Self-reported Chemical Intolerance Research Articles

Associations between symptoms, modern health worries, and somatosensory amplification in patients with building-related symptoms

ObjectiveThe objective of the present study was to investigate the associations between somatosensory amplification, modern health worries (MHWs), and symptoms among patients with building-related symptoms (BRS). MethodsPatients with self-reported and medically confirmed BRS (n = 83) were included in this cross-sectional study. The Somatosensory Amplification Scale (SSAS) was used to quantify the tendency to amplify somatic sensations and perceive them as unpleasant and dangerous. Concerns about harmful effects of modern technologies were assessed with the Modern Health Worries Scale (MHWS). Symptoms commonly found in different forms of environmental intolerance were assessed with the Environmental Hypersensitivity Symptom Inventory (EHSI). ResultsPatients with BRS were characterized by more frequent and more severe environmental hypersensitivity symptoms compared to a reference population. Females and those with co-morbid self-reported chemical intolerance reported even more symptoms. MHWS and SSAS scores showed weak to moderate associations with symptoms, even after adjusting for socio-economic variables. However, neither the mean MHWS score or the SSAS score of our sample differed from normative scores. ConclusionPatients with BRS are not characterized by elevated levels of MHWs and somatosensory amplification, thus other, psychosocial and/or environmental, factors may have contributed to the development of the condition. However, the associations between severity of symptoms and MHWs and somatosensory amplification suggest that psychosocial characteristics may substantially influence symptom experience in this group.

The Brief Environmental Exposure and Sensitivity Inventory (BREESI): an international validation study

BackgroundChemical intolerance (CI) is a condition that may result in multisystem symptoms triggered by low levels of exposure to xenobiotics such as chemical inhalants, foods, and/or drugs. The population prevalence of self-reported chemical intolerance is estimated to be between 4 and 25% across several countries. Clinicians and researchers require a brief, practical screening tool for identifying chemical intolerance.ObjectivesWe investigated the validity of a three-item screening questionnaire for CI, the Brief Environmental Exposure and Sensitivity Inventory (BREESI). The internationally validated, and widely used 50-item Quick Environmental Exposure and Sensitivity Inventory (QEESI) was used as the reference standard.MethodsFive thousand individuals (n = 1000 in each of five countries: the US, Japan, Italy, Mexico, and India) responded to both the QEESI and the BREESI using an online research survey platform. We determined the statistical performance metrics for the BREESI, comparing the number of items chosen on the BREESI with QEESI scores for chemical intolerance. Logistic regression was used to determine the likelihood of chemical intolerance based on endorsing 0, 1, 2, or 3 items on the BREESI. We report the BREESI's sensitivity and specificity, positive and negative predictive values, and positive and negative likelihood ratios.ResultsCompared to the QEESI reference standard, the BREESI had excellent sensitivity, specificity, positive and negative likelihood ratios, and positive and negative predictive values for chemical intolerance in all countries except than in Japan, the negative predictive value was poor. Notwithstanding, logistic regression curves show that in all of the countries, for each one-unit increase in the number of BREESI items, there is a 4- to 5-fold increase in the odds of CI.DiscussionThis study confirms the results of two recently published validation papers in the US. The BREESI performs well as a screening tool for chemical intolerance. It is a practical screening tool for researchers, clinicians, and epidemiologists seeking to understand and address this important and prevalent condition.

Chemical Intolerance Is Associated With Altered Response Bias, not Greater Sensory Sensitivity.

Chemical intolerance is a surprisingly prevalent condition or affliction characterized by adverse reactions to low levels of chemical, often odorous stimulation. Sufferers often assume that their plight is due to an uncommon sensory acuteness, yet studies repeatedly fail to reveal altered detection thresholds. Here, we investigated whether self-reported chemical intolerance is associated with altered sensory sensitivity or response bias. The sensory acuity (sensitivity; A) and sensory decision rule (criterion; B) to n-butanol was assessed using the method of constant stimuli in 82 participants with different degrees of chemical intolerance (low to high). Higher self-reported chemical intolerance was associated with a lower criterion, but not with sensitivity.

