Exposure-response relations of á-amylase sensitisation in British bakeries and flour mills

Objectives—To describe the levels of exposure to fungal á-amylase in British bakeries and flour mills, and to describe the relation between exposure to á-amylase and sensitisation to fungal á-amylase. Methods—495 personal flour dust samples were taken in seven British bakeries and flour mills and analysed for á-amylase with an immunoassay. Workers at the sites were asked to fill out questionnaires on work related symptoms, smoking history, and work history, and they were skin prick tested with common allergens and fungal á-amylase to assess sensitisation. Results—Exposure to high concentrations of á-amylase occur in a few areas of British bakeries and flour mills, and there can be considerable diVerences in exposures to á-amylase between sites and between exposure groups, and even within similar exposure groups from diVerent sites. Exposure to the highest concentrations of á-amylase was found in the dispensing and mixing areas of the bakeries (geometric mean (GM) 39.7 ng/m). Exposure to á-amylase showed only a moderate correlation with concentrations of dust (r=0.42) and flour aeroallergen (r=0.46). The results also showed a relation between exposure to á-amylase and sensitisation to fungal á-amylase (prevalence ratio (PR) for medium exposure 3.9, 95% confidence interval (95% CI) 0.8 to 20.2, PR for high exposure 9.9, 95% CI 2.8 to 34.6) compared with the low exposure category). Atopic subjects had an increased risk of sensitisation, but this was not significant. Conclusion—This study suggests that exposure to á-amylase is a considerable health risk in British bakeries and flour mills. A small proportion of workers are exposed to á-amylase at concentrations that result in high rates of sensitisation. A reduction in exposure to á-amylase is likely to reduce this risk. (Occup Environ Med 1999;56:197–201)