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

[人の睡眠の質およびメラトニン周期に対する短波 (6-22 MHz)磁界の影響： シュワルツェンベルクにおける稼働停止研究] med./bio.

Effect of short-wave (6-22 MHz) magnetic fields on sleep quality and melatonin cycle in humans: the Schwarzenburg shut-down study

著者: Altpeter ES, Röösli M, Battaglia M, Pfluger D, Minder CE, Abelin T
掲載誌: Bioelectromagnetics 2006; 27 (2): 142-150
RISフォーマットで参考文献をダウンロード

この研究は、短波放送の送信機の一時稼働停止を利用した「自然の実験」の結果を報告している。1998年、Schwarzenburg（スイス）の短波放送送信機の一時稼働停止の前と後に、周辺の住民ボランティア54人（男性21、女性33）を対象に、停止前と後のそれぞれ1週間、次の調査を実施した。唾液のメラトニンは、唾液を1日5回採取し、毎日の分泌総量と頂点位相を推定した。睡眠の質は、毎日、視覚的アナログスケールによりスコアを自己申告させた。その結果、停止前では、自己申告による睡眠の質スコアは、磁界ばく露の増分mA/m毎に3.9点減少した(95% CI: 1.7-6.0)；それに対応してメラトニンの分泌総量が10%減少した(95% CI: -32 - 20%)；停止後では、自己申告による睡眠の質スコアは、磁界ばく露の低下mA/m毎に1.7点改善した(95% CI: 0.1-3.4)。メラトニン分泌量はベースライン値に比べ15％増加し（95% CI: -_3 - 36%) 、リバウンド効果と考えられた；層別分析では、睡眠の質スコアが低い人において、メラトニン分泌に対するばく露の影響が見られた一方、スコアの高い人では、そのような影響は見られなかった；睡眠の質スコアが低い人において、睡眠の質とメラトニン分泌量の変化の大きさは、送信機停止後の磁界の減少の大きさと関連していたが、スコアの高い人では、そのような影響は見られなかった；このような観察研究ではばく露のブラインド化が不可能であり、このことが直接、間接に測定結果に影響していた可能性がある、と報告している。

The detailed summary of this article is not available in your language or incomplete. Would you like to see a complete translation of the summary? Then please contact us →

研究目的（著者による）

This study describes the results of a unique "natural experiment" of the operation and cessation of a broadcast transmitter with its short wave electromagnetic fields (6-22 MHz) on sleep quality and melatonin cycle in a general human population sample.

詳細情報

In 1998, 54 volunteers were followed for one week each before and after shut-down of the short wave radio transmitter at Schwarzenburg (Switzerland).
Melatonin was sampled five times a day. Sleep quality was recorded daily.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 6.1–21.8 MHz
Modulation type: AM
ばく露時間: continuous, studied for 4 days before shutdown
  • 磁界強度: 0.4 mA/m mean (median = 0.40 mA/m, low exposure group)
  • 磁界強度: 2.6 mA/m mean (median = 2.1 mA/m, high exposure group)

ばく露1

主たる特性
周波数 6.1–21.8 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous, studied for 4 days before shutdown
Additional information reference article: Altpeter et al. 1995. Study on health effects of the shortwave transmitter station of Schwarzenburg, Berne, Switzerland. BEW (Bundesamt of Energiewirtschaft); 1995. BEW Publication Series No. 55.
Modulation
Modulation type AM
ばく露装置
ばく露の発生源／構造
  • shortwave transmitter with star shaped antenna
ばく露装置の詳細 The shortwave transmitter operated with a maximum power of two times 150 kW. The direction of the transmission beam changed about every 2 h according to the local time in the target areas (America, Asia, Africa, Australia). The beam was elevated by 11° above the horizontal.
パラメータ
測定量 値 種別 Method Mass 備考
磁界強度 0.4 mA/m mean 計算値 - median = 0.40 mA/m, low exposure group
磁界強度 2.6 mA/m mean 計算値 - median = 2.1 mA/m, high exposure group
Additional parameter details

Before shut down of the transmitter H-field exposure of the study population was in the range of 0.2 to 6.7 mA/m (mean 1.5 mA/m, median 0.92 mA/m). The study population was divided in two groups according to median exposure value. Average exposure level in the low exposure group was 0.4 mA/m (median = 0.40 mA/m), in the high exposure group 2.6 mA/m (median = 2.1 mA/m). After shut-down, there were no emission sources left in this frequency range.

測定および計算の詳細

An isotropic sensor system was used that took continuous measurements in a hayloft of a cattle stable which was located 925 m north of the shortwave transmitter's star shaped antenna, for the whole study period. The probe had been previously validated and reported (see reference article). 24 h average H field exposure [mA/m] was calculated by Swisscom for each subject's home using Maxwell equations, taking into account the relative position of the residencies to the centre of the antenna (azimuth and distance), the previous exposure measurements (1992, 1993, 1996), and the present broadcasting scheme.

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
  • ばく露後

研究の主なアウトカム（著者による）

During operation of the transmitter self-rated morning freshness as an indicator of sleep quality decreased with increasing exposure to short-wave electromagnetic fields. The authors revealed that sleep quality improved after the transmitter shut-down, and they found evidence suggestive of a rebound in nightly melatonin excretion in poor sleepers. The authors did not find any acute or chronic effects of exposure on the acrophase (peak time of melatonin excretion) of the melatonin cycle.
Due to the observational nature of the study, a direct biological cannot, however, have been causality proven, and the possibility of a psychological rather than a biological effect cannot be excluded. From a public health perspective these results call for caution in exposing populations to electromagnetic fields from short wave radio transmitters.

研究の種別:

研究助成

関連論文