Dimich-Ward H, Lorenzi M, Teschke K, et al. Mortality and cancer incidence in a cohort of registered nurses from British Columbia, Canada. Am J Ind Med. 2007;50:892-900.
Historically, nurses have been exposed to many diseases and illnesses in the course of providing care. As medical and nursing knowledge has evolved, care has become modified to prevent unnecessary exposures and risk to healthcare providers. Those who provide care to trauma patients are often at the forefront of risk for contamination of blood and body fluids. In addition, all healthcare providers are considered to have some type of risk when caring for their patients. This study was designed to determine whether nurses had an increased risk of mortality and incidence of cancers, including leukemia and other malignancies (eg, breast, ovarian, kidney), in comparison with the British Columbia, Canada, population.
ABSTRACT
A retrospective cohort study of Canadian registered nurses (RNs) from British Columbia was undertaken to determine risks of mortality and cancer incidence. This research also sought to evaluate whether employment in a particular job category and duration of employment were associated with an increased risk of cancer incidence or mortality. Another objective of this research was to determine whether there was a dose-response relationship according to duration and intensity of estimated exposure to anesthetic gases, ionizing radiation, and antineoplastic drugs.
The population cohort studied comprised nurses who were members of the Canadian Registered Nurses Association between 1974 and 2000. The researchers reviewed data from 58,125 RNs that were linked to Canadian death and cancer registries. The majority of nurses (96.7%) in the cohort group were female. Analyses included standardized mortality (SMR) and incidence ratios (SIR) as well as relative risks for internal comparisons. The SMR results revealed that all causes of mortality for female RNs were low, at 0.61 (95% CI, 0.58-0.64). The only elevated incidence ratio for female RNs was for malignant melanoma (1.27; 95% CI, 1.10-1.46), meaning that it was determined that the nurses in this study were more likely to develop malignant melanoma by 27%.
REVIEW
This research discovered that these RNs had a lower mortality rate than the general public from a variety of health problems including cancer, myocardial infarctions, and strokes. The RNs in this study also had a 39% lower mortality rate than the general population for death from any cause and were also more likely to survive specific cancer types. In addition, when taken as a whole, the nurses were 9% less likely than the general population to be diagnosed with cancer.
The study also found that nurses were more likely to develop certain cancers based on their specialty and how long they had been employed in comparison with other nurses. The research showed that a subgroup of nurses who had worked in the healthcare industry for more than 15 years had an increased risk of developing melanoma and rectal cancer, and those who worked for more than 25 years in healthcare had a greater chance of breast and lung cancer than those nurses who had worked in the profession for less than 5 years.
COMMENTARY
Healthful lifestyles and a healthy worker effect could be suggested from the low standardized mortality scores for the female RN cohort in this study. However, it would be helpful to see data from replication studies in other countries. Overall, more research is needed in other healthcare professional populations as well to validate this conclusion.
It is also of interest to note that the length of employment as a nurse, in hospitals and in specific fields, was associated with some increased risks of cancer. When the time period of the study data is considered, it could be attributed to the evolving knowledge of medicine and nursing care as well as changing safety protocols. Again, more research should be done to determine whether these data reflect exposure of nurses to hazardous materials, for example, chemotherapy medications, etc.
Other findings showed that nurses who have worked in hospitals were at a greater risk for lung cancer, rectal cancer, and breast cancer than nurses who had never worked in a hospital. In addition, nurses in medical and surgical nursing were more likely to be diagnosed with lung cancer and breast cancer than those who had not worked in these specialties.