Note : la ‘saga mélatonine’ continue. Cette publication montre que tout le monde n’est pas sensible aux CEM de la même façon et que les effets nocifs des CEM se traduisent dans les études épidémiologiques.
(Note et trad. R. GAUTIER)Am J Epidemiol 2001 Oct 1;154(7):601-9
Les effets de champs électriques et magnétiques de lignes hautes tension sur l'excrétion féminine urinaire de 6-sulfatoxymelatonin.
Effects of electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin.
Levallois P, Dumont M, Touitou Y, Gingras S, Masse B, Gauvin D, Kroger E, Bourdages M, Douville P.
Unite de recherche en sante publique, Pavillon CHUL, Centre hospitalier universitaire de Quebec, Quebec, Canada. patrick.levallois@msp.ulaval.ca
En 1998, les auteurs ont étudié l'effet d'exposition résidentielle aux champs électriques et magnétiques de hautes tensions sur l'excrétion féminine urinaire de 6-sulfatoxymelatonin (6-OHMS) dans la ville de Québec, Canada, en secteur métropolitain. Un échantillon de 221 femmes vivant près un 735-kV la ligne a été comparé avec 195 femmes du même âge vivant loin de n'importe quelles lignes à haute tension. Les participants ont fourni des échantillons d'urine du matin 2 jours consécutifs et ont porté un dosimètre magnétique pendant 36 heures consécutives pour mesurer l'exposition personnelle magnétique. Le champ intérieur électrique a été évalué par des ponctuelles. Après le réglage d'autres facteurs associés à la sécrétion basse mélatonine, comme l'utilisation de médication ou l'exposition légère, la concentration de nuit de 6-OHMS était semblable dans les deux groupes. Quand ou l'exposition de 24 heures ou l'exposition durant le sommeil aux champs magnétiques ou électriques a été utilisé, aucune relation d'effet d'exposition n'était évidente. Cependant, la tendance de diminuer la concentration de 6-OHMS avec l'âge a été plus prononcée pour des femmes vivant près des lignes, comme était inférieure la concentration de 6-OHMS chez des femmes avec un haut index de poids corporel. L'exposition chronique résidentielle aux champs magnétiques de lignes haute tension peut accentuer la diminution de la sécrétion de mélatonine observée dans quelques sous-groupes vulnérables de la population.
In 1998, the authors studied the effect of residential exposure to electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin (6-OHMS) in the Quebec city, Canada, metropolitan area. A sample of 221 women living near a 735-kV line was compared with 195 women the same age living away from any power lines. Participants provided morning urine samples on 2 consecutive days and wore a magnetic dosimeter for 36 consecutive hours to measure personal magnetic exposure. The indoor electric field was assessed by spot measurements. After adjustment for other factors associated with low melatonin secretion, such as medication use or light exposure, nighttime concentration of 6-OHMS was similar in the two groups. When either 24-hour or sleep-time exposure to magnetic field or electric field measurements was used, no exposure-effect relation was evident. However, the trend of decreasing 6-OHMS concentration with age was more pronounced for women living near the lines, as was a lower 6-OHMS concentration in women with high body mass index. Chronic residential exposure to magnetic fields from high-power lines may accentuate the decrease in melatonin secretion observed in some vulnerable subgroups of the population.
Et trouvé sur le net :
Residential Magnetic Fields, Light-at-Night, and Nocturnal Urinary 6-Sulfatoxymelatonin Concentration in Women.
S. Davis, W.T.Kaune, D.K. Mirick, C. Chen and R.G. Stevens
American Journal of Epidemiology Vol. 154, No. 7, 591-600; October 1st, 2001.
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Effects of Electric and Magnetic Fields from High-power Lines on Female Urinary Excretion of 6-Sulfatoxymelatonin.
P Levallois, M Dumont, Y. Touitou, S. Gingras, B. Masse, D. Gauvin, E. Kroger, M. Bourdages and P. DouvilleAmerican Journal of Epidemiology Vol. 154, No. 7, 601-609; October 1st, 2001
Two new reports in the latest issue of the American Journal of Epidemiology present evidence that domestic exposure to elevated levels of power frequency magnetic fields results in decreased production of melatonin. The effect appears to occur with only modestly increased level of magnetic field exposure, >0.2 microtesla (
T). Melatonin is a natural substance produced by the pineal gland principally at nigh time. Its ability to inhibit the promotion of cancer has been shown in animals and it has been shown to suppress the growth of breast cancer cells in-vitro. Reduced levels of melatonin in the body have also been associated with depression.The First Report is by Scot Davis et al:
"Residential Magnetic Fields, Light-at-Night, and Nocturnal Urinary 6-Sulfatoxymelatonin Concentration in Women"
S Davies et al, American Journal of Epidemiology Vol. 154, No. 7, 591-600; October 1st, 2001.
Abstract (main points): Exposure to 60-Hz magnetic fields may increase breast cancer risk by suppressing the normal nocturnal rise in melatonin. This 1994-1996 Washington State study investigated whether such exposure was associated with lower nocturnal urinary concentration of 6-sulfatoxymelatonin in 203 women aged 20-74 years with no history of breast cancer. The results suggest that exposure to night time residential 60-Hz magnetic fields can depress the normal nocturnal rise in melatonin.
The Second paper is by Levallois et al:
"Effects of Electric and Magnetic Fields from High-power Lines on Female Urinary Excretion of 6-Sulfatoxymelatonin"
P Levallois et al, American Journal of Epidemiology Vol. 154, No. 7, 601-609; October 1st, 2001.
Abstract (main points); The authors studied the effect of residential exposure to electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin (6-OHMS) in Quebec city, metropolitan area. A sample of 221 women living near a 735-kV (power) line was compared with 195 women the same age living away from any power lines. The authors report that a trend of decreasing 6-OHMS concentration with age was more pronounced for women living near the lines, as was a lower 6-OHMS concentration in women with high body mass. The authors conclude that chronic exposure to magnetic fields from high-power lines may accentuate the decrease in melatonin secretion observed in some vulnerable subgroups of the population.