CHEMICAL-SENSITIVITY ATTRIBUTED TO PESTICIDE EXPOSURE VERSUS REMODELING

One hundred twelve individuals who reported onset of multiple chemical sensitivity following well-documented exposure to either (1) a cholin esterase-inhibiting organophosphate or carbamate pesticide or (2) remo deling of a building completed mailout/mail-back questionnaires concer ning their exposure, symptoms, sensitivity to ingestants and inhalants , utilization of health-care resources, and impact of their illness on lifestyle. it was hypothesized that if multiple chemical sensitivity resulted from neurotoxic exposure, then organophosphate-exposed respon dents should report greater severity of illness resulting from the rel atively greater neurotoxicity of this class of chemicals. Pesticide-ex posed and remodeling-exposed multiple chemical sensitivity groups repo rted similar patterns of symptoms and identified similar inhalants and ingestants as triggers for their symptoms; these results suggested a common mechanism (biological and/or psychological) for their condition s. The pesticide-exposed group, however, reported significantly greate r symptom severity than did the remodeling-exposed group, especially f or neuromuscular, affective, airway, gastrointestinal, and cardiac sym ptoms. These findings provide evidence for (1) a possible biological b asis for multiple chemical sensitivity and (2) a distinct pathophysiol ogy or final common pathway for the condition that, while as yet undef ined, appears to be shared by these two groups. Although subjective mu ltisystem health complaints characterize both multiple chemical sensit ivity and somatoform disorder, features of this multiple chemical sens itivity sample were inconsistent with somatoform disorder, i.e., onset after 30 y of age in 83%, the predominance of severe cognitive sympto ms, and attributions of environmental causation. No group differences were found with respect to lifestyle impact. Eighty-one percent of res pondents said they had been working full-time at the time they were ex posed, yet at the time of the survey (on average, 7.7 y post exposure) only 12.5% were working full-time. The majority said they had quit th eir jobs, changed jobs, or changed careers because of their illness. A pproximately 40% reported that they had consulted 10 or more medical p ractitioners. The persistent, disabling neuropsychological symptoms re ported by these multiple chemical sensitivity groups are strikingly si milar to those reported among individuals exposed occupationally to pe sticides and solvents. These parallel findings suggest that the types and levels of exposures associated with extermination and remodeling m ay not be inconsequential, at least for a subset of the population. Fu rther studies from a variety of perspectives, including human challeng e studies and the development of animal models, are needed to define t he pathophysiological and psychological mechanisms underlying this cos tly condition.