Mortality and cancer incidence in a cohort of registered nurses from British Columbia, Canada

BACKGROUND: A retrospective cohort study of provincial registered nurses (RNs) from British Columbia, Canada was undertaken to determine risks of mortality and cancer incidence; in particular for breast cancer and leukemia. METHODS: Cohort records of RNs from 1974 to 2000 were linked to Canadian death and cancer registries. Analyses included standardized mortality (SMR) and incidence ratios (SIR) as well as relative risks for internal comparisons. RESULTS: There were 58,125 RNs in the cohort (96.7% females). The SMR for all causes of mortality for female RNs was low, at 0.61 (95% CI, 0.58-0.64). The only elevated SIR for female RNs was for malignant melanoma (1.27; 95% CI, 1.10-1.46). Ever working in a hospital, medical surgical specialties or maternal/pediatrics showed some elevated cancer risks. CONCLUSIONS: Low SMRs for the female RN cohort suggest healthful lifestyles and a healthy worker effect. Length of employment as a nurse, in hospitals and in specific fields was associated with some increased risks of cancer.