Associations between long-term exposure to air pollution and cause-specific mortality in River Sacco Valley area

BACKGROUND AND AIM: The River Sacco Valley is an industrial contaminated site in a central area of Italy. It is characterized by environmental pollution and socioeconomic deprivation. The study aim is to evaluate the chronic effects on cause-specific mortality of air pollution and socioeconomic deprivation (SEP) in an administrative cohort of residents in an industrial polluted site. METHODS: Subjects who were resident in River Sacco Valley between 2008 and 2018 were enrolled by linking administrative data. We collected information about age, sex, residential address and cause of death. Exposure to PM10, PM2.5, NO2, SO2, Benzene and O3 were assessed by FARM models for each residential address, while socioeconomic deprivation has been derived by an area-level indicator. Cox proportional hazard models adjusted by age (as time-scale), sex and city of residence were used to evaluate the effects of exposure to air pollutants and SEP to natural, cardiovascular, respiratory and malignancies mortality. RESULTS: 182578 subjects were enrolled in the cohort, among which 30% were aged 50+ years and 35% had high SEP. We observed 9205, 4019, 573, 2790 non-accidental, cardiovascular, respiratory and malignant cancer deaths, respectively. Each pollutant had average levels above the WHO guidelines standards. The results of main analysis showed positive hazard ratios (HR) per IQR increases up to 1.084 (95% confidence intervals: 0.99, 1.18) and 1.136 (0.99, 1.30) for PM10 and non-accidental and cardiovascular mortality, respectively. Furthermore, high deprivation was associated positively with each outcome. In particular, we registered HRs equals to 1.064 (0.98, 1.16) and 1.101 (0.97, 1.25) for non-accidental and cardiovascular mortality in high vs low SEP category. CONCLUSIONS: Living in a polluted site worse the health status for several causes. We observe that high levels of air pollutants and socioeconomic deprivation are linked to excess of risk of cause-specific mortality in the River Sacco Valley area.