Chemical intolerance in primary care settings: prevalence, comorbidity, and outcomes

Multiple Chemical Sensitivity: It's time to catch up to the science

Multiple chemical sensitivity (MCS) is a complex medical condition associated with low dose chemical exposures. MCS is characterized by diverse features and common comorbidities, including fibromyalgia, cough hypersensitivity, asthma, and migraine, and stress/anxiety, with which the syndrome shares numerous neurobiological processes and altered functioning within diverse brain regions. Predictive factors linked to MCS comprise genetic influences, gene-environment interactions, oxidative stress, systemic inflammation, cell dysfunction, and psychosocial influences. The development of MCS may be attributed to the sensitization of transient receptor potential (TRP) receptors, notably TRPV1 and TRPA1. Capsaicin inhalation challenge studies demonstrated that TRPV1 sensitization is manifested in MCS, and functional brain imaging studies revealed that TRPV1 and TRPA1 agonists promote brain-region specific neuronal variations. Unfortunately, MCS has often been inappropriately viewed as stemming exclusively from psychological disturbances, which has fostered patients being stigmatized and ostracized, and often being denied accommodation for their disability. Evidence-based education is essential to provide appropriate support and advocacy. Greater recognition of receptor-mediated biological mechanisms should be incorporated in laws, and regulation of environmental exposures.

Multiple Chemical Sensitivity Syndrome: First Symptoms and Evolution of the Clinical Picture: Case-Control Study/Epidemiological Case-Control Study

Multiple chemical sensitivity (MCS) is a chronic condition characterized by the appearance of symptoms caused by exposure to chemical compounds that are tolerable for the general population. It mainly affects middle-aged women. There are very few studies focusing on the most frequent symptoms of MCS considering age groups and gender. The main goal of this study was to find the most frequent symptoms both at the onset of the disease and at the present time describing them by age groups. The QEESI (Quick Environmental Exposure and Sensitivity Inventory) questionnaire, Scale 3 which assesses symptoms and their severity, was used as a diagnostic tool for the disease. A case-control study was conducted with the participation of 210 people. Of the cases, 94.3% were women. The symptoms that most often manifested first were airway and mucous membrane alterations (68.9%). In the development of the disease, we found cognitive alterations (OR = 31.25), heart or chest problems (OR = 22.49), neuromuscular problems (OR = 20.00) and head-related symptomatology (OR = 19.29). Identifying the most frequent pattern of symptoms by age group and sex will allow an early diagnosis of the disease to improve its prognosis and treatment.

Does improving indoor air quality lessen symptoms associated with chemical intolerance?

Aim:

To determine whether environmental house calls that improved indoor air quality (IAQ) is effective in reducing symptoms of chemical intolerance (CI).

Background:

Prevalence of CI is increasing worldwide. Those affected typically report symptoms such as headaches, fatigue, ‘brain fog’, and gastrointestinal problems – common primary care complaints. Substantial evidence suggests that improving IAQ may be helpful in reducing symptoms associated with CI.

Methods:

Primary care clinic patients were invited to participate in a series of structured environmental house calls (EHCs). To qualify, participants were assessed for CI with the Quick Environmental Exposure and Sensitivity Inventory. Those with CI volunteered to allow the EHC team to visit their homes to collect air samples for volatile organic compounds (VOCs). Initial and post-intervention IAQ sampling was analyzed by an independent lab to determine VOC levels (ng/L). The team discussed indoor air exposures, their health effects, and provided guidance for reducing exposures.

Findings:

Homes where recommendations were followed showed the greatest improvements in IAQ. The improvements were based upon decreased airborne VOCs associated with reduced use of cleaning chemicals, personal care products, and fragrances, and reduction in the index patients’ symptoms. Symptom improvement generally was not reported among those whose homes showed no VOC improvement.

Conclusion:

Improvements in both IAQ and patients’ symptoms occur when families implement an action plan developed and shared with them by a trained EHC team. Indoor air problems simply are not part of most doctors’ differential diagnoses, despite relatively high prevalence rates of CI in primary care clinics. Our three-question screening questionnaire – the BREESI – can help physicians identify which patients should complete the QEESI. After identifying patients with CI, the practitioner can help by counseling them regarding their home exposures to VOCs. The future of clinical medicine could include environmental house calls as standard of practice for susceptible patients.

Multiple Chemical Sensitivity

Multiple Chemical Sensitivity (MCS), a condition also known as Chemical Sensitivity (CS), Chemical Intolerance (CI), Idiopathic Environmental Illness (IEI) and Toxicant Induced Loss of Tolerance (TILT), is an acquired multifactorial syndrome characterized by a recurrent set of debilitating symptoms. The symptoms of this controversial disorder are reported to be induced by environmental chemicals at doses far below those usually harmful to most persons. They involve a large spectrum of organ systems and typically disappear when the environmental chemicals are removed. However, no clear link has emerged among self-reported MCS symptoms and widely accepted objective measures of physiological dysfunction, and no clear dose-response relationship between exposure and symptom reactions has been observed. In addition, the underlying etiology and pathogenic processes of the disorder remain unknown and disputed, although biologic and psychologic hypotheses abound. It is currently debated whether MCS should be considered a clinical entity at all. Nevertheless, in the last few decades MCS has received considerable scientific and governmental attention in light of the many persons reporting this illness. In this review, we provide a general overview of the history, definition, demographics, prevalence, and etiologic challenges in defining and understanding MCS.

The effects of smoking, regular drinking, and unhealthy weight on health care utilization in China

Background

Preventive risk factors such as smoking, drinking, and unhealthy weight have contributed to the accelerated rise in noncommunicable chronic diseases, which are dominant drivers of health care utilization and spending in China. However, few studies have been conducted using a large longitudinal dataset to explore the impact of such preventive risk factors on health care utilization. Therefore, this study aimed to ascertain the effects of smoking, regular drinking, and unhealthy weight on health care utilization in China.

