Environmental clinics are frequented by patients with fears and complaints related to environmental triggers. A dose-independent overreaction to small doses of widely used and generally non-toxic chemicals is referred to as multiple chemical sensitivity (MCS), but no clearly defined clinical syndrome with objective physical findings has been delineated so far. We aimed to obtain information about symptoms, supposed environmental triggers, the frequency of self-reported chemical sensitivity, and of the diagnosis MCS in Germany.
We conducted a representative survey among 2032 adult Germans.
We found self-reported chemical sensitivity in 9% and physician-diagnosed MCS in 0.5% of our representative sample. Physical complaints were common in the whole study population and in chemically sensitive individuals, but there was no clear-cut symptom constellation among the latter. The most common complaints were headache, fatigue, sleep disturbances, joint pain, mood changes and nervousness. A subjective connection between complaints and environmental triggers was denied by 67% of the whole group and by 35% of the self-reported chemically sensitive. Factor analysis of environmental triggers suggested that a specific exposure situation rather than chemical similarity is the basis for individual trigger combinations.
The prevalence of subjective sensitivity towards chemicals is similar to such rates reported from other countries. There is a relatively low awareness of the MCS-concept, and it appears to be diagnosed less frequently than, e.g., in the USA. Since symptoms and triggers in chemically sensitive individuals did not differ from the general population, our data do not suggest the existence of a widespread new syndrome related to chemical sensitivities in Germany. We outline the limitations of self-reported chemical sensitivity as the major criterion for such a contentious diagnosis as MCS.
"In Sweden 15.6% of teenagers reported chemical sensitivity  , and 33% of adults reported being bothered by strong odors, while 19% had made behavioral changes as a result  , In The Netherlands 45% of persons reported problems with at least one chemical and 27% from multiple chemicals  . A German study found that 32% of persons blamed their health concerns on and 11% reported immediate reactions from chemical exposure  . Meggs and colleagues  in the US found that 4% of a rural representative household sample reported illness from chemicals on a daily basis with one third of respondents reporting some illness from exposures to chemicals. "
[Show abstract][Hide abstract] ABSTRACT: Life indicators, illness characteristics, and psychosocial concomitants were measured in a large sample of persons self-reporting multiple chemical sensitivity. Cross-sectional data are presented for 305 persons who responded to written surveys. Examined are employment status, income, relationship status, illness characteristics such as length, severity, and age respondents became sensitive, money spent on physicians and on home alterations, situations reported to cause the initial sensitization, and the psychosocial measures of social support and psychosocial adjustment to illness. In addition, relevant life indicators are re-examined two years later and presented for 209 persons who continued to participate. This paper examines life indicators for persons of four levels of severity of condition and three courses of condition over time.
"A substantial proportion of the general population experience debilitating symptoms after being exposed to everyday chemicals at low concentrations assumed to be harmless  . Unlike known toxicological effects of chemicals, the etiology of such self-reported chemical intolerance (CI) is unknown. "
[Show abstract][Hide abstract] ABSTRACT: Objective:
Idiopathic environmental intolerance (IEI) to smells is a prevalent medically unexplained illness. Sufferers attribute severe symptoms to low doses of non-toxic chemicals. Despite the label, IEI is not characterized by acute chemical senses. Theoretical models suggest that sensitized responses in the limbic system of the brain constitute an important mechanism behind the symptoms. The aim was to investigate whether and how brain reactions to low-levels of olfactory and trigeminal stimuli differ in individuals with and without IEI.
Brain responses to intranasally delivered isoamyl acetate and carbon dioxide were assessed in 25 women with IEI and 26 non-ill controls using functional magnetic resonance imaging.
The IEI group had higher blood-oxygenated-level-dependent (BOLD) signal than controls in the thalamus and a number of, mainly, parietal areas, and lower BOLD signal in the superior frontal gyrus. The IEI group did not rate the exposures as more intense than the control group did, and there were no BOLD signal differences between groups in the piriform cortex or olfactory regions of the orbitofrontal cortex.
The IEI reactions were not characterized by hyper-responsiveness in sensory areas. The results can be interpreted as a limbic hyperreactivity and speculatively as an inability to inhibit salient external stimuli.
Journal of Psychosomatic Research 10/2014; 77(5). DOI:10.1016/j.jpsychores.2014.09.014 · 2.74 Impact Factor
"Avoiding exposure to potential symptom-eliciting chemicals is a characteristic coping response in affected individuals, which includes avoiding public places and transportation , restricting social activities, and occupational considerations (Gibson et al., 2003). The prevalence of self-reported chemical sensitivity symptoms in populationbased studies ranges from 9% to 33% (Hausteiner et al., 2005; Johansson et al., 2005; Berg et al., 2008), whereas physiciandiagnosed MCS or reports of disabling consequences in the form of social and occupational disruptions are much lower, ranging from 0.5% to 6.3% (Berg et al., 2008; Kreutzer et al., 1999; Caress and Steinemann, 2003). There are currently no internationally accepted consensus criteria for MCS (Graveling et al., 1999; Das-Munshi et al., 2007); consequently, the diversity of applied case definitions in the scientific literature is high. "
[Show abstract][Hide abstract] ABSTRACT: Background
Multiple chemical sensitivity (MCS) is a medically unexplained condition characterized by reports of recurrent unspecific symptoms attributed to exposure to low levels of common volatile chemicals. The etiology of MCS is poorly understood, but dysregulation of the immune system has been proposed as part of the pathophysiology.
To compare plasma levels of cytokines in Danish MCS individuals with a healthy, sex- and age-matched control group.
Blood samples were obtained from 150 un-exposed MCS individuals and from 148 age- and sex-matched healthy controls. Plasma concentrations of 14 cytokines, chemokines and growth and allergen-specific IgE were measured. All participants completed a questionnaire including questions on MCS, psychological distress, morbidities and medication use at the time of the study.
Plasma levels of interleukin-1β, -2, -4, and -6 were significantly (P < 0.001) increased in the MCS group compared with controls, tumor necrosis factor-α was borderline significantly (P = 0.05) increased and interleukin-13 was significantly decreased (P < 0.001).
MCS individuals displayed a distinct systemic immune mediator profile with increased levels of pro-inflammatory cytokines and interleukin-2 and inverse regulation of Th2 associated cytokines interleukin-4 and interleukin-13 suggestive of low-grade systemic inflammation, along with a deviating Th2-associated cytokine response not involving IgE-mediated mechanisms.
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