Mortality pattern among biological research laboratory workers.

A cohort study was conducted to investigate the mortality of individuals employed by biological research institutes in the UK. The inclusion criteria were met by 12,703 individuals, of whom 95% were traced (11,502 alive, 395 deaths, 246 embarkations). All-cause mortality was significantly reduced in men (standardised) mortality ratio (SMR) 55 and women (SMR 52). Mortality was also significantly reduced for circulatory and respiratory diseases, and overall there was low mortality from malignant neoplasms. SMRs exceeded 100, but were not statistically significant, for infective and parasitic diseases. There were no statistically significant raised SMRs for any cancer site. Workers were categorised as ever worked in a laboratory (laboratory workers) and never worked in a laboratory (non-laboratory workers). The all-cause SMR was significantly reduced in both groups, as was mortality from circulatory and respiratory diseases. The SMR for malignant neoplams was also significantly reduced in laboratory workers. On the basis of follow-up to 31 December 1994, there is no evidence of any overall increased risk of mortality in biological research laboratory workers. However, the power of the analysis is limited by the young age of many cohort members and short duration of follow-up. Follow-up is continuing and the data will be reanalysed once more deaths have accumulated.