Reference

Cullinan P, Cook A, Gordon S, Nieuwenhuijsen MJ, Tee RD, Venables KM, McDonald JC, Newman Taylor AJ, Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees, Eur Respir J, 1999;13:1139-1143,

BOHRF Original Authors' Main Conclusions

The original authors' main conclusions are taken from Abstract, Results and Discussion. They are decided upon by the authors of the BOHRF occupational asthma guidelines and form part of the guidelines.

Case-referent analysis of newly employed laboratory animal workers. Cases comprised persons developing symptoms of laboratory animal allergy or a positive skin prick test to rat urinary allergens; each was matched with up to two asymptomatic referents. Subjects were assigned to categories of exposure based on measurements of airborne rat urinary allergens. Of the cases, 80% reported that their symptoms started within 2 years of employment. A gradient of increasing odd ratios (OR) for the development of any such symptom across exposure categories was found; for respiratory symptoms and skin test reactions the ORs for subjects in the highest exposure category were lower than those in intermediate categories. Atopy increased the OR of most outcomes, as did cigarette smoking, although there was no evidence of a relationship between smoking and the development of a specific skin test reaction. Allergen exposure was confirmed as the most important determinant of laboratory animal allergy. Increased risk among atopic subjects but no statistically significant interaction between atopic status and allergen exposure. The OR associated with allergen exposure were generally higher than those for atopic status.

The following comments are from the editors of the BOHRF occupational asthma guidelines and form part of the guidelines.

31% of subjects with new chest symptoms reported these without other symptoms, whereas 45% had eye/nose and 35% had skin symptom

BOHRF Associated Evidence Statements

The BOHRF occupational asthma guidelines state that this reference is associated with the following evidence statements

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The risk of sensitisation and occupational asthma is increased by higher exposures to many workplace agents.

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Atopy increases the risk of developing occupational asthma caused by exposure to many high molecular weight agents that induce the production of specific IgE antibodies.

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Occupational rhinitis and occupational asthma frequently occur as co-morbid conditions in IgE associated occupational asthma.

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Rhino-conjunctivitis is more likely to appear before the onset of IgE associated occupational asthma.

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Sensitisation and occupational asthma are most likely to develop in the first years of exposure for workers exposed to enzymes, complex platinum salts, isocyanates and laboratory animal allergens.