Methods

This research was a longitudinal study using data from five waves of the China Family Panel Studies (CFPS) conducted between 2010 and 2018, and the final sample consisted of 63,260 observations (12,652 participants) across all five waves of data collection. Health care utilization was measured from two perspectives: outpatient utilization and inpatient utilization. Smoking status was categorized as never smoker, former smoker, or current smoker. Unhealthy weight was classified based on the participants’ body mass index. A fixed effects logistic regression model was used for the analysis.

Results

The results of fixed effects logistic regression showed that current and former smokers were approximately 1.9 times and 2.0 times more likely to use outpatient care than those who never smoked, respectively (odds ratio (OR) = 1.88, p < 0.05; OR = 2.03, p < 0.05). Obese people were approximately 1.3 times more likely to use outpatient care than healthy weight people (OR = 1.26, p < 0.05). Moreover, the results show that compared to those who never smoked, for current and former smokers, the odds of being hospitalized increased by 42.2 and 198.2%, respectively (OR = 1.42; p < 0.1, OR = 2.98; p < 0.05). Compared to healthy weight people, overweight and obese people were also more likely to be hospitalized (OR = 1.11; p < 0.1, OR = 1.18; p < 0.1, respectively).

Conclusion

Among Chinese adults, current and former smokers were more likely to use outpatient and inpatient care than those who had never smoked. Moreover, compared to healthy weight people, obese people were more likely to use outpatient and inpatient care, and overweight people were more likely to use inpatient care. These results may have important implications that support the government in making health care resource allocation decisions.

Multiple Chemical Sensitivity in Patients Exposed to Moisture Damage at Work and in General Working-Age Population-The SAMDAW Study

A considerable proportion of patients having respiratory tract or voice symptoms associated with workplace moisture damage (MD) could have multiple chemical sensitivity (MCS). MCS is characterized by symptoms of different organ systems in association with low-level chemical exposure. The objective of this study was to assess the prevalence of MCS among patients referred to secondary health care because of respiratory or voice symptoms associated with workplace MD compared to the general working-age population. Using three subscales of the QEESI© questionnaire, we assessed MCS in the study patients and 1500 controls in the same district randomly selected from the Finnish Population Information System. Study patients had significantly more often high scores in chemical intolerance (39% vs. 23%, p = 0.001), symptom severity (60% vs. 27%, p < 0.001), and life impact subscales (53% vs. 20%, p < 0.001). Asthma, chronic rhinosinusitis, laryngeal problems, and atopy were not associated with the presence of MCS. MCS is common among patients referred to secondary health care with respiratory tract and/or voice symptoms associated with workplace MD, and it considerably affects their everyday life. MCS should be considered as a possible explanatory factor for MD-associated symptoms.

Validation of a Brief Screening Instrument for Chemical Intolerance in a Large U.S. National Sample

Background: Chemical intolerance (CI) is characterized by multisystem symptoms triggered by low levels of exposure to xenobiotics including chemicals, foods/food additives, and drugs/medications. Prior prevalence estimates vary from 8–33% worldwide. Clinicians and researchers need a brief, practical screening tool for identifying possible chemical intolerance. This large, population-based study describes the validation of a three-item screening questionnaire, the Brief Environmental Exposure and Sensitivity Inventory (BREESI), against the international reference standard used for assessing chemical intolerance, the Quick Environmental Exposure and Sensitivity Inventory (QEESI). Methods: More than 10,000 people in the U.S. responded to the BREESI and the QEESI in a population-based survey. We calculated the overall prevalence of CI in this sample, as well as by gender, age, and income. Common statistical metrics were used to evaluate the BREESI as a screener for CI against the QEESI. Results: The prevalence estimate for QEESI-defined chemical intolerance in the U.S. was 20.39% (95% CI 19.63–21.15%). The BREESI had 91.26% sensitivity (95% CI: 89.20–93.04%) and 92.89% specificity (95% CI: 91.77–93.90%). The positive likelihood ratio was 12.83 (95% CI: 11.07–14.88), and the negative likelihood ratio was 0.09 (95% CI: 0.08–0.12). Logistic regression demonstrates that the predicted probability of CI increased sharply with each increase in the number of BREESI items endorsed (Odds Ratio: 5.3, 95% CI: 4.90–5.75). Conclusions: Chemical intolerance may affect one in five people in the U.S. The BREESI is a new, practical instrument for researchers, clinicians, and epidemiologists. As a screening tool, the BREESI offers a high degree of confidence in case ascertainment. We recommend: screen with the BREESI, confirm with the QEESI.

Patients With Somatoform Disorders Are Prone To Expensive and Potentially Harmful Medical Procedures

BACKGROUND

Patients with functional somatic syndromes (FSS) might be prone to potentially harmful medical investigations in ambulatory care. The primary aim was to investigate whether patients with FSS are more likely to undergo diagnostic examinations such as radiography, computed tomography (CT), magnetic reso - nance imaging (MRI), and outpatient surgical procedures. The secondary aim was to evaluate the extent to which coordination of care by primary care physicians reduces healthcare utilization.

METHODS

Retrospective cohort study using longitudinal regression analysis of routine data. FSS patients were weighted in the regression model to allow a representative comparison with the Bavarian population. The observation period was from 5 years before until 10 years after the diagnosis of FSS.

RESULTS

The cohort comprised 43 676 patients with FSS and a control group of 50 003 patients without a diagnosis of FSS. The FSS patients exhibited continuously increased healthcare utilization over the 15-year period. The relative risk (RR) for FSS patients was up to 1.48 (95% confidence interval [1.46; 1.50]) for radiography, 2.01 [1.94; 2.08] for CT, 1.91 [1.87; 1.96] for MRI, and 1.30 [1.27; 1.34] for outpatient surgery. Compared with patients whose treatment was coordinated by their primary care physician, patients with no such coordination showed higher service utilization. The ambulatory care costs were up to 1.37 [1.36; 1.38] times greater.

