Sensitisation to cereal flour allergens is a major determinant of elevated exhaled nitric oxide in bakers

Objective Various studies of the usefulness of fractional exhaled nitric oxide (FeNO) in occupational settings remain inconclusive. The objective was to investigate the determinants of increased FeNO in bakery workers. Methods A cross-sectional study of 424 supermarket bakery workers used a questionnaire and serum specific IgE to wheat, rye and alpha-amylase. FeNO during the work shift were assessed using a hand-held portable sampling device (NIOX MINO). Results The median FeNO was 15 ppb, in atopics 21 ppb and current smokers 12 ppb. Increased FeNO was strongly associated with IgE to wheat independent of smoking and atopy status. In the multivariate model, IgE to wheat, current smoking, atopy and age were significantly associated with FeNO. Stratified analysis in a subgroup of atopic non-smokers demonstrated the strongest relationship between FeNO and various clinical endpoint such as wheat (OR=9.43) or rye (OR=11.76) sensitisation, work-related allergic rhinitis (OR=8.13) or asthma (OR=5.44), and probable baker's asthma (OR=6.72). Conclusions Sensitisation to cereal flour allergens rather than asthma symptoms is a major determinant of elevated FeNO among bakers. This relationship is modified by atopy and current smoking status.