Defining and investigating occupational asthma: a consensus approach

Oleoresin Capsicum (OC) Spray: An Assessment of Respiratory Health and its Management Following Accidental and Deliberate Exposures

Introduced into law enforcement in 1976, the oleoresin capsicum (OC) spray has been labeled as one of the most significant and radical developments in law enforcement. However, epidemiological research on OC health effects is deficient, receiving little public support. The major responses to acute exposure to OC spray can be found in the pulmonary system. The molecular mechanism(s) involved in the action of capsaicinoids, the active constituents in OC, are complex cascades of reactions which end up in necrosis or apoptosis. OC may also damage and deplete biological redox systems in the epithelial lining fluids and within cells and mitochondria, modifying structural proteins and nucleic acids and leading to enzyme inactivation. Since there are no characteristic laboratory tests available for identification or confirmation of OC exposure, and on the basis of prevailing data, reassessment of the health risks of OC exposures in vulnerable populations and in-depth study of the molecular mechanics of receptors is the need of the hour for the development of effective countermeasures. This review aims to consider evidence for adverse effects of OC spray used in ways comparable to their application by law enforcement personnel and civilians, with possible treatment recommendations that are precedent for improved management.

Airway inflammatory profile among cleaning workers from different workplaces

Background

Cleaning workers represent a significant proportion of the active population worldwide, with poor remuneration, particularly in developing countries. Despite this, they remain a relatively poorly studied occupational group. They are constantly exposed to agents that can cause symptoms and respiratory problems. This study aimed to evaluate upper airway inflammation in professional cleaning workers in three different occupational settings by comparing nasal cytology inflammation and clinical profiles.

Methods

We performed a cross-sectional study on the prevalence of upper airway inflammation and symptoms of asthma/rhinitis related to cleaning work, according to workplace. A total of 167 participants were divided into four groups: hospital, university, housekeeper and control. A nasal swab was collected for upper airway inflammation evaluation. Clinical profiles and respiratory symptom employee evaluations were performed using specific questionnaires (European Community Respiratory Health Survey—ECRS and the International Study of Asthma and Allergies in Childhood—ISAAC).

Results

Cleaning workers showed increased neutrophils and lymphocytes; the hospital and university groups showed increased macrophages compared to the housekeeper and control groups. The hospital and housekeeper groups showed increased eosinophils when they performed cleaning services for up to one year and reported having more asthma symptoms than the control group. Cleaning workers showed increased rhinitis symptoms. The university group showed increased rhinitis symptoms aggravated by the workplace compared with the hospital and housekeeper groups. Cleaning workers showed an increased affirmative response when directly asked about rhinitis symptoms compared to the control group.

Conclusions

Cleaning workers showed airway inflammation, asthma symptoms and rhinitis, regardless of the occupational environment to which they were exposed, as well as showed increased rhinitis and asthma symptoms. Hospital cleaning workers showed increased macrophages, lymphocytes and eosinophils compared to the others. The length of time spent performing cleaning work was not related to nasal inflammation or respiratory symptoms in this population. However, there were differences in workplaces. Registered on ClinicalTrials.gov. Trial registration number: NCT03311048. Registration date: 10.16.2017. Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01949-5.

Profiling of how nociceptor neurons detect danger - new and old foes

The host evolves redundant mechanisms to preserve physiological processing and homeostasis. These functions range from sensing internal and external threats, creating a memory of the insult and generating reflexes, which aim to resolve inflammation. Impairment in such functioning leads to chronic inflammatory diseases. By interacting through a common language of ligands and receptors, the immune and sensory nervous systems work in concert to accomplish such protective functions. Whilst this bidirectional communication helps to protect from danger, it can contribute to disease pathophysiology. Thus, the somatosensory nervous system is anatomically positioned within primary and secondary lymphoid tissues and mucosa to modulate immunity directly. Upstream of this interplay, neurons detect danger, which prompts the release of neuropeptides initiating (i) defensive reflexes (ranging from withdrawal response to coughing) and (ii) chemotaxis, adhesion and local infiltration of immune cells. The resulting outcome of such neuro-immune interplay is still ill-defined, but consensual findings start to emerge and support neuropeptides not only as blockers of T_H 1-mediated immunity but also as drivers of T_H 2 immune responses. However, the modalities detected by nociceptors revealed broader than mechanical pressure and temperature sensing and include signals as various as cytokines and pathogens to immunoglobulins and even microRNAs. Along these lines, we aggregated various dorsal root ganglion sensory neuron expression profiling datasets supporting such wide-ranging sensing capabilities to help identifying new danger detection modalities of these cells. Thus, revealing unexpected aspects of nociceptor neuron biology might prompt the identification of novel drivers of immunity, means to resolve inflammation and strategies to safeguard homeostasis.