CONCLUSION

Patients with FSS more frequently undergo potentially harmful and costly diagnostic testing and outpatient surgery. Coordination of care by the primary care physician is associated with lower healthcare utilization.

PON1 polymorphisms can predict generalized anxiety and depressed mood in patients with multiple chemical sensitivity

Background: Multiple chemical sensitivity (MCS) is a chronic condition with somatic, cognitive and affective symptoms that follow contact with chemical agents at usually non toxic concentrations. We aimed to assess the role of genetic polymorphisms involved in oxidative stress on anxiety and depression in MCS. Materials & methods: Our study investigated the CAT rs1001179, MPO rs2333227, PON1 rs662 and PON1 rs705379 polymorphisms in MCS. Results: The AG genotype of the PON1 rs662 and the TT and CT genotypes of the PON1 rs705379 were involved in anxiety and depression. Discussion: These results are in line with existing evidence of PON1 involvement in MCS and suggest a further role of this gene in the exhibition of anxiety and depression in this disease.

Three questions for identifying chemically intolerant individuals in clinical and epidemiological populations: The Brief Environmental Exposure and Sensitivity Inventory (BREESI)

The Quick Environmental Exposure and Sensitivity Inventory (QEESI) is a validated questionnaire used worldwide to assess intolerances to chemicals, foods, and drugs, and has emerged as the gold standard for assessing chemical intolerance (CI). Despite a reported prevalence of 8–33%, epidemiological studies and routine primary care clinics rarely assess CI. To help address this gap, we developed the Brief Environmental Exposure and Sensitivity Inventory (BREESI)—a 3-item CI screening tool. We tested the BREESI’s potential to predict whether an individual is likely to be classified as chemically intolerant if administered the 50-item QEESI. We recruited 293 participants from a university-based primary care clinic and through online participation. The statistical sensitivity, specificity, and positive and negative predictive values of the BREESI were calculated against the validated QEESI. Ninety percent (90%) of participants answering “yes” to all three items on the BREESI fit the QEESI criteria for being very suggestive of CI based upon their chemical intolerance and symptom scores (positive predictive value = 90%). For participants endorsing two items, 93% were classified as either very suggestive (39%) or suggestive (54%) of CI (positive predictive value = 87%). Of those endorsing only one item, 13% were classified as very suggestive of CI, and 70% as suggestive. Of those answering “No” to all of the BREESI items, 95% were classified as not suggestive of CI (i.e., negative predictive value = 95%). The BREESI is a versatile screening tool for assessing potential CI useful for clinical and epidemiological applications, based upon individuals’ past adverse responses in a variety of settings. Just as health care professionals routinely inquire about latex allergy to prevent adverse reactions, the BREESI provides an essential screen for CI. Together, the BREESI and QEESI provide new diagnostic tools that may help predict and prevent future adverse reactions to chemicals, foods, and drugs.

Multiple Chemical Sensitivity Syndrome: A Principal Component Analysis of Symptoms

Multiple Chemical Sensitivity (MCS) is a chronic and/or recurrent condition with somatic, cognitive, and affective symptoms following a contact with chemical agents whose concentrations do not correlate with toxicity in the general population. Its prevalence is not well defined; it mainly affects women between 40 and 50 years, without variations in ethnicity, education and economic status. We aimed to assess the core symptoms of this illness in a sample of Italian patients. Two physicians investigated different symptoms with a checklist compilation in 129 patients with MCS (117 women). We conducted a categorical Principal Component Analysis (CATPCA) with Varimax rotation on the checklist dataset. A typical triad was documented: hyperosmia, asthenia, and dyspnoea were the most common symptoms. Patients also frequently showed cough and headache. The CATPCA showed seven main factors: 1, neurocognitive symptoms; 2, physical (objective) symptoms; 3, gastrointestinal symptoms; 4, dermatological symptoms; 5, anxiety-depressive symptoms; 6, respiratory symptoms; 7, hyperosmia and asthenia. Patients showed higher mean prevalence of factors 7 (89.9%), 6 (71.7%), and 1 (62.13%). In conclusion, MCS patients frequently manifest hyperosmia, asthenia, and dyspnoea, which are often concomitant with other respiratory and neurocognitive symptoms. Considering the clinical association that is often made with anxiety, more studies are necessary on the psychosomatic aspects of this syndrome. Further analytical epidemiological studies are needed to support the formulation of aetiological hypotheses of MCS.

Study of the Correlation Between Multiple Chemical Sensitivity and Personality Using the Quick Environmental Exposure Sensitivity Inventory Questionnaire and the Temperament and Character Inventory

OBJECTIVE

We conducted an analysis using the Quick Environmental Exposure Sensitivity Inventory to examine the correlation between multiple chemical sensitivity (MCS) and personality traits by using temperament and character inventory, and environmental exposures.

METHODS

An anonymous questionnaire was distributed to 667 employees working at an IT manufacturing plant in Japan. Variables including chemically sensitive population (CSP), personality, and environmental chemical exposure were individually evaluated using U-test, chi-squared test, and correlation analyses. We also did covariance structure analysis to build a structural equation model.

RESULTS

There was little direct impact of temperament on the CSP, while there was a significant impact of character on the CSP. Women were more likely to exhibit symptoms of CSP.

CONCLUSION

MCS is correlated with personality, impacted more by character acquired later in life than innate temperament. There were sex differences in the incidence of MCS.

The impact of multiple chemical sensitivity on people's social and occupational functioning; a systematic review of qualitative research studies

OBJECTIVE

Social and occupational functioning are important for psychological health. However, quantitative research has suggested that these areas can be adversely affected by multiple chemical sensitivity (MCS). This systematic review therefore sought to explore what qualitative research has suggested about how people with MCS perceive it to affect their social and occupational functioning.

