Rotating night shift work deteriorates health in general, enhances the development of lung cancer and cardiovascular disease (CVD), and contributes to higher mortality, new research has confirmed.

Women working rotating night shifts for five or more years had a modest increase in all-cause and CVD mortality and those working 15 or more years of rotating night shift work had a modest increase in lung cancer mortality, the findings showed.

Rotating night shift was defined in the study as working at least three nights per month in addition to days or evenings in that month.

“These results add to prior evidence of a potentially detrimental relation of rotating night shift work and health and longevity,” said Eva Schernhammer, associate professor of medicine at Harvard Medical School.

Sleep and the circadian system play an important role in cardiovascular health and antitumor activity.

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”, she added.

For the study, the authors analysed 22 years of follow-up data from the Nurses’ Health Study (NHS) that included almost 75,000 registered US nurses.

Mortality from all causes appeared to be 11 percent higher for women with 6-14 or 15 years of rotating night shift work.

CVD mortality appeared to be 19 percent and 23 percent higher for those groups, respectively.

Those who worked rotating night shift work for 15 or more years had 25 percent higher risk of lung cancer mortality.

The study appeared in the American Journal of Preventive Medicine.