Non-Hodgkin's Lymphomas Mortality in 25 Italian Municipalities With Solid Waste Incinerators (1981–2001)

Abstract

ISEE-576 Objective: Recently epidemiological studies suggested an increased risk of Non-Hodgkin's Lymphomas (NHLs) among population residing near solid waste incinerators (SWIs) (Viel 2003, Floret 2003, Biggeri 2005). An ecological study on NHLs mortality in 25 municipalities with SWIs was conducted to test hypothesis of an association by using a large sample size of active incinerators in Italy. Materials and Methods: NHLs mortality was investigated during 4 periods (1981–1985, 1986–1991, 1992–1996, 1997–2001) in 25 municipalities, according to the SWI time of activity and the NHL latency period (15 yr time frame to be conservative). A total of 1,830 NHL-related deaths (949 males and 881 females) was observed in the overall period (1981–2001). For each municipality the SMR adjusted for age was obtained. To calculate expected mortality, municipalities were included inside a 30 km radius circle. A pooled estimation of the SMR obtained by meta-analysis was performed for the 25 municipalities. A multiple metaregression model was used to analyze the study, activity, and latency periods, the incinerator burning capacity, the number of resident, the residence density, and the deprivation index. Results: The pooled estimation of the SMR resulted 1.08 (CI 95%: 1.01–1.11) in males and 0.96 (CI 95%: 0.90–1.03) in females. The multiple metaregression model showed the incinerator burning capacity and the latency period to be statistically significant factors (P<0.05). Of the 4 latency periods considered, the 15–20 and 20–25 periods showed statistically significant excesses of NHL mortality in men (SMR=1.10; CI 95%: 1.00–1.21). Municipalities having SWIs with a burning capacity of <50,000 ton/yr showed a higher mortality excess for men (SMR=1.14; CI 95%: 1.00–1.21) compared to municipalities with SWIs >50,000 ton/yr (SMR=1.04; CI 95%: 0.95–1.13). Conclusions: Empirical evidence of NHL mortality excess in men and differences related to the latency periods and to the SWI capacities need to be further investigated.