Laryngeal cancer and occupational exposure to asbestos.

The risk of laryngeal cancer associated with occupational exposure to asbestos was evaluated by a review of published reports. In only two of 13 cohort studies was the standardized mortality ratio (SMR) significantly increased. Smoking (a risk factor for laryngeal cancer) may have been more prevalent among asbestos workers than among the comparison populations. This was not taken into account in any of the studies, and may have caused the SMRs to be overestimated. Two of eight case-control studies reported large odds ratios (greater than or equal to 13) for laryngeal cancer. Subsequent case-control studies did not confirm this higher risk; the odds ratios in these studies were 0.3 to 1.9. The conclusion of the review, based on data from 13 cohort and 8 case-control studies, is that neither case-control nor cohort studies have established an increased risk of laryngeal cancer for asbestos workers.