METHOD

Journal articles were included if they were 1) peer reviewed 2) qualitative or mixed methods 3) published in English 4) reported qualitative findings relevant to the review. Studies were excluded if they were 1) descriptive only 2) primarily concerned with environmental intolerances other than chemicals or 3) focussed on specific populations such as veterans. Quality was assessed using the National Institute for Health and Care Excellence (NICE, 2018) qualitative quality criteria. However, quality was not used to determine eligibility for inclusion. Six databases (CINAHL, Medline, PsychArticles, PsychInfo, Scopus and Web of Science) were searched between the 24th of February 2019 and 2nd of March 2019.

RESULTS

Having removed duplicates, database searches identified 388 potential articles. Thirteen of these articles were eligible for inclusion. Following review, no more articles were included from the reference lists of these studies. Meta-aggregation of the findings identified seven categories. These were synthesised into three themes; 'limited access', 'loss & anxiety' and 'seeking engagement'.

CONCLUSIONS

The findings suggested that MCS limits some people's social and occupational functioning. The results warrant further research, and, the development of prevention and intervention strategies. Studies predominantly recruited United States and Canadian females and had several limitations.

Multiple Chemical Sensitivity: Review of the State of the Art in Epidemiology, Diagnosis, and Future Perspectives

OBJECTIVE

Systematic bibliography analysis of about the last 17 years on multiple chemical sensitivity (MCS) was carried out in order to detect new diagnostic and epidemiological evidence. The MCS is a complex syndrome that manifests as a result of exposure to a low level of various common contaminants. The etiology, diagnosis, and treatment are still debated among researchers.

METHOD

Querying PubMed, Web of Science, Scopus, Cochrane library, both using some specific MESH terms combined with MESH subheadings and through free search, even by Google.

RESULTS

The studies were analyzed by verifying 1) the typology of study design; 2) criteria for case definition; 3) presence of attendances in the emergency departments and hospital admissions, and 4) analysis of the risk factors.

OUTLOOK

With this review, we give some general considerations and hypothesis for possible future research.

Health-related quality among life of employees with persistent nonspecific indoor-air-associated health complaints

OBJECTIVE

Nonspecific health complaints associated with indoor air are common in work environments. In some individuals, symptoms become persistent without an adequate explanation. The aim was to study factors that associate with the health-related quality of life (HRQoL) of employees with persistent, nonspecific indoor-air-related symptomatology.

METHODS

We present baseline results of a randomized controlled trial of interventions targeted on the HRQoL of the employees with indoor-air-associated nonspecific symptoms. The main participant-inclusion criterion was the presence of persistent indoor-air-related multiorgan symptoms with no known pathophysiological or environment-related explanation. As a comparison for participants´ HRQoL (n = 52) we used data from the general-population Health 2011 study (BRIF8901) including information on subjects matched to the participants´ working status and age and subjects with asthma, anxiety or depressive disorder, or other chronic conditions with work disability.

RESULTS

The participants showed greater and a clinically significant impairment of HRQoL [M = 0.83, SE = 0.013] than individuals from the general population [M = 0.95, SE = 0.001, p < .001, Hedges´ g = 2.33] and those with asthma [M = 0.93, SE = 0.005, p < .001, Hedges´ g = 1.46], anxiety and depressive disorder [M = 0.89, SE = 0.006, p < .001, Hedges´ g = 0.73], or a chronic condition with work disability [M = 0.91, SE = 0.003, p < .001, Hedges´ g = 1.11]. Prevalent symptoms of depression, anxiety, and insomnia and poor recovery from work were associated with a poor HRQoL.

CONCLUSIONS

Individuals with nonspecific indoor-air-associated symptoms have a poorer HRQoL than individuals in the general population with a globally burdensome disease. Psychological distress associated with a poor HRQoL should be considered in the making of decisions about the treatment of these patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02069002.

Clinical Characteristics of Disability in Patients with Indoor Air-Related Environmental Intolerance

Background

Chronic nonspecific symptoms attributed to indoor nonindustrial work environments are common and may cause disability, but the medical nature of this disability is unclear. The aim was to medically characterize the disability manifested by chronic, recurrent symptoms and restrictions to work participation attributed to low-level indoor pollutants at workplace and whether the condition shares features with idiopathic environmental intolerance.

Methods

We investigated 12 patients with indoor air–related work disability. The examinations included somatic, psychological, and psychiatric evaluations as well as investigations of the autonomic nervous system, cortisol measurements, lung function, and allergy tests. We evaluated well-being, health, disability, insomnia, pain, anxiety, depression, and burnout via questionnaires.

Results

The mean symptom history was 10.5 years; for disabling symptoms, 2.7 years. Eleven patients reported reactions triggered mainly by indoor molds, one by fragrances only. Ten reported sensitivity to odorous chemicals, and three, electric devices. Nearly all had co-occurrent somatic and psychiatric diagnoses and signs of pain, insomnia, burnout, and/or elevated sympathetic responses. Avoiding certain environments had led to restrictions in several life areas. On self-assessment scales, disability showed higher severity and anxiety showed lower severity than in physician assessments.

Conclusion

No medical cause was found to explain the disability. Findings support that the condition is a form of idiopathic environmental intolerance and belongs to functional somatic syndromes. Instead of endless avoidance, rehabilitation approaches of functional somatic syndromes are applicable.

Prognostic value of hypersensitivity reactions on epidural steroid injection outcomes: a phenotypic signature? A prospective cohort study

Background

Studies have found that diffuse pain, indicative of central sensitization, portends poor interventional outcomes. Multiple chemical sensitivities are associated with signs of central sensitization. We sought to prospectively determine whether hypersensitivity reactions (HR) were associated with epidural steroid injection (ESI) outcomes.

Methods

HR were classified as immune-related or non-immune-related and categorized by number (0=low, 1 or 2=intermediate, ≥3=high). The primary outcome measure was mean reduction in average leg pain score 1 month post-procedure. A positive outcome was defined as a two-point or greater decrease in average leg pain accompanied by satisfaction 1 month post-procedure.

