TNO study design & results

Transcription

1 TNO study design & results Eric van Rongen WHO International EMF Project IAC meeting Istanbul, June 2004

2 Study population in the Netherlands exists the Monitoring Network on Health and Environment non-profit profit,, non-governmental volunteer organisation registry of people with complaints they attribute to living near (base station) antennas interesting study population

3 Exposure initial idea: exposure to GSM cellphone-like like fields sensitive subjects, therefore: base-station station-like field strength

4 Study goal determine causal relation between EMF exposure and subjective symptoms assess cognitive performance during EMF exposure

5 Experimental design exposure in shielded (anechoic) room conditions: 900 MHz GSM-fields 1800 MHz GSM-fields 2100 MHz UMTS-like fields sham 4 sessions of max 45 min, ~30 min interval: 1st: training session (no exposure) 2nd-4th: exposure sessions, randomized 1 sham 2 actual exposure

6 Experimental setup control computer signal generator antenna monitor probe 3 m TFT monitor HP E4433B amplifier 1,5 m CK8 Taskomat anechoic room

7 Antenna monitoring probe UMTS GSM

8 Taskomat setup

9 Exposure conditions field strengths chosen: maximum value measured occasionally in living environment (1 V/m) peak field strength is maximized effective field strength: GSM: 1.0 V/m UMTS: 0.7 V/m

10 Subjects Volunteers with subjective complaints (36; group A) recruited through Monitoring Network on Health and Environment very reluctant to participate Volunteers without complaints (36; group B) own TNO network local newspaper Internet Result: unbalanced groups

11 Subjects (cont.) y no history of brain injury, epilepsy, claustrophobia not treated for mental disease in past 6 months not treated with psycho-active drugs in past 2 weeks no pacemaker or hearing aid no coffee / tea 6 h before start of study

12 Protocol - questionnaires questionnaire before test session Big 5 (personality) well-being: questionnaire before & after sessions subset from Bulpitt questionnaire full questionnaire validated for hypertension contains for present study irrelevant questions Ethical Committee demanded use of subset

13 Protocol cogn. functions cognitive function tests: simple reaction time memory task visual selective attention task auditive selective function task tracking task

14 Hypothesis there is no statistically significant difference in subjective symptoms and cognitive functions between sham exposure and GSM 900, GSM 1800 or UMTS-like exposure

15 Well-being: sumscores Mean sumscore + SEM p= Correction for multiple comparisons: α=0.017 p= S E S E S E S E S E S E Group A Group B

16 Overview of cognitive function tests Group A Group B GSM900 GSM1800 UMTS-like GSM900 GSM1800 UMTS-like Cognitive function test Reaction time Memory comparison Visual selective attention Dual tasking, reaction time Filtering irrelevant information No correction for multiple comparisons: α = 0.05 Correction for multiple comparisons, (correlation 0.4): α = 0.01

17 Mechanism? cognitive functions other studies have found similar results for exposure using hand helds statistically significant changes in cognitive functions were attributed to thermal effects that might occur locally well-being: no positive responses reported sofar question: can thermal effects explain present results?

18 2100 MHz, side illumination 100 x= y #v ox els z #voxels SAR [mw/kg] 0.000

19 Calculations SAR for plane wave exposure with 1 V/m Frequency (MHz) Exposure Local SAR (mw/kg) Total SAR (nw/kg) 900 Side Side Side Front * Average over 10 g tissue

20 Mechanism? effects are highly unlikely to be caused by thermal effects

21 Validity questionnaire original Bulpitt questionnaire validated for long- term effects in hypertension study question: is presently used subset valid for short-term term effects of EM fields? no answer possible without further study

22 Conclusions null hypothesis ( no( relation ) ) is rejected statistically significant relations are found between RF-exposure and measured parameters consistent effect only on well-being validity of questionnaire questionable: should be checked thermal effects seem highly unlikely to explain results

23 Conclusions (cont.) WHO definition of health includes well-being: effect on well-being = effect on health present study: the first one with this setup replication necessary Swiss group will replicate (UMTS, 1 & 10 V/m) follow-up studies necessary many parameters can be varied study design can be improved

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25 Well-being questionnaire Questions (first 10 out of 23) Feeling dizzy or faint Feeling tired or a lack of energy Nervous Feelings of pressure or tightness in head or body Scared or frightened Heart beating quickly or strongly without reason (throbbing or pounding) Feeling that there was no hope Restless or jumpy Poor memory Chest pains or breathing difficulties or feeling of not having enough e air

26 Well-being questionnaire (cont.) answers possible not at all score: 0 a little, slightly score: 1 a great deal, quite a bit score: 2 extremely, could not have been worse score: 3

27 Well-being: individual questions gr. A 1,0 Mean scores of individual questions of well-being questionnaire Group A * 0,8 * Mean score 0,6 0,4 * * * * * 0,2 * 0,0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 Q19 Q20 Q21 Q22 Q23 Question * p<0.05 Placebo 900MHz 1800MHz 2100MHz

28 Well-being: individual questions gr. B 1,0 Mean scores of individual questions of well-being questionnaire Group B 0,8 Mean score 0,6 0,4 0,2 * 0,0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 Q19 Q20 Q21 Q22 Q23 Question * p<0.05 Placebo 900MHz 1800MHz 2100MHz