Cancer incidence and mortality among Swedish leather tanners.

OBJECTIVES The aim was to study the incidence of cancer among Swedish leather tanners. METHODS A cohort of 2026 subjects who had been employed for at least one year between 1900 and 1989 in three Swedish leather tanneries, was established. The cancer incidence and mortality patterns were assessed for the periods 1958-89 and 1952-89 respectively, and cause-specific standardised incidence and mortality ratios (SIRs and SMRs) were calculated. RESULTS A significantly increased incidence of soft tissue sarcomas (SIR 4.27, 95% confidence interval (95% CI) 1.39-9.97) was found, based on five cases. Excesses, (not statistically significant) was also found for multiple myelomas (SIR 2.54, 95% CI 0.93-5.53), and sinonasal cancer (SIR 3.77, 95% CI 0.46-13.6). CONCLUSIONS The increased incidence of soft tissue sarcomas adds support to previous findings of an excess mortality in this diagnosis among leather tanners. A plausible cause is exposure to chlorophenols, which had occurred in all three plants. The excess of multiple myelomas may also be associated with exposure to chlorophenol. The association between incidence of cancer and specific chemical exposure will be elucidated in a cohort-based case-referent study.