Allergen and dust exposure as determinants of work-related symptoms and sensitization in a cohort of flour-exposed workers; a case-control analysis

Objectives: To estimate the incidence of specific IgE sensitization and all ergic respiratory symptoms among UK bakery and flour mill workers; and to e xamine the roles of flour aeroallergen and total dust exposures in determin ing these outcomes. Methods: A cohort of 300 new employees, without previous occupational expos ure to flour, were followed prospectively for a median (range) of 40 (1-91) months. Cases-defined as those developing work-related symptoms or a posit ive skin prick test to hour or alpha -amylase during follow up-were compare d with controls, matched for duration of employment. Exposures to hour aero allergen and total inhalable dust were estimated using a questionnaire and personal sampling techniques. Results: Incidence rates for work-related eye/nose and chest symptoms were 11.8 and 4.1 cases per 100 person years (py), respectively. Few er employee s developed positive skin prick tests to hour (2.2 cases per 100 py) or alp ha -amylase (2.5 cases per 100 py), Positive skin tests to occupational all ergens were more common among those with new work-related symptoms. There w ere clear relationships between the risks of developing work-related sympto ms or a positive skin prick test and three categories of estimated exposure to total dust or hour aeroallergen. Atopic employees were more likely to d evelop a positive skin prick test-but not work-related symptoms, These find ings were unaffected by age, sex or cigarette smoking. Conclusions: In this population, many work-related symptoms which develop a fter first employment in modern UK bakeries or hour mills were not accompan ied by evidence of IgE sensitization to flour or alpha -amylase, Although a verage dust exposures were within current occupational standards, the risks of development of upper and lower respiratory symptoms and of specific sen sitization were clearly related to total dust and/or flour aeroallergen exp osure. The incidence of work-related chest symptoms in the presence of a po sitive skin test to flour or alpha -amylase in this setting was approximate ly 1 case per 100 py, (C) 2001 British Occupational Hygiene Society. Publis hed by Elsevier Science Ltd, All rights reserved.