Results

The mean number of immune-mediated and non-immune-mediated HR were 0.6±1.2 and 0.8±1.4, respectively. Individuals in the high (n=24) total HR group had a mean reduction in average leg pain of 0.1±2.7, compared with those in the low (n=61; 1.8±2.1, p=0.025) and intermediate groups (n=52; 1.6±3.1, p=0.060). For back pain and categorical successful outcome, those with fewer HR experienced greater benefit. There were no differences in outcomes when patients were stratified by immune-related HR. Among participants in the low, intermediate and high non-immune-mediated HR groups, the mean reductions in average leg pain scores were 1.7±2.5, 1.6±3.0, and −0.2±2.3, respectively (p = 0.002). 51%, 35%, and 12% of people with low, intermediate and high numbers of non-immune-mediated HR experienced a positive categorical outcome, respectively (p=0.007).

Conclusions

Non-immune-related HR were inversely correlated with some ESI outcome measures.

Assessment of CYP2C9, CYP2C19, and CYP2D6 Polymorphisms in Allergic Patients with Chemical Sensitivity

BACKGROUND

Self-reported chemical sensitivity (SCS) is characterized by adverse effects due to exposure to low levels of chemical substances. The clinical manifestations of SCS are similar to the allergy, and a high percentage of individuals with both diseases have been found. Various genes, especially genes of importance to the metabolism of xenobiotic compounds, have been associated with SCS.

OBJECTIVES

The purpose of this study was to investigate whether allergic individuals with chemical sensitivity differed from allergic patients without chemical sensitivity with regard to the distribution of genotype and phenotype of CYP2C9, CYP2C19, and CYP2D6 polymorphisms.

METHODS

A total of 180 patients were enrolled for this study. A questionnaire was employed to collect information on individual chemical sensitivity, while the Skin prick test and the PATCH test were used to verify the presence of an allergic condition against inhalants or contact allergens, respectively. For the evaluation of the CYP2C9, CYP2C19, and CYP2D6 polymorphisms, we used a strategy based on the amplification of the entire gene coupled to direct genomic DNA sequencing analysis.

RESULTS

Overall, a total of 15 different CYP2C9, CYP2C19, and CYP2D6 haplotypes were identified in our population. If the 5 CYP2C9 and the 2 CYP2C19 identified alleles correspond to the previously described ones, 4 of the 8 CYP2D6 haplotypes, detected in the study group, present new SNPs combinations. These new suballeles were categorized as CYP2D6*2M Sa-lento Variant 1, CYP2D6*35B Salento Variant 2, CYP2D6*41 Salento Variant 3, and CYP2D6*4P Salento Variant 4 due to the presence of the key SNPs 2,850 C>T, 31G>A, 2,988 G>A, and 1,846 G>A, respectively. When the allergic individuals are divided into 2 groups according to their SCS score, we observed that the distribution of the CYP2D6 phenotypes was significantly different between the 2 groups.

CONCLUSIONS

Our idea is that the application of the questionnaire that we have adopted has enabled us to diagnose a degree of chemical sensitivity, which results as comorbid of the allergic disease and in which a condition of poor or intermediate metabolizes for the detrimental CYP2D6 alleles, could represent a discriminant between the chemical sensitivity and the health state.

Fibromyalgia, Chronic Fatigue Syndrome, and Multiple Chemical Sensitivity: Illness Experiences

Fibromyalgia, chronic fatigue syndrome/myalgic encephalomyelitis, and multiple chemical sensitivity can be considered contested illnesses. The questioning of the status of these conditions as real diseases reduces feelings of legitimacy in those affected. The purpose of this study was to analyze subjectivity construction processes in people with these diseases. A qualitative exploratory study was conducted from the perspective of hermeneutic phenomenology and ethnosociology. We used life stories for compiling data (13 informants were interviewed face-to-face), and sociological discourse analysis was developed. Three main categories were identified: (a) self and grieving; (b) images and practices relating to fibromyalgia, chronic fatigue syndrome/myalgic encephalomyelitis, and multiple chemical sensitivity; and (c) relationships with health professionals. This study shows that daily experiences of people living with these diseases are marked by stigmatization processes. The ultimate purpose of nursing care for people with these conditions should be to reduce their vulnerability and exclusion.

Environmental Intolerance, Symptoms and Disability Among Fertile-Aged Women

The purpose was to study the prevalence of environmental intolerance (EI) and its different manifestations, including behavioral changes and disability. Fertile-aged women (n = 680) of the Kuopio Birth Cohort Study were asked about annoyance to 12 environmental factors, symptoms and behavioral changes. We asked how much the intolerance had disrupted their work, household responsibilities or social life. We chose intolerance attributed to chemicals, indoor molds, and electromagnetic fields to represent typical intolerance entities. Of the respondents, 46% reported annoyance to chemicals, molds, or electromagnetic fields. Thirty-three percent reported symptoms relating to at least one of these three EIs, 18% reported symptoms that included central nervous system symptoms, and 15% reported behavioral changes. Indicating disability, 8.4% reported their experience relating to any of the three EIs as at least “somewhat difficult”, 2.2% “very difficult” or “extremely difficult”, and 0.9% “extremely difficult”. Of the latter 2.2%, all attributed their intolerance to indoor molds, and two thirds also to chemicals. As the number of difficulties increased, the number of organ systems, behavioral changes and overlaps of the three EIs also grew. EI is a heterogeneous phenomenon and its prevalence depends on its definition. The manifestations of EI form a continuum, ranging from annoyance to severe disability.

