Exhaled nitric oxide and screening for occupational asthma in two at-risk sectors: bakery and hairdressing.

BACKGROUND: Fractional exhaled nitric oxide (FENO) levels are increasingly being used in the diagnosis and management of asthma. However, this indicator has rarely been used to detect occupational asthma. OBJECTIVE: To examine non-invasive methods to estimate airway inflammation. METHODS: A nested case-control study was conducted among a retrospective cohort of young workers in the bakery, pastry-making and hairdressing industries. Subjects underwent a clinical examination during a medical visit. Blood samples were collected and FENO levels measured. Cases were subjects diagnosed as suffering from 'confirmed' or 'probable' occupational asthma. RESULTS: Of the 178 workers included in the study, 19 were cases. In univariate analysis, FENO was associated with case/control status, and height and smoking status. In a multiple linear regression model, case/control status (P < 0.001), height (P = 0.006) and smoking status (P < 0.001) remained independent risk factors for variations in FENO levels. Good or fair sensitivity of respectively around 80% and 70% can be achieved using low FENO thresholds (8.5 and 10.5 ppb, respectively). FENO >8.5 ppb and a positive clinical examination increases specificity without loss of sensitivity (to 80.5% and 79.0%, respectively). CONCLUSION: This study suggests that FENO measurements alone cannot be considered a useful screening test for occupational asthma. Further investigations are needed to investigate the use of combined FENO and questionnaire or repeated measures.

Prevalence of IgE against neuromuscular blocking agents in hairdressers and bakers.

BACKGROUND: Allergic IgE-mediated reactions to neuromuscular blocking agents (NMBAs) are the main cause of immediate hypersensitivity reactions in anaesthesia; their predominant occurrence in the absence of previous exposure to NMBAs suggests a risk related to environmental exposure. OBJECTIVE: To investigate the prevalence of specific IgE to quaternary ammonium ions in two populations professionally exposed to quaternary ammonium compounds, in the north-eastern France. METHODS: The study had a retrospective follow-up design whereby apprentices were assessed after their 2-year training period as apprentices. The professionally exposed hairdresser populations (n = 128) were compared with baker/pastry makers (n = 108) and 'non-exposed' matched control subjects (n = 379). RESULTS: We observed a 4.6-fold higher frequency of positive IgE against quaternary ammonium ions in hairdressers (HD), compared with baker/pastry makers (BP) and control (C) groups. The competitive inhibition of quaternary ammonium Sepharose radioimmunoassay (QAS-IgE RIA) with succinylcholine was significantly higher in HD, compared with BP and C groups, with inhibition percentage of 66.2 ± 7.4, 39.7 ± 6.0 and 43.8 ± 9.9, respectively (P < 0.001). The specific IgE against quaternary ammonium ions recognized also two compounds widely used by hairdressers, benzalkonium chloride and polyquaternium-10, in competitive inhibition of IgE RIA. When considering the whole study population, hairdresser professional exposure and total IgE > 100 kU/L were the two significant predictors of IgE-sensitization against quaternary ammonium ions in the multivariate analysis of a model that included age, sex, professional exposure, increased concentration of total IgE (IgE > 100 kU/L) and positive IgE against prevalent allergens (Phadiatop(®) ; P = 0.019 and P = 0.001, respectively). CONCLUSION AND CLINICAL RELEVANCE: The exposure to hairdressing professional occupational factors increases IgE-sensitization to NMBAs and quaternary ammonium ion compounds used in hairdressing. Besides the pholcodine hypothesis, our study suggests that repetitive exposure to quaternary ammonium compounds used in hairdressing is a risk factor for NMBAs sensitization.

Early incidence of occupational asthma is not accelerated by atopy in the bakery/pastry and hairdressing sectors.

SETTING: Occupational asthma (OA) is most likely to develop in the very early years of exposure. OBJECTIVE: To describe the early incidence of OA among bakers/pastry-makers (BP) and hairdressers and to explore the role of atopy. DESIGN: Following a retrospective follow-up design, subjects were invited to undergo telephone interviews. Those who declared work-related respiratory or rhinitis symptoms and a sample group of others were offered a medical visit for OA investigations. Data from interviews and from medical visits were used to estimate the incidence of OA according to increasing durations of exposure. RESULTS: A total of 866 subjects were interviewed (mean age 25.3 years, 43.8% females), of whom 282 underwent a medical visit. Total estimated incidence rates of 'confirmed or probable' OA during the first 12 years of exposure were high in BP (2.63 per 100 person-years [py]) and in hairdressers (0.58/100 py), particularly in the first 4 years. Atopy is a strong risk factor for incidence among BP but, irrespective of the occupational sector, it does not influence the timing of OA symptoms. CONCLUSION: OA symptoms occur soon after the start of exposure. Our results suggest that atopy does not precipitate the occurrence of symptoms in two different allergen exposure settings.