Occupational respiratory allergy with bakery workers : relationships with wheat and fungal [alpha]-amylase aeroallergen exposure

In this thesis, results are presented of a cross-sectional epidemiological study among a few hundred bakery workers. Main focus was on the relationship between allergen exposure and the development of specific sensitization and respiratory allergy. Immunoassays were developed for measuring airborne allergens from wheat flour and fungalα-amylase, an enzymatic dough improver. A total of 571 personal inhalable dust samples were available from 230 workers. Wheat flour allergens were measured in 449 of these samples with an inhibition enzyme immuno assay, and an anti-wheat IgG 4 serum pool from bakery workers. Fungalα-amylase allergens were measured in 507 samples in a sandwich immunoassay, using affinity purified polyclonal rabbit IgG 4 antibodies. The validity and specificity of both assays were extensively tested. All bakery workers were categorized into groups, based on their job histories and the wheat orα-amylase allergen exposure levels of their job titles. Optimal grouping strategies were tested. For both orα-amylase and wheat allergens, a clear exposure- sensitization-relationship was found. Atopy appeared to be an important effect modifier of this relationship, and the steepest slope between allergen level and sensitization rate was found within the group of atopic workers. Twenty-three percent of the bakers reported work-related rhinitis or chest-tightness. Symptomatic bakers were divided into occupationally sensitized and non-sensitized workers. In both groups, a relation between allergen exposure and respiratory symptoms was found, but the slope of the relationship was steeper in sensitized bakers than in non-sensitized bakers.