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

Abstract

Objectives: To estimate the incidence of specific IgE sensitization and allergic respiratory symptoms among UK bakery and flour mill workers; and to examine the roles of flour aeroallergen and total dust exposures in determining these outcomes.Methods: A cohort of 300 new employees, without previous occupational exposure to flour, were followed prospectively for a median (range) of 40 (1-91) months. Cases-defined as those developing work-related symptoms or a positive skin prick test to flour or a-amylase during follow up-were compared with controls, matched for duration of employment. Exposures to flour aeroallergen 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. Fewer employees developed positive skin prick tests to flour (2.2 cases per 100 py) or a-amylase (2.5 cases per 100 py). Positive skin tests to occupational allergens were more common among those with new work-related symptoms. There were clear relationships between the risks of developing work-related symptoms or a positive skin prick test and three categories of estimated exposure to total dust or flour aeroallergen. Atopic employees were more likely to develop a positive skin prick test-but not work-related symptoms. These findings were unaffected by age, sex or cigarette smoking. Conclusions: In this population, many work-related symptoms which develop after first employment in modern UK bakeries or flour mills were not accompanied by evidence of IgE sensitization to flour or a-amylase. Although average dust exposures were within current occupational standards, the risks of development of upper and lower respiratory symptoms and of specific sensitization were clearly related to total dust and/or flour aeroallergen exposure. The incidence of work-related chest symptoms in the presence of a positive skin test to flour or a-amylase in this setting was approximately 1 case per 100 py.

Assessment of exposure to wheat flour and the shape of its relationship with specific sensitization

“…Workers in the industrialized bakeries had a four times higher risk of becoming sensitized at the same exposure level as workers in the flour mills and a twice as high risk as workers in the bakery-ingredient industry. Therefore, the sector of industry may serve as a proxy for the kind of dust mixture to which workers are exposed, as well as for the local environment (eg, temperature, degree of use of ventilation devices) or may represent individual characteristics [other than age, gender, or cigarette smoking, such as atopy (17)], which contribute to the differences between industries. The difference in the prevalence in atopy between the industries seems to be a key explanatory variable.…”

Controversies in epidemiology of occupational asthma

“…This type of study has recently been successfully applied in cohorts of young apprentices [4][5][6][7][8][9][10]. Some case-referent studies have been carried out in the field of OA [11,12]. These studies are valuable in identifying and quantifying risk factors.…”

Microbial Allergy with Special Focus on Saudi Arabia

“…It was found that several sources are responsible for emission of these bioaerosols in air. These sources include natural sites such as soil, water, plants and animals and human as well as anthropogenic like agricultural practices, healthcare units and industrial operations (Cullinan et al, 2001). Bioaerosols contribute to about 5-34% of indoor air pollution (http://www.pollutionissues.com/Ho-Li/Indoor).…”