title: Idiopathic environmental intolerance: Part 1: A causation analysis applying Bradford Hill's criteria to the toxicogenic theory.
abstract: Idiopathic environmental intolerance (IEI) is a descriptor for a phenomenon that has many names including environmental illness, multiple chemical sensitivity and chemical intolerance. Toxicogenic and psychogenic theories have been proposed to explain IEI. This paper presents a causality analysis of the toxicogenic theory using Bradford Hill's nine criteria (strength, consistency, specificity, temporality, biological gradient, biological plausibility, coherence, experimental intervention and analogy) and an additional criteria (reversibility) and reviews critically the scientific literature on the topic. The results of this analysis indicate that the toxicogenic theory fails all of these criteria. There is no convincing evidence to support the fundamental postulate that IEI has a toxic aetiology; the hypothesised biological processes and mechanisms are implausible.
authors.affiliation: Behavioral Medicine, Multi-Disciplinary Toxicology, Treatment and Research Center, Denver, Colorado 80222, USA. hstaudenmayer@comcast.net
authors.forename: Herman
authors.initials: H
authors.lastname: Staudenmayer
authors.forename: Karen E
authors.initials: KE
authors.lastname: Binkley
authors.forename: Arthur
authors.initials: A
authors.lastname: Leznoff
authors.forename: Scott
authors.initials: S
authors.lastname: Phillips
mesh_terms: D000818:Animals; D015984:Causality; D004781:Environmental Exposure / Q000009:adverse effects*; D019317:Evidence-Based Medicine; D006801:Humans; D018777:Multiple Chemical Sensitivity / Q000453:epidemiology / Q000209:etiology; D017891:Pharmacoepidemiology / Q000379:methods*; D014116:Toxicology / Q000379:methods*