Preliminary evidence for differential olfactory and trigeminal processing in combat veterans with and without PTSD

Structural and functional changes in the olfactory system are increasingly implicated in the expression of PTSD. Still, very little is known about the neurobiological networks of trauma-related odor sensitivity or how they relate to other objective and subjective measures of olfaction and PTSD. The purpose of this study was to replicate prior findings and further characterize olfactory function in trauma-exposed combat veterans with and without PTSD. We also sought to extend this area of research by exploring the effects of time since the combat-related index trauma (TST) on post-trauma olfactory function, as well as by correlating odor-elicited brain activity to general olfactory ability and odor-elicited PTSD symptoms. Participants included combat veterans with PTSD (CV+PTSD; n = 21) or without any psychiatric disorder (CV-PTSD; n = 27). TST was coded as greater (n = 24) or less (n = 24) than 5 years. There were main effects and/or interaction for PTSD-status and TST across several parameters of olfactory function: odor detection, odor identification, ratings for trauma-related odor intensity and triggered PTSD symptoms, and trauma odor-elicited brain activation. Overall, results suggest olfactory impairment in chronic PTSD, but not necessarily in the earlier stages of the disorder, although some early-stage olfactory findings may be predictive of later olfactory impairment. Results also suggest that trauma-exposed individuals who never develop PTSD may demonstrate olfactory resiliency. Finally, results highlight a potentially unique role of trigeminal odor properties in the olfactory-PTSD relationship.

The association between multiple chemical sensitivity and mental illness: Evidence from a nationally representative sample of Canadians

OBJECTIVE

The goal of the present study was to investigate the association between multiple chemical sensitivity (MCS) and major depressive disorder (MDD), generalized anxiety disorder (GAD), MDD and GAD comorbidity (MDD+GAD), severe distress, and positive mental wellbeing.

METHODS

This cross-sectional investigation was carried out using the 2012 Canadian Community Health Survey - Mental Health Component. The study population consisted of 21,977 individuals aged 20 and older, from Canada's ten provinces. Odds ratios were computed using multinomial logistic regression to calculate estimates of the association between MCS and mental illness. All analyses were weighted to take into account the complex survey design.

RESULTS

Individuals with MCS had 2.37 (1.55, 3.64) times greater odds of MDD, 3.09 (1.80, 5.30) times greater odds of MDD+GAD, and 2.60 (1.67, 4.07) times greater odds of severe distress. No association between MCS and GAD was observed. A sex difference was observed with males with MCS having lower odds of positive mental wellbeing, whereas no association was observed in females.

CONCLUSIONS

The present study findings supported an association between MCS and mental illness. The causal mechanism supporting this association remains unclear.

Differences in psychological and somatic symptom cluster score profiles between subjects with Idiopathic environmental intolerance, major depression and schizophrenia

Idiopathic Environmental Intolerance (IEI) has been associated with psychogenic factors and an increased number of comorbid psychiatric disorders such as depression and anxiety disorder. The purpose of the current study was to examine a possible overlap of psychological and somatic symptoms between subjects with IEI and patients with major depression and schizophrenia as well as to specify characteristic differences. The different symptom clusters included symptoms of chemical intolerance, neurotoxicity and psychological distress as well as measurements of mental health such as anxiety, depression, somatoform symptoms, and schizophrenia-specific disturbances in cognitive domains. IEI patients reported higher overall levels in physical symptoms such as chemical intolerance, neurotoxicity and somatic symptoms not attributable to an organic cause. Schizophrenia patients showed higher overall levels in self-experienced disturbances in several schizophrenia-specific cognitive domains, whereas general psychological distress, anxiety and depression were rated highest by patients with major depression. Importantly, the groups markedly differed in the shapes of profiles of various symptom clusters. Our results provide evidence that IEI patients can be distinguished on the phenomenological level from patients with major depression or schizophrenia, and that distinct domains of psychological and somatic symptoms are particularly problematic in specific diagnostic groups.

Long-Term Follow-Up in Patients With Airway Chemical Intolerance

OBJECTIVE

A 5-year follow-up study showed that a group of patients with airway symptoms from chemicals and scents had lasting symptoms, together with enduring increased capsaicin cough sensitivity. The aim was to follow up the same patients after another 5 years.

METHODS

All previously participants were invited for an additional follow-up. They visited the clinic twice; at one opportunity, they undertook a capsaicin inhalation provocation, and at the other, a methacholine provocation, and answered various questionnaires.

RESULTS

Sixteen patients attende the study after a median of 8 years. They reported unchanged symptoms from chemicals and scents; the capsaicin cough sensitivity was still increased, and the repeatability for the capsaicin inhalation was good.

CONCLUSIONS

Airway symptoms induced by chemicals and scents constitute a chronic disease, with unchanged trigger factors, persistent symptoms, and unchanged, long-lasting sensory hyperreactivity.All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.This study was supported by grants from the Herman Krefting Foundation Against Asthma/Allergy, the Swedish Heart and Lung Foundation, and the Swedish Cancer and Allergy Fund.

Experiences of persons with multiple chemical sensitivity with mental health providers

In this paper, we summarize the results of an online survey of persons in the United States with chemical intolerance/multiple chemical sensitivity who sought help from mental health providers, including counselors, psychologists, psychiatrists, and others. Respondents reported on their most recent contact with a provider, describing reasons for the contact, accommodations requested and received, and suggestions for how the experience could be more helpful. Overall, though clients were accommodated in small ways, some received no accommodation, and many felt that the providers needed to be more knowledgeable regarding chemical intolerance. Results are discussed in terms of the importance of providers becoming more aware of multiple chemical sensitivity and more willing to make their services accessible to these clients.

Nickel sensitization in patients with gastro-esophageal reflux disease

BACKGROUND

Gastro-esophageal reflux disease (GERD) leads to frequent medical visits, and available therapies fail in up to 40% of patients. Food allergies may be involved in GERD pathogenesis; however, allergens other than food have received little attention. Nickel allergy is common in the general population and some high-nickel foods are associated with GERD. However, the potential relationship between nickel allergy and GERD remains unaddressed.

AIM

This study aimed to evaluate the prevalence of nickel sensitization in patients with and without GERD and to compare clinical and demographic features.

