Objectives: To study the importance of sensitisation to occupational allergens for the occurrence of asthma and rhinitis in bakers.
Methods: This is a nested clinical case-referent study of bakers based on a cohort of Swedish former bakery students. Cases were asthmatic ( n=25) or rhinitic bakers ( n=20). Randomly selected bakers ( n=44) were referents. All subjects underwent skin prick tests (SPTs) with common allergens, flours, fungal alpha-amylase and the storage mite L. destructor. Indices of airway inflammation were assessed in serum and the nose.
Results: Seven of the asthmatics and eight of the rhinitics reported onset of disease during bakery work. Flour SPTs were positive in 43% of the asthmatics or rhinitics vs 16% of referents. The corresponding figures for alpha-amylase were 29%, 25%, and 7%. The odds ratio, adjusted for atopy, for an SPT positive to flour or alpha-amylase for asthmatics with onset during bakery work was 5.8 (95% confidence interval 1.1-32), and 2.6 (0.4-16) for the corresponding rhinitics. The positive predictive value of sensitisation to flour or alpha-amylase in relation to a clinical diagnosis of asthma or rhinitis was 71%. Sensitisation to L. destructor was rare. The indices of airway inflammation were similar in cases and in referents.
Conclusions: Bakers' asthma is associated with sensitisation to flour and/or alpha-amylase, atopy taken into account. A similar association was suggested in bakers' rhinitis. Indices of airway inflammation were of low predictive value for detecting bakers' asthma or rhinitis in this study.