Background: the body of evidence on health effects of residential exposure to urban waste incinerators suggests association with reproductive outcomes and some cancers, but the overall evidence is still limited.
Objectives: we evaluated the impact of two incinerators on hospital admissions for respiratory and cardiovascular diseases in a cohort of people living nearby two incineration plants in Lazio Region (Central Italy) using a before-and-after design.
Methods: the study area was defined as the 7-km radius around the incinerators. People who were resident in the area from 1996 to 2008 were enrolled in a retrospective longitudinal study. All addresses were geocoded. A Lagrangian dispersion model (SPRAY) for PM₁₀ (ng/m³) was used for incinerators exposure assessment. Average annual concentration of background PM₁₀ (μg/m³) was estimated on a regional basis by means of RAMS and FARM models. Both PM₁₀ exposures were estimated at the residential address. All subjects were followed for hospital admissions in the period before (1996-2002) and after (2003-2008) the activation of the plants. The association between exposure to emissions from incinerators and hospitalizations in the two periods was estimated using the multivariate Cox model (for repeated events), adjusting for age, area-level socioeconomic status, distance from industries, traffic roads and highways. An interaction term between the period of follow-up (before or after the activation of the plants) and the exposure levels was used to test the effect of the incinerators.
Results: 47,192 subjects resident in the study area were enrolled. No clear association between pollution exposure from incinerators and cause-specific morbidity of residents in highest concentration areas was found when compared to the reference group. However, an effect of PM₁₀ on respiratory diseases and chronic obstructive pulmonary disease was suggested. The effect was due to excesses of hospitalizations for the same causes among men living in highest exposure areas in respect to the reference group (hazard ratio - HR: 1.26; 95%CI 0.99-1.60, and HR: 1.86; 95%CI 1.04-3.33, respectively). There were associations between exposure to background pollution from other sources and hospitalizations for diseases of the circulatory system (HR: 1.08; 95%CI 1.03-1.13) and respiratory diseases (HR: 1.07; 95%CI 1.02-1.11) (for a unitary increment of PM₁₀, μg/m³).
Conclusions: living in areas with high PM₁₀ levels due to incinerators was associated with increased morbidity levels for respiratory disorders among men. The study area is critical from an environmental point of view, hence an epidemiological surveillance is recommended.