Clinically relevant subgroups in COPD and asthma

As knowledge of airways disease has grown, it has become apparent that neither chronic obstructive pulmonary disease (COPD) nor asthma is a simple, easily defined disease. In the past, treatment options for both diseases were limited; thus, there was less need to define subgroups. As treatment options have grown, so has our need to predict who will respond to new drugs. To date, identifying subgroups has been largely reported by detailed clinical characterisation or differences in pathobiology. These subgroups are commonly called "phenotypes"; however, the problem of defining what constitutes a phenotype, whether this should include comorbid diseases and how to handle changes over time has led to the term being used loosely. In this review, we describe subgroups of COPD and asthma patients whose clinical characteristics we believe have therapeutic or major prognostic implications specific to the lung, and whether these subgroups are constant over time. Finally, we will discuss whether the subgroups we describe are common to both asthma and COPD, and give some examples of how treatment might be tailored in patients where the subgroup is clear, but the label of asthma or COPD is not.

Air quality and temperature effects on exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) is exaggerated constriction of the airways usually soon after cessation of exercise. This is most often a response to airway dehydration in the presence of airway inflammation in a person with a responsive bronchial smooth muscle. Severity is related to water content of inspired air and level of ventilation achieved and sustained. Repetitive hyperpnea of dry air during training is associated with airway inflammatory changes and remodeling. A response during exercise that is related to pollution or allergen is considered EIB. Ozone and particulate matter are the most widespread pollutants of concern for the exercising population; chronic exposure can lead to new-onset asthma and EIB. Freshly generated emissions particulate matter less than 100 nm is most harmful. Evidence for acute and long-term effects from exercise while inhaling high levels of ozone and/or particulate matter exists. Much evidence supports a relationship between development of airway disorders and exercise in the chlorinated pool. Swimmers typically do not respond in the pool; however, a large percentage responds to a dry air exercise challenge. Studies support oxidative stress mediated pathology for pollutants and a more severe acute response occurs in the asthmatic. Winter sport athletes and swimmers have a higher prevalence of EIB, asthma and airway remodeling than other athletes and the general population. Because of fossil fuel powered ice resurfacers in ice rinks, ice rink athletes have shown high rates of EIB and asthma. For the athlete training in the urban environment, training during low traffic hours and in low traffic areas is suggested.

The ordinary work environment increases symptoms from eyes and airways in mild steel welders

Purpose

We aimed to follow diary-registered symptoms from eyes and airways in mild steel welders and relate them to different exposure measures. Furthermore, we would clarify the influence of possible effect modifiers.

Methods

Non-smoking welders with (N = 74) and without (N = 32) work-related symptoms the last month were enroled. Symptoms and work tasks each day for three two-week periods during 1 year were obtained. Respirable dust (RD) was measured 1 day each period for each worker. The personal daily exposure was assessed as: (1) days at work, (2) welding time and (3) estimates of RD from welding and grinding, calculated from diary entries and measurements.

Results

Only 9.2 % of the particle measurements exceed the Swedish occupational exposure limit (OEL; 5 mg/m³). Days at work increased the risk of symptoms studied: eyes: 1.79 (1.46–2.19), nasal: 2.16 (1.81–2.58), dry cough: 1.50 (1.23–1.82) and wheezing and/or dyspnoea: 1.27 (1.03–1.56; odds ratio, 95 % confidence interval). No clear dose–response relationships were found for the other exposure estimates. Eye symptoms increased by number of years welding. Nasal symptoms and dry cough increased having forced expiratory volume in first second below median at baseline. Wheezing and/or dyspnoea increased in winter, by number of years welding, having a negative standard skin-prick test and having a vital capacity above median at baseline.

