研究のタイプ: 医学／生物学の研究 (experimental study)

[884 MHzGSM無線通信信号が頭痛および他の症状に及ぼす影響：誘発実験研究] med./bio.

The effects of 884 MHz GSM wireless communication signals on headache and other symptoms: an experimental provocation study

著者: Hillert L, Akerstedt T, Lowden A, Wiholm C, Kuster N, Ebert S, Boutry C, Moffat SD, Berg M, Arnetz BB
掲載誌: Bioelectromagnetics 2008; 29 (3): 185-196
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【背景】携帯電話使用による健康影響および生理学的影響に関する先の研究の知見は一致していない。誘発研究のばく露時間はやや短く、参加者の個人的特性は十分に明らかではなかった。【目的】携帯電話使用に起因すると自身は信じる症状を自己申告する被験者を含む調査グループにおいて長時間ばく露の後、RFの影響として自ら申告する症状および電磁界の感知について調べること。【方法】研究デザインは、二重盲検および交差法である。GSMハンドセットでのばく露および擬似ばく露を3時間行った。調査グループは18-45歳の71人であり、症状群（携帯電話使用に関連した頭痛やめまいの申告がある）38人、非症状群33人である。症状は７点リカットスケールを用いて、ばく露前、ばく露開始から1時間30分後（ばく露中間時点）および2時間45分後（ばく露終了時点）に評点された。被験者には自分の考えるばく露状況を報告させた。【結果】頭痛は、疑似ばく露時に比べ、RFばくろ時に申告が多かった。主に非症状群での増加によるものであった。RFばく露の感知は、両群ともに、偶然より高い確率では起きなかった。RFばく露中であると思うことは皮膚症状に関連した。非症状群においてRFばく露終了時点に向かって頭痛の頻度が高くなったことについては生理学的な関連因子の可能性を調べる必要がある。

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研究目的（著者による）

To study whether exposure to radiofrequency caused by cell phone use has any acute effect on self-reported symptoms (e.g. headache, vertigo) and whether subjects are able to accurately detect the correct exposure status (exposure vs. sham exposure).

詳細情報

The study group consisted of 71 subjects (age 18-45) including 38 subjects reporting headache or vertigo in relation to cell phone use (symptom group) and 33 non-symptomatic subjects (control group).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 884 MHz
Modulation type: pulsed
ばく露時間: continuous for 3 h
  • SAR: 1.4 W/kg average over time (10 g) (spatial peak for all head tissues)
  • SAR: 1.8 W/kg average over time (1 g) (spatial peak for grey matter)
  • SAR: 0.2 W/kg average over mass (brain) (± 0.26 W/kg grey matter)
  • SAR: 0.18 W/kg average over mass (brain) (e: ± 0.21 W/kg white matter d: ± 0,21 W/kg weiße Substanz)
  • SAR: 0.18 W/kg average over mass (brain) (± 0.06 W/kg thalamus)

General information

The study followed a double blind, cross-over provocation design testing exposure versus sham. The exposure setup was designed to expose all those head tissues that are exposed in daily phone usage, taking into account the range of phone designs, reasonable phone positions and head anatomies [Kuster et al., 2004], and the exposure was also intended to provide a similar tissue specific exposure distribution as applied by Huber et al. [2002].

ばく露1

主たる特性
周波数 884 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 3 h
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Additional information

The GSM signal with a basic frame of 4.6 ms consisted of temporal changes between non-DTX and DTX modes and included all coherent ELF amplitude modulation components of 2, 8, 217, and 1736 Hz.
ばく露装置
ばく露の発生源／構造
  • stacked micro patch antenna
チャンバの詳細 Two subjects participating in each session were seated in two adjacent unshielded rooms (5.1 m x 3.6 m and 5.1 m x 2.5 m, respectively) with RF absorbers placed on three sides. The exposure conditions were set to be the same for both participants during a session in order to avoid an influence of any possible leakage of fields.
ばく露装置の詳細 The exposure apparatus consisted of a balanced headset positioning a low-weight, stacked micro patch antenna on the left side of the subject's head.
Sham exposure A sham exposure was conducted.
Additional information To mimic the sensation caused by the active phone, a small ceramic plate connected to the left ear lobe was heated to 39 ± 0.2 °C by a laser during all exposure sessions.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 1.4 W/kg average over time 測定値および計算値 10 g spatial peak for all head tissues
SAR 1.8 W/kg average over time 測定値および計算値 1 g spatial peak for grey matter
SAR 0.2 W/kg average over mass 測定値および計算値 brain ± 0.26 W/kg grey matter
SAR 0.18 W/kg average over mass 測定値および計算値 brain e: ± 0.21 W/kg white matter d: ± 0,21 W/kg weiße Substanz
SAR 0.18 W/kg average over mass 測定値および計算値 brain ± 0.06 W/kg thalamus
Additional parameter details

The non-DTX mode with every 26th basic frame idle was set to a 10-g averaged peak spatial SAR (psSAR10g) of 1.95 W/kg. The DTX mode active during listening resulted in a reduced time-averaged psSAR10g of only 12% of the non-DTX mode. The temporal change was random with an average duration of 11 s for non-DTX and 5 s for DTX resulting in a time-averaged psSAR10g of 1.4 W/kg.

測定および計算の詳細

Numerical dosimetry was conducted with SEMCAD software and verified by measurements using DASY4 and the latest probe technology on a SAM head filled with tissue simulating liquid. Detailed dosimetric results were obtained following the methodology outlined in [Kuster et al., 2006]. In addition, the inter-subject variations as well as assessment uncertainty were estimated. The basic numerical head model was derived from 121 magnetic resonance images of a 40-year European female and distinguished 23 tissues.

Reference articles

ばく露を受けた生物:

方法 影響評価項目／測定パラメータ／方法

研究対象とした生物試料:
調査の時期:
  • ばく露前
  • ばく露中

研究の主なアウトカム（著者による）

The data showed that headache was more commonly reported after exposure than sham exposure, mainly due to an increase in the non-symptom group (control group).
Neither group could detect radiofrequency exposure better than by chance.
A belief that the radiofrequency irradiation had been active was associated with skin symptoms.
Further investigation of the higher prevalence of headache in the non-symptom group and a possible physiological correlation should be performed.
The findings indicate a need to better characterize subjects in cell phone exposure studies and differences between symptom and non-symptom groups.

研究の種別:

研究助成

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