New methodology for specific inhalation challenges with occupational agents

<p>Abstract</p> <p>Background</p> <p>Inhalation challenges are used for diagnosing occupational asthma (OA). The initial methodology consisted of a "realistic" exposure without monitoring nor controlling exposure. Our aim was to design an equipment, called the GenaSIC, that allows the generation of various agents regardless of the formulation and to assess the feasibility of its use in patients investigated for OA.</p> <p>Results</p> <p>GenaSIC can generate lactose, flour, malt, isocyanates, formaldehyde and N-butyl acetate with precise and fairly stable concentrations. Using N-butyl-acetate as a control agent and real time measurement, we show that normal breathing has a negligible effect on the concentration. We exposed forty-four different subjects to a control agent and/or to a suspected occupational agent. Nineteen of the subjects were only exposed to N-butyl acetate as a control agent without experiencing any significant irritant effect (no significant changes in spirometry thereafter). Eight subjects who were exposed to both N-butyl acetate and formaldehyde did not show significant reactions. Seven subjects were exposed to dry particles (flour in six instances, malt in the other) and five showed immediate asthmatic reactions which changes in FEV1 from 20% to a maximum of 28%. Finally, ten subjects were exposed to isocyanates, four of whom showed a positive reaction, including one subject with immediate maximum changes in FEV1 of 22%.</p> <p>Conclusion</p> <p>GenaSIC offers the possibility of reliable and safe exposures to dry particles, formaldehyde and isocyanates in the investigation of OA.</p

Early incidence of occupational asthma among young bakers, pastry-makers and hairdressers: design of a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>Occupational exposures are thought to be responsible for 10-15% of new-onset asthma cases in adults, with disparities across sectors. Because most of the data are derived from registries and cross-sectional studies, little is known about incidence of occupational asthma (OA) during the first years after inception of exposure. This paper describes the design of a study that focuses on this early asthma onset period among young workers in the bakery, pastry making and hairdressing sectors in order to assess early incidence of OA in these "at risk" occupations according to exposure duration, and to identify risk factors of OA incidence.</p> <p>Methods/Design</p> <p>The study population is composed of subjects who graduated between 2001 and 2006 in these sectors where they experience exposure to organic or inorganic allergenic or irritant compounds (with an objective of 150 subjects by year) and 250 young workers with no specific occupational exposure. A phone interview focusing on respiratory and 'Ear-Nose-Throat' (ENT) work-related symptoms screen subjects considered as "possibly OA cases". Subjects are invited to participate in a medical visit to complete clinical and lung function investigations, including fractional exhaled nitric oxide (FE_NO) and carbon monoxide (CO) measurements, and to collect blood samples for IgE (Immunoglobulin E) measurements (total IgE and IgE for work-related and common allergens). Markers of oxidative stress and genetic polymorphisms exploration are also assessed. A random sample of 200 "non-cases" (controls) is also visited, following a nested case-control design.</p> <p>Discussion</p> <p>This study may allow to describ a latent period between inception of exposure and the rise of the prevalence of asthma symptoms, an information that would be useful for the prevention of OA. Such a time frame would be suited for conducting screening campaigns of this emergent asthma at a stage when occupational hygiene measures and adapted therapeutic interventions might be effective.</p> <p>Trial registration</p> <p>Clinical trial registration number is NCT01096537.</p

EAACI position paper on occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item

Proceedings of the first Jack Pepys Occupational Asthma Symposium.

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Do Low Molecular Weight Agents Cause More Severe Asthma than High Molecular Weight Agents?

INTRODUCTION:The aim of this study was to analyse whether patients with occupational asthma (OA) caused by low molecular weight (LMW) agents differed from patients with OA caused by high molecular weight (HMW) with regard to risk factors, asthma presentation and severity, and response to various diagnostic tests. METHODS:Seventy-eight patients with OA diagnosed by positive specific inhalation challenge (SIC) were included. Anthropometric characteristics, atopic status, occupation, latency periods, asthma severity according to the Global Initiative for Asthma (GINA) control classification, lung function tests and SIC results were analysed. RESULTS:OA was induced by an HMW agent in 23 patients (29%) and by an LMW agent in 55 (71%). A logistic regression analysis confirmed that patients with OA caused by LMW agents had a significantly higher risk of severity according to the GINA classification after adjusting for potential confounders (OR = 3.579, 95% CI 1.136-11.280; p = 0.029). During the SIC, most patients with OA caused by HMW agents presented an early reaction (82%), while in patients with OA caused by LMW agents the response was mainly late (73%) (p = 0.0001). Similarly, patients with OA caused by LMW agents experienced a greater degree of bronchial hyperresponsiveness, measured as the difference in the methacholine dose-response ratio (DRR) before and after SIC (1.77, range 0-16), compared with patients with OA caused by HMW agents (0.87, range 0-72), (p = 0.024). CONCLUSIONS:OA caused by LMW agents may be more severe than that caused by HMW agents. The severity of the condition may be determined by the different mechanisms of action of these agents