Conclusion

The current Swedish OEL may not protect welders against eye and airway symptoms. The results add to the evidence that welders should be offered regular medical surveillance from early in the career.

Transient receptor potential channels and occupational exposure

PURPOSE OF REVIEW

The discovery that a number of transient receptor potential (TRP) channels are expressed in a subpopulation of primary sensory neurons innervating the upper and lower airways as well as in nonneuronal cells in the airways and lungs has initiated a quest for the understanding of their role in the physiology and pathophysiology of the respiratory tract.

RECENT FINDINGS

Various members of the TRP vanilloid subfamily (TRPV1, TRPV4) and the TRP ankyrin 1 (TRPA1), because of their localization in peptidergic sensory neurons, promote airway neurogenic inflammation. In particular, TRPA1, which is gated by oxidative and nitrative stress byproducts, has been found to mediate inflammatory responses produced by an unprecedented series of toxic and irritant agents produced by air pollution, contained in cigarette smoke, and produced by accidental events at the workplace. The observation that reactive molecules endogenously produced in the airways/lungs of asthma, work-related asthma, and chronic obstructive pulmonary disease target TRPA1 underscores the primary role of the TRPA1 channel in these conditions.

SUMMARY

Identification of TRP channels, and especially TRPA1, as major targets of oxidative/nitrative stress and a variety of irritant environmental agents supports the hypothesis that neurogenic inflammation plays an important role in work-related inflammatory diseases and that antagonists for such channels may be novel therapeutic options for the treatment of these diseases.

EAACI position paper: irritant-induced asthma

The term irritant-induced (occupational) asthma (IIA) has been used to denote various clinical forms of asthma related to irritant exposure at work. The causal relationship between irritant exposure(s) and the development of asthma can be substantiated by the temporal association between the onset of asthma symptoms and a single or multiple high-level exposure(s) to irritants, whereas this relationship can only be inferred from epidemiological data for workers chronically exposed to moderate levels of irritants. Accordingly, the following clinical phenotypes should be distinguished within the wide spectrum of irritant-related asthma: (i) definite IIA, that is acute-onset IIA characterized by the rapid onset of asthma within a few hours after a single exposure to very high levels of irritant substances; (ii) probable IIA, that is asthma that develops in workers with multiple symptomatic high-level exposures to irritants; and (iii) possible IIA, that is asthma occurring with a delayed-onset after chronic exposure to moderate levels of irritants. This document prepared by a panel of experts summarizes our current knowledge on the diagnostic approach, epidemiology, pathophysiology, and management of the various phenotypes of IIA.

Monitoring vital signs: development of a modified early warning scoring (MEWS) system for general wards in a developing country

Objective

The aim of the study was to develop and validate, by consensus, the construct and content of an observations chart for nurses incorporating a modified early warning scoring (MEWS) system for physiological parameters to be used for bedside monitoring on general wards in a public hospital in South Africa.

Methods

Delphi and modified face-to-face nominal group consensus methods were used to develop and validate a prototype observations chart that incorporated an existing UK MEWS. This informed the development of the Cape Town ward MEWS chart.

Participants

One specialist anaesthesiologist, one emergency medicine specialist, two critical care nurses and eight senior ward nurses with expertise in bedside monitoring (N = 12) were purposively sampled for consensus development of the MEWS. One general surgeon declined and one neurosurgeon replaced the emergency medicine specialist in the final round.

Results

Five consensus rounds achieved ≥70% agreement for cut points in five of seven physiological parameters respiratory and heart rates, systolic BP, temperature and urine output. For conscious level and oxygen saturation a relaxed rule of <70% agreement was applied. A reporting algorithm was established and incorporated in the MEWS chart representing decision rules determining the degree of urgency. Parameters and cut points differed from those in MEWS used in developed countries.

Conclusions

A MEWS for developing countries should record at least seven parameters. Experts from developing countries are best placed to stipulate cut points in physiological parameters. Further research is needed to explore the ability of the MEWS chart to identify physiological and clinical deterioration.

