Describes the design and findings of a pooled re-analysis of epidemiological studies investigating carcinogenicity in workers exposed to wood dust. The analysis included a large number of studies whose results have not been fully explored due to limitations, mainly linked to small size, inherent in each study. By pooling these studies, the IARC analysis allowed a more powerful interpretation of previously published case-control studies of sino-nasal cancer and cohort studies of workers in wood-related industries. The result is the largest data set ever assembled to examine the relationship between exposure to wood dust and human cancer.
Although exposure to wood dust has long been associated with a very high excess of sino-nasal cancer, the IARC analysis aimed to answer several remaining questions concerning the possible excess risk of cancer at other sites, the level of wood dust exposure needed to cause cancer, the differences between exposure to dust from soft- and hardwood, and the reasons for the wide range of relative risks for sino-nasal cancer and the results observed for other cancers. A uniform exposure assessment strategy was applied in order to classify study subjects according to levels of exposure.
The opening chapters explain the methodology of the pooled re-analysis and provide a detailed description for each of the twelve case-control studies of sino-nasal cancer and five cohorts of workers in wood-related industries. In addition to the predicted excess of sino-nasal cancer, the analysis found an excess of nasopharyngeal cancer and lymphatic and haematopoietic cancer, particularly multiple myeloma. No evidence was found for an excess risk of deaths from lung cancer.