Abstract

Background
Workers exposed to laboratory animals have a high risk of developing laboratory animal allergy (LAA). Atopy seems to be the main risk factor for LAA. We hypothesized that occupational sensitization is a better predictor for the development of asthma, rhinitis, and bronchial hyperresponsiveness (BHR) than common sensitization.
Objective
To investigate the association between occupational sensitization to laboratory animals and clinical outcomes.
Methods
This was a cross-sectional study performed at two universities on students and employees dealing with small rodents. The subjects were allocated in groups: non-sensitized, common sensitization, or occupational sensitization, according to the results of the skin prick test (SPT). All subjects answered a questionnaire about animal exposures, symptoms, allergic diseases, and underwent spirometry and bronchial challenge test with mannitol. Multivariate analysis was performed using Poisson regression to estimate the prevalence ratio (PR).
Results
Data from 453 volunteers were analysed. Non-sensitized group comprised 237 subjects; common sensitization group, 142 subjects; and occupational sensitization group, 74 subjects. Occupational sensitization was associated with greater risk for all outcomes studied. When the common sensitization group was reference, skin symptoms had PR of 1.36, 95% confidence interval (CI): 1.01-1.85; wheezing had PR of 1.75, CI 95%: 1.21-2.53; rhinitis had PR of 1.25, 95%: 1.11-1.40; nocturnal dyspnoea had PR of 2.40, 95% CI: 1.31-4.40; bronchial hyperresponsiveness (BHR) had PR of 2.47, 95% CI: 1.50-4.09; and confirmed asthma had PR of 2.65, 95% CI: 1.45-4.85. In addition, the overlap of asthma, rhinitis, and skin symptoms in a same subject was significantly more prevalent in the occupational sensitization group, 16.2% versus 4.9% in the common sensitization group.

Conclusion and Clinical Relevance
Occupational sensitization is associated with allergic symptoms and respiratory diseases. SPT with occupational allergens along with other parameters may contribute to detection of risk for allergic and respiratory diseases associated with exposure to laboratory animals.

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