Respiratory symptoms, lung function, and sensitisation to flour in a British bakery.

Abstract

A survey of dust exposure, respiratory symptoms, lung function, and response to skin prick tests was conducted in a modern British bakery. Of the 318 bakery employees, 279 (88%) took part. Jobs were ranked from 0 to 10 by perceived dustiness and this ranking correlated well with total dust concentration measured in 79 personal dust samples. Nine samples had concentrations greater than 10 mg/m3, the exposure limit for nuisance dust. All participants completed a self administered questionnaire on symptoms and their relation to work. FEVy and FVC were measured by a dry wedge spirometer and bronchial reactivity to methacholine was estimated. Skin prick tests were performed with three common allergens and with 11 allergens likely to be found in bakery dust, including mites and moulds. Of the participants in the main exposure group, 35% reported chest symptoms which in 13% were work related. The corresponding figures for nasal symptoms were 38% and 19%. Symptoms, lung function, bronchial reactivity, and response to skin prick tests were related to current or past exposure to dust using logistic or linear regression analysis as appropriate. Exposure rank was significantly associated with most of the response variables studied. The study shows that respiratory symptoms and sensitisation are common, even in a modern bakery.Occupational asthma and rhinitis occur in bakers' and the environmental agents responsible appear to be components of the grain itself" or grain contaminants, such as mites, weevils, and moulds"7 The relative importance of these potential allergens may vary according to the source of the flour, conditions of storage, and intensity of exposure. Recent papers describing grain components as important allergens have come from Australia,24 where grain has a low moisture content. A higher moisture content, or storage ofgrain or flour for long periods, may promote the growth of contaminant micro-organisms, mites, and insects. Materials added to flour before baking, such as yeast and amylase, derived from Aspergillus species,' may also be allergenic. As many as a third ofbakers and grain workers may show evidence of sensitisation,9" which appears to be related to intensity and duration of exposure in the industry as well as to host factors, such as atopy." 12 Mechanisms involving IgE and the mast cell have been implicated,'2 13 but precipitins to components of flour have also been identified' and non-immunological processes, such as direct activation of complement pathways, may be involved.'4Apart from case reports, there is little information about asthma and sensitisation in British bakers. This study was designed to (a) describe the levels of exposure to bakery dust in a modern British bakery, (b) estimate the prevalence of symptoms and sensitisation in the workforce of the bakery, and (c) explore relations between indices of exposure and response. Methods STUDY DESIGN AND SUBJECTSThe study was a cross sectional survey of current employees conducted over six consecutive days and nights. All current...

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