METHODS

This prospective, multicenter study included 210 adult GERD patients and 140 patients without GERD who presented at the general practitioner. All GERD patients had undergone treatment with proton pump inhibitors and upper digestive endoscopy within the previous five years. Demographic and clinical data were collected by questionnaire and patients underwent a nickel patch allergy test.

RESULTS

Patients with and without GERD presented similar characteristics, with the exception of nickel sensitization, which was significantly more prevalent among GERD patients than controls (39.5% vs. 16.4%; p = 0.001). Nickel-positive GERD patients were more frequently female (90.4% vs. 65.4%, p = 0.003) and asthmatic (18.1% vs. 4.7%; p = 0.038), compared to nickel-negative GERD patients. At six-month follow-up, most of the patients, with or without nickel sensitization, reported improved symptoms without differences in drug prescription.

CONCLUSION

Nickel sensitization is particularly prevalent in GERD patients seen in general practice. Whether allergies other than food allergy play a role in GERD remains to be elucidated.

The correlation between mental health and multiple chemical sensitivity: a survey study in Japanese workers

OBJECTIVE

This study was designed to determine the correlation between mental health and multiple chemical sensitivity (MCS).

METHOD

The present study was conducted at two companies in 2011; both in Kyushu, Japan. The "subjective symptoms" subscale of the "Self-diagnosis Checklist for Assessment of Workers' Accumulated Fatigue" was used as a mental health subscale. To determine if multiple chemical exposure has an impact on mental health, we composed an original path model using structural equation analysis.

RESULT

Our final path model can be regarded as good: CMIN/DF = 1.832, CFI = 0.996, and RMSEA = 0.038, AIC = 71.158. As expected, chemical sensitivity and other chemical sensitivity scores predicted the health effects of multiple chemical exposure (β = 0.19, 0.64). Mental health was predicted by symptom severity and life impact (β = 0.56 and 0.12), which were both affected by multiple chemical exposure (β = 0.38 and 0.89, respectively).

CONCLUSION

As far as we are aware, this is the first study using path analysis to explore whether MCS can indicate mental health in worker populations worldwide, and we found a significant causal relationship between them. This could indicate that more focus should be placed on the impact of MCS on mental health in future investigations.

Approach to patients with unexplained multimorbidity with sensitivities

OBJECTIVE

To explore the underlying causation of unexplained multimorbidity with sensitivities and to discuss the management of patients who present with this perplexing condition.

SOURCES OF INFORMATION

Medical and scientific literature was used from MEDLINE (PubMed), several books, toxicology and allergy journals, conference proceedings, government publications, and environmental health periodicals.

MAIN MESSAGE

Multimorbidity with sensitivities has become an increasingly common and confusing primary care dilemma. Escalating numbers of debilitated individuals are now presenting to family physicians and specialists with multisystem health complaints, including sensitivities and fatigue, with no obvious causation, a paucity of laboratory findings, and a lack of straightforward solutions. In the recent scientific literature, there is discussion of sensitivity-related illness, an immune-mediated disorder that frequently manifests with multisystem symptoms, commonly including sensitivities and fatigue. This condition appears to be originally caused by adverse environmental exposures and toxicant bioaccumulation-an increasingly prevalent and well-documented problem in contemporary culture.

CONCLUSION

Various toxic exposures and their bioaccumulation within the body frequently manifest as sensitivity-related illness. In clinical settings, patients with this disorder often present with otherwise unexplained multimorbidity and sensitivities. The health status of patients with this condition can be ameliorated by removing triggers (eg, scented products), optimizing biochemistry, removing further sources of toxicant exposures, and eliminating the internal dose of persistent toxicants.

Comparing non-specific physical symptoms in environmentally sensitive patients: prevalence, duration, functional status and illness behavior

OBJECTIVE

Little is known about the potential clinical relevance of non-specific physical symptoms (NSPS) reported by patients with self-reported environmental sensitivities. This study aimed to assess NSPS in people with general environmental sensitivity (GES) and idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) and to determine differences in functional status and illness behavior.

METHODS

An epidemiological study was conducted in the Netherlands, combining self-administered questionnaires with the electronic medical records of the respondents as registered by general practitioners. Analyses included n=5789 registered adult (≥18 years) patients, comprising 5073 non-sensitive (NS) individuals, 514 in the GES group and 202 in the IEI-EMF group.

RESULTS

Participants with GES were about twice as likely to consult alternative therapy compared to non-sensitive individuals; those with IEI-EMF were more than three times as likely. Moreover, there was a higher prevalence of symptoms and medication prescriptions and longer symptom duration among people with sensitivities. Increasing number and duration of self-reported NSPS were associated with functional impairment, illness behavior, negative symptom perceptions and prevalence of GP-registered NSPS in the examined groups.

CONCLUSION

Even after adjustment for medical and psychiatric morbidity, environmentally sensitive individuals experience poorer health, increased illness behavior and more severe NSPS. The number and duration of self-reported NSPS are important components of symptom severity and are associated with characteristics similar to those of NSPS in primary care. The substantial overlap between the sensitive groups strengthens the notion that different types of sensitivities might be part of one, broader environmental illness.

Multiple chemical sensitivity worsens quality of life and cognitive and sensorial features of sense of smell

Multiple chemical sensitivity (MCS) is characterized by a loss of tolerance to a variety of environmental chemicals. Multiple chemical sensitivity is frequently triggered by exposure to chemical agents, especially insecticides. The aim of the study was to measure the sense of smell and quality of life in patients with MCS compared to the control group. We studied the sense of smell, both sensitive and sensorial characteristics, in female patients with MCS (n = 58, mean 50.5 ± 8.5 years) and healthy female volunteers without rhinosinusal pathologies (n = 60, mean age 46 ± 10.2 years). Olfactometry (Barcelona Smell Test 24/BAST-24), sinonasal symptoms (visual analogue scale/VAS 0-100 mm), and quality of life (Quick Environmental Exposure and Sensitivity Inventory/QEESI) were assessed. Multiple chemical sensitivity patients showed a significant impairment in smell identification (19 ± 12 %; p > 0.05) and forced choice (62 ± 18 %; p > 0.05), but not in smell detection (96 ± 4 %) compared to the control group. Multiple chemical sensitivity patients reported more odours as being intense and irritating and less fresh and pleasant when compared with the control group. Patients scored a high level (40-100) on QEESI questionnaire (symptom severity, chemical intolerances, other intolerances, life impact). In MCS patients, total symptom intensity (VAS/0-700 mm) score was 202 ± 135, while disease severity score was 80 ± 23. The most frequent symptoms were itching and posterior rhinorrhea. Multiple chemical sensitivity patients have an impairment in smell cognitive abilities (odour identification and forced choice, but not for detection) with increased smell hypersensitivity and poor quality of life.

