Pooled reanalysis of cancer mortality among five cohorts of workers in wood-related industries

Abstract

Objectives To provide more information regarding the risk of cancer associated with wood dust, a pooled reanalysis of data form five cohort studies was performed. Methods The combined cohort consisted of 28 704 persons from five studies: British furniture workers, members of the union representing furniture workers in the United States, two cohorts of plywood workers, and one of wood model markers, among whom 7665 deaths occurred. Pooled analyses were carried out for all of the cohorts combined, the two furniture worker cohorts combined, and the two plywood workers cohorts combined. Results Significant excesses of nasal [observed 11 standardized mortality ratio (SMR) 3.1, 95% confidence interval (95% CI) 1.6--5.6] and nasopharyngeal (observed 9, SMR 2.4, 95% CI 1.1--4.5) cancer were observed. That for nasal cancer appeared to be associated with exposure to wood dust but was based solely on cases form the British furniture worker cohort, while that of nasopharyngeal cancer was observed for furniture and plywood workers and was associated with both high and low probability of wood dust exposure. Some support for an excess risk of multiple myeloma was also observed but was less clearly associated with wood dust exposure. No excesses of lung, larynx, stomach, or colon cancer were found to be associated with any surrogate indicators of wood dust exposure. Conclusion Workers exposed to wood dust may have an excess risk of nasopharyngeal cancer and multiple myeloma in addition to sinonasal cancer. The limitations of this study would tend to obscure relationships, rather than create false positive findings.