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

[UMTS基地局RF放射との関連でみた成人と青年の認知機能および症状] med./bio.

Cognitive function and symptoms in adults and adolescents in relation to rf radiation from UMTS base stations.

掲載誌: Bioelectromagnetics 2008; 29 (4): 257-267

この研究は、ヒトの認知機能と症状に対するUMTS基地局から放射される無線周波電磁界ばく露の急性影響をボランティア実験で調べた。40人の若年者(15-16才)および40人の成人(25-40才)は、1) 擬似ばく露群、2) 2140MHzの連続波へのばく露群、3) UMTS信号を模擬した変調2140MHzばく露群、4) 2140MHzUMTS信号ばく露群の4つの条件のばく露(各45分間)を、無作為、二重ブラインド、クロスオーバデザインで与えられ、ばく露の間に、トレイルマーキングB(TMB)など数種の認知タスクと主観的症状調査票への回答を行った。その結果、UMTS群と擬似ばく露群の間にTMB成績の有意差はなかった;その他の認知タスクのどれでも有意な変化は見られなかった;若年と成人のデータを統合した場合、頭痛の評点の上昇が観察された、などを報告している。

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研究目的(著者による)

This study was designed to investigate the acute effects of radio frequency electromagnetic fields emitted by UMTS mobile phone base stations on human cognitive function and symptoms in vivo.

詳細情報

Adolescents (mean age: 15.7 years; 17 males, 23 females) and adults (mean age: 31.1 years; 24 males, 16 females), neurologically healthy were selected for this study. During exposure the participants performed different cognitive tasks (amongst others "Trail Making B" test) and completed a questionnaire measuring self reported subjective symptoms. In the applied "Trail Making B" test the participants had to draw lines alternating beween numbers and letters in consecutive order. The time at which the task was completed correctly was measured.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 2,140 MHz
Modulation type: CW
ばく露時間: continuous for 45 min
ばく露2: 2,140 MHz
ばく露時間: continuous for 45 min

General information

All participants attended four exposure sessions on separate days at the same time of day. They were exposed to four conditions: sham, CW, a signal modulated as UMTS, and UMTS including all control features in a randomized, double blinded cross-over design.

ばく露1

主たる特性
周波数 2,140 MHz
タイプ
  • electromagnetic field
偏波
  • linear
ばく露時間 continuous for 45 min
Additional information plane wave with vertical polarization
Modulation
Modulation type CW
ばく露装置
ばく露の発生源/構造
  • medium gain antenna
Distance between exposed object and exposure source 2.8 m
チャンバの詳細 The study was performed under controlled conditions in a shielded 33.4 m³ climate chamber made of aluminium with walls, floor, and ceiling partly covered with RF absorbers. All cables to and from the chamber were filtered and mounted with ferrite beads to suppress common mode signals. All lighting in the room was from light-fibres or from a 12 V DC source, and all electronic devices were supplied by 12 V DC.
ばく露装置の詳細 The participants were seated on a chair at a wooden table next to a computer and keyboard.
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電界強度 2.2 V/m maximum 測定値 - -
電界強度 1.5 V/m minimum 測定値 - limited area
電界強度 0.9 V/m minimum 測定値 - total area
電力密度 2.6 mW/m² - - - target value

ばく露2

主たる特性
周波数 2,140 MHz
タイプ
  • electromagnetic field
偏波
  • linear
ばく露時間 continuous for 45 min
Additional information plane wave with vertical polarization
Modulation
Modulation type cf. additional information
Additional information

a signal modulated as UMTS, or UMTS including all control features

ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
Distance between exposed object and exposure source 2.8 m
Additional information The CW modulated as UMTS was generated by setting the control channels to the lowest level (P-SCH, S-SCH, P-CCPCH, and the PICH channel). The UMTS signal was generated by initiating a live connection to a mobile phone through a 10 dB coupler and then filtering only the base station signal to the exposure antenna.
パラメータ
測定量 種別 Method Mass 備考
電界強度 2.2 V/m maximum 測定値 - -
電界強度 1.5 V/m minimum 測定値 - limited area
電界強度 0.9 V/m minimum 測定値 - total area
電力密度 2.6 mW/m² - - - target value

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:
研究対象とした臓器系:
調査の時期:
  • ばく露後

研究の主なアウトカム(著者による)

No statistically significant differences between the UMTS and sham exposure were found in any of the cognitive tests or self reported symptoms in both adolescents and adults.

研究の種別:

研究助成

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