• There is convincing evidence in animals of neurobehavioral responses to strong 60-Hz electric fields; however, adverse neurobehavioral effects of such fields have not been shown.

    Laboratory evidence clearly shows that animals can detect and respond behaviorally to electric fields. Evidence of behavioral responses in animals to ac magnetic fields is much more tenuous. In either case, general adverse behavioral effects have not been shown.

  • There is evidence of neuroendocrine changes associated with 60-Hz magnetic-field exposure in animals; however, alterations in neuroendocrine functions have not been shown to cause adverse health effects.

    The majority of studies that investigated magnetic-field effects on pineal-gland function suggest that these fields might inhibit night-time pineal and blood melatonin concentrations; in those studies, the effective field strengths varied from 10 µT (0.1 G) to 5.2 mT (52 G). The data supporting an effect of sinusoidal electric fields on melatonin production are not compelling. Other than the observed changes in pineal function, an effect from magnetic-field exposure on other neuroendocrine or endocrine functions has not been clearly shown in the few studies reported.

    Despite the observed reduction in pineal and blood melatonin concentrations in animals as a consequence of magnetic-field exposure, no evidence to date shows that melatonin concentrations in humans are affected similarly. In animals in which melatonin changes were seen, no adverse health effects have been found to be associated with electric-or magnetic-field-related depression in melatonin.

  • There is evidence that pulsed magnetic-field exposures greater than about 0.5 mT (5 G) are associated with bone-healing responses in animals.

    Replicable effects have been clearly shown in the bone-healing response of animals exposed to electric and magnetic fields at sufficiently high field strengths.

CRITERIA FOR CONSIDERATION OF LITERATURE

Consistent with the review guidelines established by the committee, only peer-reviewed literature is considered in this report unless otherwise noted. Results are reported only if they are exposure related and are statistically significant according to the authors' criteria unless otherwise noted. Greatest weight is given to studies that were confirmed in some manner in the peer-reviewed literature and that were blinded studies.

USE OF ANIMAL STUDIES IN EVALUATING RISK

Data from animal studies are an important component of estimating risk from nearly all agents. A gradient in the degree of an association between exposure to a toxic agent and the effects that agent can produce is called the dose-response relationship. The dose-response relationship forms the basis for the science of



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