Childhood leukemia around French nuclear power plants--the Geocap study, 2002-2007.

The aim of this work is to study the risk of childhood acute leukemia (AL) around French nuclear power plants (NPPs). The nationwide Geocap case-control study included the 2,753 cases diagnosed in mainland France over 2002-2007 and 30,000 contemporaneous population controls. The last addresses were geocoded and located around the 19 NPPs. The study used distance to NPPs and a dose-based geographic zoning (DBGZ), based on the estimated dose to bone marrow related to NPP gaseous discharges. An odds ratio (OR) of 1.9 [1.0-3.3], based on 14 cases, was evidenced for children living within 5 km of NPPs compared to those living 20 km or further away, and a very similar association was observed in the concomitant incidence study (standardized incidence ratio (SIR)=1.9 [1.0-3.2]). These results were similar for all the 5-year-age groups. They persisted after stratification for several contextual characteristics of the municipalities of residence. Conversely, using the DBGZ resulted in OR and SIR close to one in all of the dose categories. There was no increase in AL incidence over 1990-2001 and over the entire 1990-2007 period. The results suggest a possible excess risk of AL in the close vicinity of French NPPs in 2002-2007. The absence of any association with the DBGZ may indicate that the association is not explained by NPP gaseous discharges. Overall, the findings call for investigation for potential risk factors related to the vicinity of NPP and collaborative analysis of multisite studies conducted in various countries.

Road traffic and childhood leukemia: the ESCALE study (SFCE).

BACKGROUND: Traffic is a source of environmental exposures, including benzene, which may be related to childhood leukemia. OBJECTIVES: A national registry-based case-control study [ESCALE (Etude Sur les Cancers et les Leucémies de l'Enfant, Study on Environmental and Genetic Risk Factors of Childhood Cancers and Leukemia)] carried out in France was used to assess the effect of exposure to road traffic exhaust fumes on the risk of childhood leukemia. METHODS: Over the study period, 2003-2004, 763 cases and 1,681 controls < 15 years old were included, and the controls were frequency matched with the cases on age and sex. The ESCALE data were collected by a standardized telephone interview of the mothers. Various indicators of exposure to traffic and pollution were determined using the geocoded addresses at the time of diagnosis for the cases and of interview for the controls. Indicators of the distance from, and density of, main roads and traffic nitrogen dioxide (NO(2)) concentrations derived from traffic emission data were used. Odds ratios (ORs) were estimated using unconditional regression models adjusted for potential confounders. RESULTS: Acute leukemia (AL) was significantly associated with estimates of traffic NO(2) concentration at the place of residence > 27.7 µg/m(3) compared with NO(2) concentration < 21.9 µg/m(3) [OR=1.2; confidence interval (CI), 1.0-1.5] and with the presence of a heavy-traffic road within 500 m compared with the absence of a heavy-traffic road in the same area (OR=2.0; 95% CI, 1.0-3.6). There was a significant association between AL and a high density of heavy-traffic roads within 500 m compared with the reference category with no heavy-traffic road within 500 m (OR=2.2; 95% CI, 1.1-4.2), with a significant positive linear trend of the association of AL with the total length of heavy-traffic road within 500 m. CONCLUSION: This study supports the hypothesis that living close to heavy-traffic roads may increase the risk of childhood leukemia.