Developing an international Pseudomonas aeruginosa reference panel

Pseudomonas aeruginosa is a major opportunistic pathogen in cystic fibrosis (CF) patients and causes a wide range of infections among other susceptible populations. Its inherent resistance to many antimicrobials also makes it difficult to treat infections with this pathogen. Recent evidence has highlighted the diversity of this species, yet despite this, the majority of studies on virulence and pathogenesis focus on a small number of strains. There is a pressing need for a P. aeruginosa reference panel to harmonize and coordinate the collective efforts of the P. aeruginosa research community. We have collated a panel of 43 P. aeruginosa strains that reflects the organism's diversity. In addition to the commonly studied clones, this panel includes transmissible strains, sequential CF isolates, strains with specific virulence characteristics, and strains that represent serotype, genotype or geographic diversity. This focussed panel of P. aeruginosa isolates will help accelerate and consolidate the discovery of virulence determinants, improve our understanding of the pathogenesis of infections caused by this pathogen, and provide the community with a valuable resource for the testing of novel therapeutic agents.

Acute pulmonary function change associated with work on large dairies in California

OBJECTIVE

To study whether dairy workers in California have lower baseline and greater cross-shift decrements in lung function than control employees.

METHODS

A cross-sectional study of 210 dairy and 47 control workers who completed questionnaires and spirometry before and after the work shift.

RESULTS

Dairy work was associated with mean baseline differences of -0.132 L (P = 0.07) and -0.131 L (P = 0.13) in forced expiratory volume in 1 second and forced vital capacity, respectively, compared with control employees, adjusting for age, height, smoking status, and days back at work since last day off. Dairy work was associated with a mean cross-shift difference of -65.2 mL (P = 0.02) and -103.1 mL (P < 0.01) in forced expiratory volume in 1 second and forced vital capacity, respectively, adjusting for smoking status and work-shift time.

CONCLUSIONS

Dairy work in California was associated with mild acute airway obstruction. The unclear long-term effect of dairy work in California merits further investigation.

RADS and its variants: asthma by another name

This article describes the different clinical variants of irritant-induced asthma, specifically focusing on high-dose irritant-induced asthma and irritant-induced work-exacerbated asthma, as well as reviews known causes, addresses the often adverse medical and socioeconomic outcomes of this complex condition, and considers issues of causation from an occupational and environmental medicine perspective.

Concise guidance: diagnosis, management and prevention of occupational asthma

This concise guidance, prepared for physicians, summarises the British Occupational Health Research Foundation guideline for the prevention, identification and management of occupational asthma. Approximately one in six people of working age who develop asthma have work-related asthma, where work has either caused or aggravated their disease. Physicians who assess working adults with asthma need to ask the patient about their job and the materials they work with, and be aware of those that carry particular risks; they should also ask whether symptoms improve regularly on days away from work. A diagnosis of occupational asthma (ie asthma caused by work) should not be made on the basis of history alone, but be supported by immunological and physiological investigations of proven diagnostic benefit. Following a validated diagnosis of occupational asthma, physicians should recommend early avoidance of further exposure, because this offers the best chance of complete recovery. If appropriate and timely interventions are not taken, the prognosis of occupational asthma is poor, with only approximately one-third of workers achieving full symptomatic recovery.

Irritant-induced airway disorders

Thousands of persons experience accidental high-level irritant exposures each year but most recover and few die. Irritants function differently than allergens because their actions proceed nonspecifically and by nonimmunologic mechanisms. For some individuals, the consequence of a single massive exposure to an irritant, gas, vapor or fume is persistent airway hyperresponsiveness and the clinical picture of asthma, referred to as reactive airways dysfunction syndrome (RADS). Repeated irritant exposures may lead to chronic cough and continual airway hyperresponsiveness. Cases of asthma attributed to repeated irritant-exposures may be the result of genetic and/or host factors.

Definitions and classification of work-related asthma

The workplace can trigger or induce asthma and cause the onset of different types of work-related asthma (WRA). Based on current knowledge of clinical features, pathophysiologic mechanisms, and evidence supporting a causal relationship, the following conditions should be distinguished in the spectrum of WRA: (1) immunologic occupational asthma (OA), (2) nonimmunologic OA, (3) work-exacerbated asthma, and (4) variant syndromes, including eosinophilic bronchitis, potroom asthma, and asthmalike disorders caused by organic dusts. The rationale, issues, and controversies relating to this approach are critically reviewed to stimulate the development of a consensus on operational definitions of the various phenotypes of WRA.

