Aeroallergens and work-related respiratory symptoms among office workers

We sought to determine the association between office workers' respiratory tract symptoms and immediate skin test reactions with exposure to fungal and house dust mite aeroallergens at their work sites.

An initial prevalence survey was conducted among 1102 full-time workers in six mechanically ventilated, air-conditioned, nonindustrial buildings in downtown Montreal. Detailed environmental measures of 214 subjects' work sites were determined. Half of the workers reported frequent work-related respiratory tract symptoms on the initial survey. Participants simultaneously underwent allergy skin prick testing and completed a second self-administered questionnaire.

Contaminant levels were low and not associated with symptoms in the great majority of workers. For approximately 17% of workers, symptoms were associated with exposure to total concentrations of house dust mite allergen greater than 1 microg/gm floor dust (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.3, 19.5]) or to detectable airborne Alternaria allergens in their offices (OR, 3.3; 95% CI, 1.2, 9.4 and in the ventilation system supplying their offices (OR, 3.9; 95% CI, 1.6, 9.6). Workers with positive skin test reactions to Alternaria extract were exposed at their work site to airborne Alternaria allergen (OR, 4.4; 95% CI, 1.4, 14.5) and cited significantly more respiratory symptoms on both questionnaires. Detection of airborne Alternaria allergen at work sites was significantly associated with detection in the ventilation system (OR, 4.0; 95% CI, 1.4,10.9); this was in turn associated with lower efficiency filters.

Potentially avoidable exposure to aeroallergens accounted for symptoms in a small subgroup of office workers with frequent work-related respiratory tract symptoms.