Allergic diseases and multiple chemical sensitivity in korean adults

Purpose

Multiple chemical sensitivity (MCS) is a clinical syndrome representing multi-organ and psychological symptoms caused by chronic exposure to various chemicals in low concentrations. We evaluated the prevalence and related factors of MCS targeting Korean adults using the Quick Environmental Exposure and Sensitivity Inventory (QEESI©).

Methods

A total of 446 participants were recruited from Severance Hospital. Participants underwent a questionnaire interview including questions on sociodemographic factors, occupational and environmental factors, allergic diseases, and the QEESI©. Among them, 379 participants completed the questionnaire and the QEESI©. According to the QEESI© interpretation results, participants were divided into very suggestive (VS) group and less suggestive (LS) group.

Results

The estimated prevalence of MCS was higher in allergic patients than non-allergic participants (19.7% and 11.3%, respectively, P=0.04). In the multivariate logistic regression analysis, ages of 30-39 (OR, 2.94; 95% CI, 1.25-6.95) and those of 40-49 (OR, 2.51; 95% CI, 1.02-6.21) were significantly related to MCS compared to those aged less than 30 years. Female sex (OR, 2.16; 95% CI, 1.11-4.18), experience of dwelling in a new house (OR, 2.05; 95% CI, 1.04-4.03), and atopic dermatitis (OR, 1.95; 95% CI, 1.04-3.69) were also significantly related to MCS. However, only age of 30-39 in the allergic group was significant in the stratified analysis.

Conclusions

The estimated prevalence of MCS was higher among allergic patients than non-allergic participants. People with experience of dwelling in a new house and atopic dermatitis were more at risk of being intolerant to chemicals. Further studies to provide the nationally representative prevalence data and clarify risk factors and mechanisms of MCS are required.

Multiple chemical sensitivity and the workplace: current position and need for an occupational health surveillance protocol

Multiple chemical sensitivity, commonly known as environmental illness, is a chronic disease in which exposure to low levels of chemicals causes correlated symptoms of varying intensity. With the continuous introduction of new substances, people with MCS suffer significant limitations to their living environment and frequently to their workplace. This paper describes the current situation as regards MCS and the critical points in its case definition, which is still not generally agreed upon; this makes it difficult to recognize with certainty, especially, its precise relationship with work. Other problems arise in relation to the occupational physician's role in diagnosing and managing the worker with the disorder, the question of low levels of exposure to chemicals, and the best measures possible to prevent it. A diagnostic “route” is proposed, useful as a reference for the occupational physician who is often called in first to identify cases suspected of having this disease and to manage MCS workers. Work-related problems for people with MCS depend not only on occupational exposure but also on the incompatibility between their illness and their work. More occupational physicians need to be “sensitive” to MCS, so that these workers are recognized promptly, the work is adapted as necessary, and preventive measures are promoted in the workplace.

Chemical sensitivity: pathophysiology or pathopsychology?

BACKGROUND

Escalating numbers of people throughout the world are presenting to primary care physicians, allergists, and immunologists with myriad clinical symptoms after low-level exposure to assorted everyday chemicals such as smoke, perfumes, air fresheners, paints, glues, and other products. This clinical state is referred to by various diagnostic labels, including multiple chemical sensitivity disorder, environmental intolerance, chemical sensitivity (CS), and sensitivity-related illness, and has been the subject of much controversy within the health care community.

OBJECTIVE

The goal of this study was to provide a brief overview of the etiology, pathogenesis, clinical presentation, and management of CS. An evaluation of the medical community's response to this emerging diagnosis was also explored.

METHODS

This review was prepared by assessing available medical and scientific literature from MEDLINE, as well as by reviewing numerous books, toxicology journals, conference proceedings, government publications, and environmental health periodicals. A primary observation, however, is that there is limited scientific literature available on the issue of CS. The format of a traditional integrated review was chosen because such reviews play a pivotal role in scientific research and professional practice in medical issues with limited primary study and uncharted clinical territory.

RESULTS

The sensitization state of CS seems to be initiated by a significant toxic exposure, occurring as a 1-time event, or on surpassing a threshold of toxicity after toxicant accrual from repeated lower-level exposures. Once sensitized through a toxicant-induced loss of tolerance, individuals exposed to inciting triggers such as minute amounts of diverse everyday chemicals may experience various clinical and immune sequelae, sometimes involving lymphocyte, antibody, or cytokine responses. Precautionary avoidance of inciting triggers will prevent symptoms, and desensitization immunotherapy or immune suppression may improve symptoms in some cases. Sustained resolution of the CS state occurs after successful elimination of the accrued body burden of toxicants through natural mechanisms of toxicant bioelimination and/or interventions of clinical detoxification. Despite extensive clinical evidence to support the veracity of this clinical state, many members of the medical community are reluctant to accept this condition as a pathophysiologic disorder.

CONCLUSIONS

The emerging problem of ubiquitous adverse toxicant exposures in modern society has resulted in escalating numbers of individuals developing a CS disorder. As usual in medical history, iconoclastic ideas and emerging evidence regarding novel disease mechanisms, such as the pathogenesis of CS, have been met with controversy, resistance, and sluggish knowledge translation.