Non-sensitising air pollution at workplaces and adult-onset asthma in the beginning of this millennium

PURPOSE

This case-control study was undertaken to elucidate the controversy concerning whether low-level, long-term exposure to non-sensitising air pollution at workplaces may cause asthma.

METHODS

A case-control study of 192 adult-onset asthma cases aged 20-65 years and 323 controls was conducted in the southeast of Sweden. Cases were identified from computerised registers from the region, diagnosed 2000-2004 and diagnoses were confirmed via medical files. Referents were randomised from the population register of the region. Exposure was monitored by a 16-page questionnaire. Special attention was devoted to identifying and in the final analyses excluding subjects exposed to sensitising agents.

RESULTS

Three years or more of occupational exposure to air pollution from dust, smoke, fumes or vapours before the year of diagnosis by analyses adjusting for age yielded an increased risk for asthma (OR = 2.3, 95% CI 1.2-4.2) in men, while in women, no risk was seen. In a multiple logistic regression analysis in men without allergy in childhood, a significant risk was seen (OR = 2.8, 95% CI 1.07-7.4), when subjects exposed to identified allergens were excluded. In women, no excess risk was observed from occupational air pollution.

CONCLUSION

The results of this study support an association between occupational exposure to low level non-sensitising air pollution and adult-onset asthma in men.

Occupational asthma: review of assessment, treatment, and compensation

Occupational asthma refers to asthma induced by exposure in the working environment to airborne dusts, vapors, or fumes, with or without preexisting asthma. Potential triggers of occupational asthma are diverse and involve a variety of postulated mechanisms. After confirming the presence of asthma, diagnosis hinges on obtaining a detailed and accurate occupational and environmental history and documenting a temporal association of symptoms or signs with workplace exposure. Management of occupational asthma centers on prescribing standard asthma therapies in conjunction with instituting preventive strategies, such as appropriate avoidance of environmental triggers, providing work restrictions, and using environmental controls and/or personal respiratory protection. If a worker is determined to be ill or injured, there are a variety of compensation systems that are designed to protect workers financially from disability related to respiratory impairments; however, the administrative process is frequently difficult to navigate for patients and their providers. Focusing on obtaining a detailed occupational and environmental history, establishing clear objective data to substantiate illness, and estimating or apportioning workplace contribution to the condition is important for the diagnosis and treatment of this relatively common form of asthma.

Methyl methacrylate and respiratory sensitization: a critical review

Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants. The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer.

Sensory detection and responses to toxic gases: mechanisms, health effects, and countermeasures

The inhalation of reactive gases and vapors can lead to severe damage of the airways and lung, compromising the function of the respiratory system. Exposures to oxidizing, electrophilic, acidic, or basic gases frequently occur in occupational and ambient environments. Corrosive gases and vapors such as chlorine, phosgene, and chloropicrin were used as warfare agents and in terrorist acts. Chemical airway exposures are detected by the olfactory, gustatory, and nociceptive sensory systems that initiate protective physiological and behavioral responses. This review focuses on the role of airway nociceptive sensory neurons in chemical sensing and discusses the recent discovery of neuronal receptors for reactive chemicals. Using physiological, imaging, and genetic approaches, Transient Receptor Potential (TRP) ion channels in sensory neurons were shown to respond to a wide range of noxious chemical stimuli, initiating pain, respiratory depression, cough, glandular secretions, and other protective responses. TRPA1, a TRP ion channel expressed in chemosensory C-fibers, is activated by almost all oxidizing and electrophilic chemicals, including chlorine, acrolein, tear gas agents, and methyl isocyanate, the highly noxious chemical released in the Bhopal disaster. Chemicals likely activate TRPA1 through covalent protein modification. Animal studies using TRPA1 antagonists or TRPA1-deficient mice confirmed the role of TRPA1 in chemically induced respiratory reflexes, pain, and inflammation in vivo. New research shows that sensory neurons are not merely passive sensors of chemical exposures. Sensory channels such as TRPA1 are essential for maintenance of airway inflammation in asthma and may contribute to the progression of airway injury following high-level chemical exposures.

