Cohort study of residents of a district with soil and groundwater industrial waste contamination

Abstract

INTRODUCTION: A neighbourhood of the city of Ferrara (Italy) was built over an area polluted with chlorinated organic compounds. A residential cohort study was performed to assess the health profile of the population living in the polluted area. METHODS: The residential history of 3475 subjects who had lived in the East quadrant neighbourhood in the period 1994-2010 was constructed. Mortality for the period 19942010 and cancer incidence for the years 1994-2007 were studied. Standardised mortality ratios (SMR) for 2632 subjects and standardised incidence ratios (SIR) for 2578 subjects who had lived for at least 5 years in the area under study were calculated. Indicators were calculated for males and females combined, using the population of Ferrara as reference population. RESULTS: The health profile of the population of the East quadrant neighbourhood, defined using mortality indicators for major groups of causes, is essentially similar to that of the city of Ferrara. Increased mortality rates for lung cancer (SMR 131, 90% CI 94-178) and incidence rates for some cancer sites, including liver (SIR 135, 90% CI 67-243) were observed, albeit on the basis of few cases and with wide confidence intervals. DISCUSSION: The likelihood of observing significant increases in risk is reduced by the sizes of the cohorts and the short follow-up period, but some findings nonetheless suggest that, as a precautionary measure, the cohort study should be continued in parallel with measures for the reclamation of the site and that this study should take the form of epidemiological surveillance.

Keywords

• cohort study
• mortality
• cancer incidence
• industrial waste