Lung function decline in laboratory animal workers: the role of sensitisation and exposure.

BACKGROUND Little is known about the relation between allergic sensitisation and subsequent long term lung function changes in working populations exposed to sensitising agents. AIMS To investigate whether exposure and work related sensitisation to laboratory animals are associated with lung function decline. METHODS The relation between exposure and sensitisation to laboratory animal allergens and changes in lung function was investigated in a longitudinal study (median follow up 2.0 years) among 319 laboratory animal workers. Subjects who had been working with laboratory animals for less than 4 years (n = 102) were analysed separately, since an earlier cross sectional analysis had suggested a strong healthy worker effect in more experienced workers. RESULTS In multiple regression analyses both sensitisation and exposure appeared to contribute independently to lung function decline in subjects who had been working with laboratory animals for less than 4 years, adjusting for gender, age, smoking, and atopy. Lung function decline was most pronounced in sensitised subjects who continued to be in contact with the animals to which they were sensitised, with estimated average excess declines in FEV1, FVC, and MMEF of 83 ml/y (p < 0.05), 148 ml/y (p < 0.01), and 7 ml/s/y (p = 0.9). CONCLUSIONS We conclude that exposure to laboratory animals is a significant risk factor for accelerated lung function decline, and that sensitised workers are especially at risk.