P.2.38 Occupational exposure and incidence of asthma based on prescription of drugs

Prescription of drugs for obstructive lung diseases (ATC code R03) has previously been shown to be an indicator of actual asthma. In this cohort study, we have combined occupational information with data from redeemed prescriptions between 2000 and 2013 extracted from the National Danish Prescription register. In 2003 a total of 7255 persons aged 20 and 44 years fulfilled a questionnaire, which among other things, included information on their longest held job. The jobs of 6470 were coded according to ISCO-88 and an asthma Job Exposure Matrix (JEM) was applied. Prevalent asthma was defined as at least two redeemed prescriptions of a R03 drug within 2 years. Incident asthma between 2003 and 2013 was defined as not having redeemed a R03 prescription in the previous years. Data was analyzed separately for each gender using multivariate logistic regression and presented as odds ratios (OR) with 95% confidence intervals (CI). Among those having a job 327 (5.1%) were identified as incident cases and 467 (7.2%) as prevalent cases. In females increased incidences were seen in exposures to reactive low molecular weight (LMW) substances (OR1.47 (95% CI 1.04–2.07)), cleaning agents (OR 1.52 (1.05–2.18)), metals (OR 3.31 (1.63–6.64)), while increased prevalence was seen with mite exposure (OR 4.41 (1.74–11.2)) and irritant gases (OR 1.76 (1.16–2.69)). In males no increased incidences were seen and only an increased prevalence with mixed environments (OR 2.24 (1.13–4.43)).In jobs increased prevalence and incidence were seen in female cleaners and drivers. Increased prevalence was seen in male printing workers. Meaningful associations with well-known asthmagenic exposures in young adults with asthma can be identified in administrative register data, and implementing the analyses of register data from larger populations will have the power to detect potential increased risks due to rare exposures or changes in risk over time.