Risk of miscarriage in women exposed to the emissions of a modern municipal solid waste incinerator

Introduction. There is an increasing trend towards using incineration to solve the problem of waste management, raising concern about its potential health impact. We implemented asurveillance program on reproductive health of the population of an Italian city (population around 180,000) where a modern incinerator has been operating for the past few years. This currentstudy focuses on miscarriage risk in women living in proximity to this plant.Methods. We conducted a prospective study among two dynamic cohorts of women aged 16-49 residing in three distinct areas according to predicted fall-out of the incinerator pollutants(area A, with the highest exposure; area B, with intermediate exposure; area C, corresponding to the remaining municipal territory, considered as ‘unexposed’). We also followed two cohorts of female employees aged 16-49, working in the A and B areas, though occupational information for these women was available only for 2003. During the 2003-04 period, we identified all cases of spontaneous abortion occurring in these cohorts through the regional hospital discharge database, and we calculated the age-standardized morbidity ratio (SMR) of miscarriage in the ‘exposed’ cohorts, using rates in the whole municipal population as reference incidence.Results. In the residential cohorts, we detected 14 spontaneous abortions (7 in 2003 and 7 in 2004) among 1979.3 person-years of follow-up. In the occupational cohorts encompassing atotal of 189.4 person-years, we did not observe any cases of miscarriage. We did not detect an excess risk of spontaneousabortion in women residing or working in proximity to the waste incinerator in either of the exposure areas. SMR of miscarriage were lower in the area with the highest exposure compared with the intermediate exposure area.Data about socioeconomic status abstracted from the General Registry Office were substantially similar for the three residential cohorts.Discussion and conclusions. These results do not suggest that exposure to the emissions of a modern municipal waste incinerator is associated with increased risk of miscarriage, though the limited statistical stability of the point estimates suggests caution in the evaluation of the study findings.