A study published in the American Journal of Preventive Medicine says that there can be an increase in cardiovascular disease and lung cancer mortality in nurses who are working in rotating night shifts. In fact, a World Health Organization report in 2007 says that night shift work can be considered a carcinogen because the circadian rhythm of the body has been altered.
In the journal, the researchers found out that women who are working on rotating night shifts for five or more years have increased risk for cardiovascular disease mortality and those who are working 15 or more years on rotating night shifts have an increased risk for lung cancer mortality. Hence, it can add to the existing evidence that rotating night shift can lead to poor health and decreased longevity.
Disruption of the circadian system and sleep patterns play a major role in maintaining a healthy heart and a cancer-free body. There are many studies that pertain to night shift as detrimental to the health because it enhances the growth and development of cancer.
The study included 75,000 nurses in the United States who were on rotating night shifts. Using the Nurse's Health Study (NHS), the researchers studied 22 years of follow up and they discovered that rotating night shifts for five years can lead to an over-all increase of cardiovascular disease mortality.
According to Eva S. Schernhammer, MD, DrPH, currently Associate Professor of Medicine, Harvard Medical School, and Associate Epidemiologist, Department of Medicine, Brigham and Women's Hospital, Boston, "This study is one of the largest prospective cohort studies worldwide with a high proportion of rotating night shift workers and long follow-up time. A single occupation (nursing) provides more internal validity than a range of different occupational groups, where the association between shift work and disease outcomes could be confounded by occupational differences."
"These results add to prior evidence of a potentially detrimental relation of rotating night shift work and health and longevity...To derive practical implications for shift workers and their health, the role of duration and intensity of rotating night shift work and the interplay of shift schedules with individual traits (e.g., chronotype) warrant further exploration," she added.