Last Updated: 2008-01-07 16:43:44 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Nurses have a lower risk of dying from several different conditions compared with individuals in the general population, according to the findings of a large Canadian study of registered nurses (RNs).

However, the researchers also found that the risk of melanoma, the most deadly type of skin cancer, climbed with the number of years a nurse spent in her profession.

A subgroup of nurses who worked in hospitals or medical-surgical specialties had an increased risk of lung cancer.

The increased risk with longer-term work could be related to occupational exposures to carcinogens, such as radiation and certain drugs, while disruption of circadian rhythms due to shift work could also be a factor, Dr. Helen Dimich-Ward of the University of British Columbia in Vancouver and her colleagues suggest.

The researchers reviewed mortality data for the 58,125 RNs working in British Columbia from 1974 to 2000, most of whom were women. Because the number of male RNs was too small to produce statistically valuable data, the researchers didn’t include them in their analysis.

Overall, the researchers found that the RNs were 39% less likely to die during the course of the study than individuals in the general population. They also had a lower risk of death from a number of specific causes, including heart disease, stroke and cancer in general.

The subgroup of nurses who had been on the job for at least 15 years had a significantly increased risk of malignant melanoma and rectal cancer. Those who had been in the profession for 25 years or longer had an increased risk of breast and lung cancer compared with those who had been working in nursing for less than 5 years.

"Further investigations are needed to determine whether increased cancer risk among female RNs can be attributed to occupational exposures," the researchers conclude.

Am J Ind Med 2007;50.