Sensitisation to occupational allergens in bakers' asthma and rhinitis: a case-referent study.

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.