Background: Although numerous studies have provided evidence of an association between ambient air pollution and acute cardiac morbidity, little is known regarding susceptibility factors.
Methods: We conducted a time-stratified case-crossover study in 9 Italian cities between 2001 and 2005 to estimate the short-term association between airborne particles with aerodynamic diameter <10 μm (PM10) and cardiac hospital admissions, and to identify susceptible groups. We estimated associations between daily PM10 and all cardiac diseases, acute coronary syndrome, arrhythmias and conduction disorders, and heart failure for 167,895 hospitalized subjects ≥65 years of age. Effect modification was assessed for age, sex, and a priori-defined hospital diagnoses (mainly cardiovascular and respiratory conditions) from the previous 2 years as susceptibility factors.
Results: The increased risk of cardiac admissions was 1.0% (95% confidence interval [CI] = 0.7% to 1.4%) per 10 μg/m3 PM10 at lag 0. The effect was slightly higher for heart failure (lag 0, 1.4% [0.7% to 2.0%]) and acute coronary syndrome (lag 0–1, 1.1% [0.4% to 1.9%]) than for arrhythmias (lag 0, 1.0% [0.2% to 1.8%]). Women were at higher risk of heart failure (2.0% [1.2% to 2.8%]; test for interaction, P = 0.022), whereas men were at higher risk of arrhythmias (1.9% [0.8% to 3.0%]; test for interaction, P = 0.020). Subjects aged 75–84 years were at higher risk of admissions for coronary events (2.6% [1.5% to 3.8%]; test for interaction, P = 0.001). None of the identified chronic conditions was a clear marker of susceptibility.
Conclusions: An important effect of PM10 on hospitalizations for cardiac diseases was found in Italian cities. Sex and older age were susceptibility factors.
From the aDepartment of Epidemiology, Regional Health Service, Lazio Region, via S. Costanza 53, Rome, Italy; bEpidemiology Services, Regional Environmental Protection Agency, Piedmont, via Sabaudia 164, Turin, Italy; cEpidemiology Unit, Local Health Authority, Corso Italia 19, Milan, Italy; dEpidemiological Observatory, Regional Health Authority, via Mario Vaccaio 5, Palermo, Italy; eCenter for Cancer Prevention, via Cosimo il Vecchio 2, Florence, Italy; fEpidemiology Observatory, Department of Public Health, Local Health Authority, via Gramsci 12 a, Bologna, Italy; gInstitute of Clinical Physiology, National Research Council, via Monteroni snc, Lecce, Italy; hDepartment of Environmental Medicine and Public Health University of Padua, via Giustiniani 2, Padua, Italy; and iDepartment of Biology, University of Pisa, via Luca Ghini 5, Pisa, Italy.
Supported by the Italian Ministry of Health, Centro Nazionale per la Prevenzione ed il Controllo delle Malattie “Inquinamento Atmosferico e Salute: Sorveglianza Epidemiologica ed Interventi di Prevenzione, EPIAIR” (Det. 24 del 21/12/2006) and the Programma Strategico finanziato dal Ministero del Lavoro, della Salute e delle Politiche Sociali, dal titolo—ISS: Impatto sanitario associato alla residenza in siti inquinati, in territori interessati da impianti di smaltimenti/incenerimento rifiuti ed alla esposizione ad inquinamento atmosferico in aree urbane—Convenzione n. 41 (Det. 24 del 08/08/2008). The authors reported no other financial interests related to this research.
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Correspondence: Francesco Forastiere, Department of Epidemiology, Regional Health Service, Lazio Region, Italy V. S. Costanza n 53, 00198 Rome, Italy. E-mail: firstname.lastname@example.org.
Received May 2, 2011
Accepted January 9, 2012