Air pollution and respiratory drug use in the city of Como, Italy

Study objective and setting: Particulate air pollution has a known negative effect on human respiratory health, often studied with hospital admissions, emergency room access, or mortality as health indicators. We evaluate respiratory drug dispensing data as health indicators for the effects of total suspended particles (TSP) air pollution in the city of Como (84,713 inhabitants). Design: Weekly count of individual patients with respiratory drug dispensed (Cases) and weekly dispensed daily defined doses (DDD) of drugs were modelled with weekly air mean concentrations of TSP using a Poisson regression model adjusted for long-term trends, seasonal variations, calendar variations due to holidays, and weather. Main result: Relative risks (RR) were expressed for a variation from 10th to 90th percentile of TSP (29-92 μg/m3). Weekly aggregation was used in consideration of the complexity of drug dispensing data and potential biases of daily aggregation. For weekly mean concentrations of TSP, RR=1.082 (95% Confidence level (CI) 1.002-1.169) for Cases and RR=1.137 (95% CI 1.044-1.238) for DDD. Conclusion: Our study concludes that both Cases and DDD of dispensed respiratory drugs could be useful for epidemiological surveillance of air pollutant health effects. Further investigation may routinely allow health and economics considerations, producing a stimulating new tool for health policy makers.