Factors affecting self-reported chemical intolerance: A five-year follow-up study in Japan

ObjectiveChemical intolerance (CI) has become a strong public health concern in industrialized countries. The Japanese Chemical Intolerance (JCI) study was conducted in January 2012 with a cohort of 7245 adults from population-based sampling as the baseline. The aim of the present study was to investigate the factors involved in the improvement and development of CI from the five-year follow-up study. MethodsFrom the 7245 cohort, 735 persons with CI (case) were identified, and 1750 controls without CI were randomly selected to match gender and age for case and control groups. Self-reported questionnaires were administered to the subjects of the two groups to obtain information on status of CI; medical history; medical, lifestyle, or physical interventions; changes in living situation or occupation; and psychosomatic states. ResultsA total of 909 individuals responded during the follow-up period. After five years, improvement in CI was observed in 67.7% of the case group. Status of CI was reported in 6.7% of the control group. Multiple logistic regression analyses revealed that baseline atopic dermatitis and negative psychosomatic states including irritability, fatigue, anxiety, depressed mood, and somatic symptoms were significantly associated with development of CI in controls. Appropriate physical activity and maintaining a regular lifestyle including diet or sleep during the last three years of the follow-up period were significant factors for improvement of CI in the case group. ConclusionsEnsuring appropriate physical activity and regular lifestyle rather than improving physical environment lead to improvement of CI. Stable psychosomatic state is essential for preventing CI.

Short-term olfactory sensitization involves brain networks relevant for pain, and indicates chemical intolerance.

Chemical intolerance is a medically unexplained affliction that implies deleterious reactions to non-toxic everyday chemical exposure. Sensitization (i.e. increased reactivity to repeated, invariant stimulation) to odorous stimulation is an important component in theoretical explanations of chemical intolerance, but empirical evidence is scarce. We hypothesized that (1) individuals who sensitize to repeated olfactory stimulation, compared with those who habituate, would express a lower blood oxygenated level dependent (BOLD) response in key inhibitory areas such as the rACC, and higher signal in pain/saliency detection regions, as well as primary and/or secondary olfactory projection areas; and (2) olfactory sensitization, compared with habituation, would be associated with greater self-reported chemical intolerance. Moreover, we assessed whether olfactory sensitization was paralleled by comparable trigeminal processing - in terms of perceptual ratings and BOLD responses. We grouped women from a previous functional magnetic imaging study based on intensity ratings of repeated amyl acetate exposure over time. Fourteen women sensitized to the exposure, 15 habituated, and 20 were considered "intermediate" (i.e. neither sensitizers nor habituaters). Olfactory sensitizers, compared with habituaters, displayed a BOLD-pattern in line with the hypothesis, and reported greater problems with odours in everyday life. They also expressed greater reactions to CO2 in terms of both perceived intensity and BOLD signal. The similarities with pain are discussed.

Extent and orientation of coping in chemical intolerance.

Chemical intolerance is a long-standing illness with minimal guidelines regarding treatment. Hence, individual attempts to cope with the illness gain importance in dealing with its consequences. This study used data from 164 persons with self-reported chemical intolerance to understand the nature of coping with the illness. Coping was studied along two dimensions, the extent and predominant orientation of coping. The association of these coping dimensions with mental health variables of stress, depression, anxiety, burnout, and non-restorative sleep was examined as well. Results revealed that the persons with chemical intolerance used a moderate amount of coping strategies which were slightly more emotion-focused than problem-focused in orientation. Users of both problem-focused and emotion-focused orientations report scores in the normal range on all mental health indices. However, significantly higher level of anxiety was found to be associated with predominantly emotion-focused coping, whereas coping orientation did not differ with respect to the four other mental health indices. The above findings are discussed in relation to existing literature on coping with long-term illness.

Multidimensional assessment of self-reported chemical intolerance and its impact on chemosensory effects during ammonia exposure.

