Association between PM10 and mortality at municipalities’ level in Slovenia: ecological spatial study (LIFE MED HISS LIFE12 ENV/IT/000834)

Introduction Several ecological spatial studies have demonstrated an association between high outdoor PM10 levels and mortality. In Slovenia, several polluted areas exist, with specific geographical and meteorological conditions. Consequently, the aim of this study was to assess the spatial association between PM10 in outdoor air and mortality at municipality level in the entire country. Methods This study used an ecological spatial design and was conducted as a part of Life MED HISS European project. The unit of observation were 210 municipalities in Slovenia. Mortality data were obtained for the period 2010 to 2014 and environmental data for year 2011. The association were investigated using Poisson regression models without and with spatial random effects. The observed health outcome in the analysis was mortality due to following diagnoses according to the World Health Organization (ICD-10): natural causes, neoplasm, lung cancer, cardiovascular and respiratory diseases. The modelled yearly average of PM10 concentrations at municipality level was included in the analysis as explanatory factor. Data on potential confounding factors included the percent of participants with low education level, obesity, physical inactivity, alcohol consumption, present and ever smoking, passive smoking, active population, and average monthly earnings. Results PM10 was significantly associated with mortality for natural causes in all year studied except 2014, e.g. the relative risk (RR) and 95% credibility intervals (CI) for 2011 were (1.011; 1.004 to 1.019) for each 1ug/m3 increase in PM10. Associations were also found for mortality due to cancer and cardiovascular and respiratory diseases. Conclusion High PM10 levels were associated to higher mortality rates at the municipalities in Slovenia. Future work should consider smaller areas and the use of multipollutant models.