By Robert Preidt
MONDAY, Jan. 5, 2015 (HealthDay News) -- Working rotating night shifts may pose a threat to your health, a new study suggests.
The study defined rotating shift work as at least three nights spent working each month, in addition to days and evenings worked in the month.
In the new study, researchers led by Dr. Eva Schernhammer of Harvard Medical School tracked 22 years of data from about 75,000 nurses across the United States.
While the study couldn't prove cause-and-effect, it found that people who worked rotating night shifts for more than five years had an 11 percent increased risk of death from all causes.
The risk of death from heart disease was 19 percent higher among those who worked such shifts for six to 14 years, and 23 percent higher for those who worked such shifts for 15 or more years, Schernhammer's group found.
Nurses who worked rotating night shifts for 15 or more years also had a 25 percent higher risk of death from lung cancer, according to the study.
The findings are to be published in the March issue of the American Journal of Preventive Medicine.
"These results add to prior evidence of a potentially detrimental relation of rotating night shift work and health and longevity," Schernhammer, an associate professor of medicine at Harvard and associate epidemiologist at Brigham and Women's Hospital in Boston, said in a journal news release.
Further research is needed to learn how individual traits might interact with rotating night shift work to harm health, she added.