Healthy individuals differ in self-reported chemical intolerance (CI). It is unclear whether this inter-individual variability impacts well-being and performance in environmental and occupational settings with chemical exposures. So far, operational definitions and questionnaires of CI have either emphasized physical symptoms or affective/behavioral disruption. In contrast, this study focused on healthy individuals who reported strong CI which generalized to awareness, physiology, affect, and behavior. We investigated whether generalized self-reported CI is associated with hyper-reactivity and reduced cognitive functioning due to chemosensory-mediated distraction during ammonia exposure. An online sample (N=321) answered established CI questionnaires. Based on the convergent self-reports in these questionnaires, healthy women with generalized CI and healthy female control participants were selected (total N=26). Baseline characterization was performed using implicit association, lung and olfactory function tests, health-related self-reports, plasma inflammatory and metabolic markers. Performance in neurobehavioral tasks, perceptual ratings, nasal inflammatory, neuroendocrine, and autonomic nervous system reactivity were examined by means of a 75-min whole-body challenge to ammonia (stepwise increase: 0-10ppm). Correlational analyses confirmed the multidimensionality of CI. Participants with generalized self-reported CI exhibited better olfactory function and reported stronger pungency during the challenge than controls. Cognitive performance and physiological response to the challenge were comparable between the two groups. Self-reports of CI are complex and not easily assessed by unidimensional questionnaires. While generalized self-reported CI is associated with altered chemosensory processing, it seems unlikely that it modulates health effects and cognitive functioning during chemical exposure.

Risk Factors for Self-Reported Chemical Intolerance: a Two-Year Follow-Up Study

Risk Factors for Self-Reported Chemical Intolerance: a Two-Year Follow-Up Study

Sickness Response Symptoms among Healthy Volunteers after Controlled Exposures to Diesel Exhaust and Psychological Stress

Background: Interactions between acute exposures to environmental chemical contaminants and psychological stress may be important in situations where they are likely to co-occur, ranging in intensity from daily urban living to participation in war. Modification of symptomatic responses by stress may play a role in medically unexplained symptoms attributed to low-level chemical exposures.Objectives: We hypothesized that the combination of exposure to diesel exhaust (DE) and acute psychological stress would cause sickness responses in healthy volunteers. Moreover, these responses would be greater in individuals with self-reported prior chemical odor intolerance.Methods: One hundred adult subjects underwent 1-hr exposures to diluted DE and clean air control. Half of the subjects performed a public-speaking stressor task during the exposures. Subjects completed questionnaires to determine their Chemical Odor Intolerance Index score. Plasma cortisol, end-tidal carbon dioxide, and the severity of 35 symptoms were measured at time points before and after the exposures.Results: Subjects exposed to DE demonstrated small but statistically significant increases in severity for several symptom categories, including sickness response and upper respiratory, central nervous system, and total symptoms. The psychological stressor did not increase symptom severity independently or via interaction with DE. Subjects with prior self-reported chemical intolerance had more severe sickness response symptoms from DE.Conclusions: These results suggest that exposure to DE can cause acute sickness response symptoms and that these symptoms are also associated with increased levels of self-reported chemical intolerance. The results did not confirm our hypothesis that an acute stressor would increase sickness response symptom severity during the exposure.

The association of respiratory problems in a community sample with self-reported chemical intolerance.

This epidemiological study evaluated respiratory histories in those individuals reporting chemical intolerance (CI) in a community population sample. The subsample of 181 completed standard Respiratory Health Questionnaires. CI was determined from self-ratings of feeling 'moderately' to 'severely' ill from exposure to at least three of five common chemicals (paint, pesticides, car exhaust, new carpet, and perfume); the prevalence rate was 22.7%. The comparison group (CN) (31.5% of the sample) were selected from their reports of 'never' feeling ill from the same chemicals. The prevalence rate of CI in females was over twice that in males (28% vs 12.9%), a significant difference. There were no significant differences in smoking, age, or education between CI and CN. Prevalence rates for symptoms and Relative Risk Ratios (RR) indicated that the CI were significantly more likely to report chronic cough, phlegm, wheeze, chest tightness, exertional dyspnea, acute respiratory illnesses, hay fever, child respiratory trouble, and physician confirmed asthma. Several of these respiratory symptoms were significantly, though differentially, related to 'current' asthma and hay fever reports. Results suggest a potential vulnerability to and greater interference from respiratory illness for the CI, which have implications for women's health and quality of life.