Mortality and cancer incidence in New Zealand pulp and paper mill workers

To evaluate mortality and cancer incidence in a cohort of workers employed in the New Zealand pulp and paper industry, and to identify the exposures responsible for any increased risk.

A total of 8456 workers employed for at least one year in three pulp and paper mills between 1978 and 1990 were followed up until 1992. The observed number of deaths and cancer cases was compared with expected numbers calculated using five-year age-specific rates for the New Zealand population.

Vital status was determined for 81% of the cohort, and for 93% of the total person-years at risk. Mortality from all causes (standardised mortality ratios (SMR) = 0.80, 95% confidence intervals [CI] 0.71-0.89; 314 deaths), and from all malignant neoplasms (SMR = 0.95, 95% CI 0.78-1.15, 103 deaths), was lower than expected. Mortality from lung cancer (SMR = 1.33, 95% CI 0.94-1.83, 37 deaths) was marginally increased.

No overall increase in mortality from cancer or other causes was observed in this cohort. A small increase in lung cancer risk is suggested, although this was not statistically significant. Numbers of cases were too small for detailed analyses of associations between disease and specific exposures.