Morbidity and mortality of people who live close to municipal waste landfills: a multisite cohort study

BACKGROUND The evidence on the health effects related to residing close to landfills is controversial. Nine landfills for municipal waste have been operating in the Lazio region (Central Italy) for several decades. We evaluated the potential health effects associated with contamination from landfills using the estimated concentration of hydrogen sulphide (H2S) as exposure. METHODS A cohort of residents within 5 km of landfills was enrolled (subjects resident on 1 January 1996 and those who subsequently moved into the areas until 2008) and followed for mortality and hospitalizations until 31 December 2012. Assessment of exposure to the landfill (H2S as a tracer) was performed for each subject at enrolment, using a Lagrangian dispersion model. Information on several confounders was available (gender, age, socioeconomic position, outdoor PM10 concentration, and distance from busy roads and industries). Cox regression analysis was performed [Hazard Ratios (HRs), 95% confidence intervals (CIs)]. RESULTS The cohort included 242 409 individuals. H2S exposure was associated with mortality from lung cancer and respiratory diseases (e.g. HR for increment of 1 ng/m(3) H2S: 1.10, 95% CI 1.02-1.19; HR 1.09, 95% CI 1.00-1.19, respectively). There were also associations between H2S and hospitalization for respiratory diseases (HR = 1.02, 95% CI 1.00-1.03), especially acute respiratory infections among children (0-14 years) (HR = 1.06, 95% CI 1.02-1.11). CONCLUSIONS Exposure to H2S, a tracer of airborne contamination from landfills, was associated with lung cancer mortality as well as with mortality and morbidity for respiratory diseases. The link with respiratory disease is plausible and coherent with previous studies, whereas the association with lung cancer deserves confirmation.