Cancer risks in the optical manufacturing industry.

A mortality odds ratio (MOR) study has been conducted to explore the cancer risks of exposures experienced in the production of optical lenses and metal spectacle frames. Male death certificates were obtained from a Massachusetts town where a large optical industry is located. Craftsmen, foremen, and operatives of non-optical industries, such as woollen textile workers and workers in the optical company with short-term or no exposure, were chosen as reference workers their incomes were similar to those of the exposed workers. Cardiovascular disease (total 714) is chosen as the reference disease to explore cancers (total 232). An excess risk of total cancers observed = 70, expected = 48) has formed among lens workers. The excess may be accounted for mainly by the excess risk of gastrointestinal cancers; the standardised MORs (sMOR) for medium and long-term exposure were 2.2 and 2.5. The excess was especially evident for colorectal cancers; the sMORs for medium and long-term exposures were 3.2 and 2.6. Excess risks of gastrointestinal cancers (sMOR = 2.9) and colorectal cancers (sMOR = 3.4) were found among metal frame workers with long-term (employed for more than 29 years) exposure, but the number of exposed cases was small (9 and 6 respectively). These results suggest that exposure to abrasives or cutting oil mists or both, possibly by ingestion, might increase the risk of gastrointestinal (especially colorectal) cancers among lens and metal spectacle frame manufacturers.