The effects of air pollution on hospital admissions for cardiac, cerebrovascular and respiratory diseases in the multi-city Italian EPIAIR2 study

Background. In Italy the EPIAIR multi-centric surveillance study has already investigated short-term effects of air pollution on cardiovascular and respiratory diseases on hospital admissions from 2001 until 2005 in 10 cities. Aim. To evaluate the impact of different exposures of air pollutants on cause-specific hospital admissions in a larger number of cities (25) and in an extended period (until 2010). Methods. Daily counts of hospital admissions of people (all ages and <14 years) resident and hospitalized in each city were analyzed in the period 2003-2010. A time-series analysis using an over-dispersed Poisson regression model was performed to explore the effects of PM2.5 and PM10 on cardiac, cerebrovascular and respiratory emergency hospitalizations. The single pollutant model was adjusted for time trend, seasonality, and potential confounders. Immediate (lag 0, lag 0-1), delayed (lag 2-5), and prolonged (lag 0-5) effects were evaluated. City-specific results were then combined in a random effects meta-analysis. Results. We found significant increases in cardiac and respiratory hospitalizations for 10µg/m3 increase for PM10 (0.41% lag 0, 95%CI:0.07-0.75 and 0.66% lag 0-5, 95%CI:0.09-1.22, respectively). The same increase in PM2.5 was strongly associated with respiratory diseases (1.30% lag 0-5, 95%CI:0.68-7.93. PM10 and PM2.5 had higher effects on respiratory diseases of children (1.70% lag 0-5, 95%CI:-0.68-4.14, and 3.47% lag 0-5, 95%CI:0.05-7.02, respectively) and at longer lags of exposure. No significant effect was found on cerebrovascular diseases. Heterogeneity between city-specific estimates was negligible, except for respiratory hospitalizations of children. Conclusions. Our results confirm on a wider number of Italian cities the harmful short-term effect of air pollution on morbidity. Specifically, we found strong effects of PM10 and PM2.5 on cardiopulmonary hospitalizations of all-aged people as well as respiratory diseases in children.