significance, on the digit symbol test of psychomotor performance, EEG records of sleep, event-related potential, visual evoked potential, and computerized posturography.
These conclusions are based on retrospective studies of three different exposed populations in which the acute cholinergic signs and symptoms were documented as an acute effect of exposure. The findings from those studies are based on comparisons with control populations. One population consisted of industrial workers accidentally exposed to sarin in the United States; the other two populations were civilians exposed during terrorism episodes in Japan. The health effects listed above were documented at least 6 months after sarin exposure, and some persisted up to a maximum of 3 years, depending on the study. Whether the health effects noted above persist beyond the 3 years has not been studied.
The committee concludes that there is inadequate/insufficient evidence to determine whether an association does or does not exist between exposure to sarin at low doses insufficient to cause acute cholinergic signs and symptoms and subsequent long-term adverse health effects.
On the basis of positive findings in a study of nonhuman primates and in studies of humans exposed to organophosphate insecticides (see Appendix E), it is reasonable to hypothesize the occurrence of long-term adverse health effects from exposure to low levels of sarin. Studies of low-level exposure of workers find that organophosphate insecticides are consistently associated with higher prevalence of neurological and/or psychiatric symptom reporting (see Appendix E). However, there are no well-controlled human studies expressly of sarin’s long-term health effects at doses that do not produce acute signs and symptoms.
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