CACP Bord Ant. VCA Corps Caleux VCP GRID Z Bord Post. Corps Caleux Bord Ant. VCA Corps Caleux VCP Bord Post. Corps Caleux 25 mm Distribution of SAR in head ~29 mm From: Joe Wiart, France Telecom 29 0 Bord Ant. VCA Corps Caleux IRPA 11 Plenary Panel Session 3 VCP Bord Post. Corps Caleux 5

6 Analyses of risk by location of tumour in the brain Hardell et al, 1999, 2000 Increased risk for tumours in temporal, temporo-parietal or occipital lobes on same side as mobile phone : OR= % CI (13 tumours) Muscat et al, 2000 Overall, tumours occurred more frequently on same side of head as phone Temporal lobe (14 cases) more cases on contralateral side of head Inskip et al, 2001 No association with side of head Hardell et al, 2002, 2003 Increased risk in temporal lobe OR=2.0 95% CI Ipsilateral tumours OR=2.5 95% CI cases Contralateral tumours OR=1.5 95% CI cases should be interpreted with caution given potential for recall bias IRPA 11 Plenary Panel Session 3 6

7 Acoustic neurinoma RR for long-term phone use Reference Study period Total number of cases Time since start of use Long term users Number of cases RR (95% CI) Muscat, >3 years (n.s) Inskip, >5 years ( ) Hardell, >5 years 26* 3.7 ( ) >10 years 7* 3.5 (0.7-17) IRPA 11 Plenary Panel Session 3 7 Analogue use only duration of use

8 Conclusions Current epidemiological studies inconclusive generally negative but cannot rule out existence of a small individual risk of potential public health importance Need: Careful large studies In populations with sufficient prevalence of exposure 5-10 years ago With more detailed exposure assessment IRPA 11 Plenary Panel Session 3 8

9 The INTERPHONE Study Objectives: To assess whether RF emitted by cellular telephones are carcinogenic and To assess whether use of mobile telephones is associated with cancer risk Study Design Population based multinational collaborative case-control study Common core protocol 13 countries Focus on: glioma, meningioma, acoustic neurinoma and parotid gland tumours Much effort on exposure assessment, tumour localisation, validation of recall IRPA 11 Plenary Panel Session 3 9

10 Scope of study Participating countries Australia Italy Canada Japan Denmark New Zealand Finland Norway France Sweden Germany UK Israel IRPA 11 Plenary Panel Session 3 10

11 Scope of study Expected number of cases Brain Acoustic neurinoma Parotid gland 400 Schedule Case-ascertainment: Data collection completed First results of national studies First results of international study early 2005 IRPA 11 Plenary Panel Session 3 11

12 First INTERPHONE national results Acoustic neurinoma study (Christensen et al, 2004) 106 acoustic neurinoma cases in Denmark controls Results: No increased risk overall OR=0.9 95% CI ( ) No association with duration or amount of use Mean size of tumours larger for regular users Significant disagreement between side of use and side of tumour Hearing loss may be a negative confounder presence of hearing problems prior to diagnosis may prevent cases from becoming regular users and limit their lifetime calling time IRPA 11 Plenary Panel Session 3 12