Chlorine gas inhalation: human clinical evidence of toxicity and experience in animal models

Humans can come into contact with chlorine gas during short-term, high-level exposures due to traffic or rail accidents, spills, or other disasters. By contrast, workplace and public (swimming pools, etc.) exposures are more frequently long-term, low-level exposures, occasionally punctuated by unintentional transient increases. Acute exposures can result in symptoms of acute airway obstruction including wheezing, cough, chest tightness, and/or dyspnea. These findings are fairly nonspecific, and might be present after exposures to a number of inhaled chemical irritants. Clinical signs, including hypoxemia, wheezes, rales, and/or abnormal chest radiographs may be present. More severely affected individuals may suffer acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS). Up to 1% of exposed individuals die. Humidified oxygen and inhaled beta-adrenergic agents are appropriate therapies for victims with respiratory symptoms while assessments are underway. Inhaled bicarbonate and systemic or inhaled glucocorticoids also have been reported anecdotally to be beneficial. Chronic sequelae may include increased airways reactivity, which tends to diminish over time. Airways hyperreactivity may be more of a problem among those survivors that are older, have smoked, and/or have pre-existing chronic lung disease. Individuals suffering from irritant-induced asthma (IIA) due to workplace exposures to chlorine also tend to have similar characteristics, such as airways hyperresponsiveness to methacholine, and to be older and to have smoked. Other workplace studies, however, have indicated that workers exposed to chlorine dioxide/sulfur dioxide have tended to have increased risk for chronic bronchitis and/or recurrent wheezing attacks (one or more episodes) but not asthma, while those exposed to ozone have a greater incidence of asthma. Specific biomarkers for acute and chronic exposures to chlorine gas are currently lacking. Animal models for chlorine gas inhalation have demonstrated evidence of oxidative injury and inflammation. Early epithelial injury, airways hyperresponsiveness, and airway remodeling, likely diminishing over time, have been shown. As in humans, ALI/ARDS can occur, becoming more likely when the upper airways are bypassed. Inhalation models of chlorine toxicity provide unique opportunities for testing potential pharmacologic rescue agents.

Surveillance of work-related asthma in new york state

OBJECTIVE

The objective of this paper is to determine the percent of adults with asthma attributable to work and describe characteristics of the work-related asthma population in New York State. Sociodemographic and control characteristics of those with and without work-related asthma are compared.

METHODS

Data from three population-based surveys and one case-based surveillance system were analyzed. Work-relatedness of asthma was determined by self-report for the population-based surveys and by physician report for the case-based system. Self-reported sociodemographic and control characteristics were analyzed for the population-based surveys by work-relatedness.

RESULTS

The percent of work-relatedness among adults with current asthma in New York State ranged from 10.6% to 44.5%. Significantly more adults with work-related asthma had poorly controlled asthma than those without work-related asthma. More adults with work-related asthma also tended to be employed in the manufacturing, educational services, and public administration industries than the general population. The most frequently reported exposure was dust.

CONCLUSIONS

Adults with work-related asthma have decreased control and adverse socioeconomic impacts compared to those with asthma that is not work-related. Increased recognition and physician reporting is necessary to further prevent the impact of work-related exposures.

The respiratory health of swimmers

Regular physical activity is recognized as an effective health promotion measure. Among various activities, swimming is preferred by a large portion of the population. Although swimming is generally beneficial to a person's overall health, recent data suggest that it may also sometimes have detrimental effects on the respiratory system. Chemicals resulting from the interaction between chlorine and organic matter may be irritating to the respiratory tract and induce upper and lower respiratory symptoms, particularly in children, lifeguards and high-level swimmers. The prevalence of atopy, rhinitis, asthma and airway hyper-responsiveness is increased in elite swimmers compared with the general population. This may be related to the airway epithelial damage and increased nasal and lung permeability caused by the exposure to chlorine subproducts in indoor swimming pools, in association with airway inflammatory and remodelling processes. Currently, the recommended management of swimmers' respiratory disorders is similar to that of the general population, apart from the specific rules for the use of medications in elite athletes. Further studies are needed to better understand the mechanisms related to the development or worsening of respiratory disorders in recreational or competitive swimmers, to determine how we can optimize treatment and possibly help prevent the development of asthma.

