Mortality and hospitalization associated to emissions of a coal power plant : a population-based cohort study

Background Coal-fired thermal power plants represent a significant source of air pollutants, especially sulfur dioxide (SO2) that has been associated with an increased risk of mortality and morbidity for respiratory and cardiovascular disease. A coal power plant in Vado Ligure (Italy) (CPPVL) started in 1970 was stopped in 2014 by the Prosecutor's Office on the grounds of environmental and health culpable disaster. Objective To investigate the association between the exposure of residents to atmospheric pollutants emitted by CPPVL and the risk of mortality and hospitalization, considering both cancer and non-cancer causes in a population-based cohort study. Methods SO2 and nitrogen oxides (NOx), estimated using the ABLE-MOLOCH-ADMS-Urban dispersion model, were selected as representative surrogates of exposure to CPPVL emissions (SO2-CPPVL) and cumulative emissions from other sources of pollution (NOx-MS), respectively. The relationship between each health outcome and categories of exposure to SO2-CPPVL was estimated by the Hazard Ratio (HR) using multiple sex-specific Cox regression models, adjusted for age, exposure to NOx-MS, and socio-economic deprivation index using SO2-CPPVL first quartile as a reference. Results 144,019 individuals were recruited (follow-up 2001-2013). An excess of mortality was found for all natural causes (men: 1.49; 95% CI 1.38-1.60; women: 1.49; 95% CI 1.39-1.59), diseases of the circulatory system (men: 1.41; 95% CI 1.24-1.56; women: 1.59; 95% CI 1.44-1.77), of the respiratory system (men: 1.90; 95% CI 1.47-2.45; women: 1.62; 95% CI 1.25-2.09), and of the nervous system and sense organs (men: 1.34; 95% CI 0.97-1.86; women: 1.38; 95% CI 1.03-1.83), and in men for trachea, bronchus, and lung cancers (1.59; 95% CI 1.26-2.00). Results of hospitalization analysis were consistent with those of mortality. Conclusion Results obtained, also when considering multiple sources of exposure, indicate that exposure to CPP emissions represents a risk factor for selected health outcomes as well as the urgently adoption of primary prevention measures and of a specific surveillance programme.