It is not likely that bias with respect to ascertainment and coding of the causes of death may have affected the study outcome. Information regarding the causes of death was collected from the CBS where the causes of death were coded at the time of death by trained nosologists who were unaware of our study PS-341 manufacturer and were unaware of which persons were or were not a member of the cohort. Equally, information regarding exposure,

including the calculation of total intake, was performed without any knowledge of the vital status and cause of death if applicable. Also, the number of subjects lost to follow-up in this study is low when considering the long period of follow up. This follow up has even been able to trace

some of the respondents, which were lost-to-follow up in previous updates, due to remigration and improvements in the registries. A limitation of the study is its relatively small sample size. However, the power of a retrospective cohort study depends on the number of expected events of interest, in this case cancer deaths, in combination with the expected magnitude of the effect of the exposure. In fact, given an α level of 0.05 and 80% power, the sample size (i.e. person years) of this study is capable of detecting at least a 34% increase risk in cancer (Armstrong 1987), if such buy FG-4592 a risk did exist. However, as none of the cancers Aldol condensation revealed a significant excess mortality risk and no exposure response relationship was observed for any of the cancer sites, this follow up study supports the conclusion that aldrin/dieldrin exposure does not lead to an increased cancer risk in man. This cohort is one of two cohorts that have been involved in the production of dieldrin and aldrin in the world. Their exposure has been accurately documented and as such provides an excellent opportunity to learn more about the possible long-term effects of these pesticides. In addition, the time window of observation is 52 years, between 1 January 1954 and 30 April

2006, which is a sufficient latency period. In fact, all exposed workers were employed this website before 1 January 1970 and 52.3% before 1 January 1960. Our findings add to the growing body of evidence, provided by both epidemiological studies (Amoateng-Adjepong et al. 1995; Ward et al. 2000) and recent animal studies (Stevenson et al. 1999; Kamendulis et al. 2001), showing a lack of an association between aldrin/dieldrin exposure and cancer mortality. The overall mortality of this occupational cohort remains significantly lower than the general male population of the Netherlands, after 52 years of follow-up. This is commonly referred to as the healthy worker effect (Checkoway et al. 1989), which can be attributed to a number of factors (Li and Sung 1999).