Variability in the diagnosis of occupational asthma and implications for clinical practice

PURPOSE OF REVIEW

The purpose of this review is to provide a summary of recent evidence relating to occupational asthma diagnosis.

RECENT FINDINGS

Recent evidence suggests that whilst prolonged asthmagen exposure worsens the prognosis, many steps in the diagnostic process are problematic for workers with possible occupational asthma. Certain workers suffer delay prior to specialist assessment, and assessment itself may be of variable quality. Emerging evidence suggests that whilst experts agree about certain aspects of case assessment, there is still likely to be variation in clinical practice. Implications of this variation for the workers assessed are relatively under researched.

SUMMARY

Future research needs to focus not only on improving diagnostic testing, but also on improving consistency and agreement over diagnosis.

Methods for the prediction of low-molecular-weight occupational respiratory sensitizers

PURPOSE OF REVIEW

There is recognition that respiratory sensitization is an occupational hazard of high concern. Despite international regulatory requirements there is no established protocol for the efficient prospective identification of chemical respiratory sensitizers. We review the predictive behaviour of available methods and suggest a possible high-throughput protocol.

RECENT FINDINGS

Animal or in-vitro tests specific to respiratory exposure and resulting in direct asthma-related outcomes have not been developed, although the use of a local lymph node assay originally designed for skin sensitization has been advocated in a respiratory context. Various methods have been used to develop quantitative structure-activity relationship models for prediction of low-molecular-weight organic chemical respiratory sensitizers. The estimated negative predictive value for all of the published models is 1, but their differences in positive predictive value can be exploited.

SUMMARY

The most pragmatic as well as valid approach for screening large numbers of industrial chemicals for respiratory sensitization hazard is likely to consist of an algorithm starting with quantitative structure-activity relationship models. Further corroboration from animal or human data, however, may be required for chemicals with a positive result by quantitative structure-activity relationship.

Chronic cough – occupational considerations

Chronic cough is a common symptom in a wide range of respiratory conditions, and may also occur as a result of upper airway or gastro-esophageal problems. Whilst chronic cough of any cause may be exacerbated by work, in some cases it has a direct occupational cause, resulting from a harmful acute or chronic workplace exposure. Such occupational conditions may only be suspected by taking a detailed occupational history, and directly asking employed patients whether their cough improves away from work. Early and accurate diagnosis, linked with tailored drug therapy, modification of workplace exposures, and expert compensation advice is likely to offer the best outcome for this group of patients.

Diagnosis and management of work-related asthma: American College Of Chest Physicians Consensus Statement

BACKGROUND

A previous American College of Chest Physicians Consensus Statement on asthma in the workplace was published in 1995. The current Consensus Statement updates the previous one based on additional research that has been published since then, including findings relevant to preventive measures and work-exacerbated asthma (WEA).

METHODS

A panel of experts, including allergists, pulmonologists, and occupational medicine physicians, was convened to develop this Consensus Document on the diagnosis and management of work-related asthma (WRA), based in part on a systematic review, that was performed by the University of Alberta/Capital Health Evidence-Based Practice and was supplemented by additional published studies to 2007.

RESULTS

The Consensus Document defined WRA to include occupational asthma (ie, asthma induced by sensitizer or irritant work exposures) and WEA (ie, preexisting or concurrent asthma worsened by work factors). The Consensus Document focuses on the diagnosis and management of WRA (including diagnostic tests, and work and compensation issues), as well as preventive measures. WRA should be considered in all individuals with new-onset or worsening asthma, and a careful occupational history should be obtained. Diagnostic tests such as serial peak flow recordings, methacholine challenge tests, immunologic tests, and specific inhalation challenge tests (if available), can increase diagnostic certainty. Since the prognosis is better with early diagnosis and appropriate intervention, effective preventive measures for other workers with exposure should be addressed.

CONCLUSIONS

The substantial prevalence of WRA supports consideration of the diagnosis in all who present with new-onset or worsening asthma, followed by appropriate investigations and intervention including consideration of other exposed workers.