An extensive epidemiological investigation of a kidney cancer cluster in a chemical plant: what have we learned?

OBJECTIVES: In 2003, a cluster of renal cell carcinoma (RCC) cases was reported among men working at a French chemical plant using a proprietary process to produce vitamin A. The 10 index cases yielded a standardised incidence ratio of 13.1 for 1994-2002. Nine of these 10 cases were diagnosed by a plant-specific abdominal ultrasonography screening programme that targeted exposure to an intermediate chemical, 4-chloro-1,1-dimethoxy-3-methyl-2-butene, commonly named 'chloracetal C5', suspected as the cause by some experts. Epidemiological investigations sought to examine the relations between occupational exposures and RCC. METHODS: A retrospective cohort mortality study and a nested case--control study were conducted. The cohort study included all workers who had been employed at the plant for at least 6 months between 1960 and 2003. The case--control study included an extensive search within the region for other kidney cancer cases among the cohort members. Industrial hygienists assessed occupational exposure. RESULTS: From 1968 to 2006, no significant excess mortality was observed for all causes of death or for all cancers. We found excess mortality for kidney cancer only among women. The nested case--control study showed a dose--response relation for cumulative exposure to chloracetal C5: the OR rose from 2.5 in the low-exposure category to 10.5 in the high-exposure group. Adjustment for screening attenuated this relation. CONCLUSIONS: The results of the case--control study were consistent with the positive results of in vivo genotoxic tests and suggest that chloracetal C5 can have a causal role in RCC.

Development of a French epidemiological surveillance system of workers producing or handling engineered nanomaterials in the workplace.

OBJECTIVE: Concern has been raised about the potential impact of nanomaterials exposure on human health, and France has decided to implement a timely epidemiological surveillance tool of workers likely to be exposed to engineered nanomaterials that could accompany the development of nanotechnologies. METHODS: A comprehensive review of the toxicological and epidemiological literature has been conducted together with an exploratory study among French companies producing or handling nanoobjects. RESULTS: A double surveillance system is proposed consisting of a prospective cohort survey and repeated cross-sectional studies. The aim of the cohort is (1) to monitor long-term health effects and (2) to allow of further research. Setting-up an exposure registry is the first planned step. CONCLUSIONS: The protocol is about to be submitted to the French Government for approval and funding.