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

[高調波ならびに過渡成分を持つ50 Hz磁界への急性ばく露: ヒトでの夜間ホルモン分泌への影響はない] med./bio.

Acute exposure to 50 Hz magnetic fields with harmonics and transient components: Lack of effects on nighttime hormonal secretion in men

掲載誌: Bioelectromagnetics 2003; 24 (1): 12-20

この研究は、居住環境中で遭遇する低周波および中間周波磁界MF)を人工的に作成し、その実験的ばく露により、ホルモン(特にメラトニン)の夜間分泌が影響を受けるか否かを、ヒトボランティア実験で調べた。被験者は10人の健康な男性である。被験者は、実験のために、間をおいて2夜、実験室(3軸メリットコイルを備えた、1辺2.7 mの立方体)内に滞在した。1夜は、直線偏波の50 Hz、20 μTの正弦波磁界(3次(30%)および5次(10%)高調波および反復性の過渡波(1 kHzのバースト波(1バースト/秒、ピーク振幅100 μT、持続時間50 msで指数関数的減衰)を含む)のばく露に用い、別の1夜は、ブラインドコントロールに用いた。血液サンプルの採取は、夜間(睡眠時間2300-0700を含む2000-0800)は1時間間隔で行い、特に2200-0200の間は10分間で行なった。前者の試料は、血漿ホルモンメラトニン成長ホルモン(GH)、コルチゾールプロラクチン)のレベル測定、後者は、睡眠誘発されるGHサージの観察に用いた。その結果、4つのホルモンのプロファイルには、2夜の間に有意差はなかった、と報告している。

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研究目的(著者による)

The effects of exposure of subjects to a 50 Hz and intermediate frequency magnetic field on the nighttime blood plasma levels of melatonin and other hormones should be investigated.

詳細情報

10 male subjects participated in the study and each attended 3 night sessions (but only samples from 9 subjects were analyzed). The first session was for habituation to the experimental conditions, the other 2 sessions were for exposure or sham exposure, respectively, with the order being unknown to the subjects.
Blood samples were automatically collected every hour during exposure and sham exposure in general and every 10 minutes between 22.00 and 02.00 o'clock.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz–1 kHz
ばく露時間: continuous for 12 h (20.00 to 08.00 o'clock)

ばく露1

主たる特性
周波数 50 Hz–1 kHz
タイプ
  • magnetic field
波形
  • sinusoidal
偏波
  • linear
ばく露時間 continuous for 12 h (20.00 to 08.00 o'clock)
Additional information the following components were superimposed on the primary 50 Hz field: third harmonics with 30% intensity of primary field (effective value) fifth harmonics with 10% intensity of the primary field (effective value) 1 kHz with initial 100 µT (peak) field, which attenuated exponentially over a duration of 50 ms and repeated at 1 s intervalls (1 burst/s)
ばく露装置
ばく露の発生源/構造
チャンバの詳細 the exposure room had a dual structure with an inner room (cube with 2.7 m side length) being completely enclosed within a larger outer room (cube with 4 m side length); frame for room was made of wood; interior resembled a small room of a house with textured walls, equipped with a small table and a bed
ばく露装置の詳細 4 coil-square loop configuration with 3-axis Merritt coils; the outer two coils had 16 turns each and the inner coils had 8 turns; coils were located in the space between the inner and outer rooms; the coils were set in the same manner in each of the three dimensions of the room except that the horizontal inner coils were wound around the door; all of the windings were formed with a twisted pair of copper wires; temperature was maintained at ± 1°C and relative humidity at ± 5%; room was not shielded from intruding fields; direction of the field coincided with the longer axis of the bed
Sham exposure A sham exposure was conducted.
Additional information sham exposure conditions were set by changing the current direction in one of the pair of wires of the coil
パラメータ
測定量 種別 Method Mass 備考
磁束密度 20 µT - 測定値 - for the 50 Hz field
磁束密度 100 µT peak 測定値 - initial value of the 1 kHz field

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:
研究対象とした臓器系:
調査の時期:
  • ばく露中

研究の主なアウトカム(著者による)

All hormones showed time-dependent variabilities in their concentrations over the investigation period, which corresponded to typical physiological rhythms. However, no significant differences were found between exposure and sham exposure conditions.
The authors conclude that exposure of subjects to a 50 Hz and intermediate frequency magnetic field shows no effects on the nighttime blood plasma levels of melatonin and other hormones.

研究の種別:

研究助成

関連論文