Using data from the Nurses' Health Study (NHS), researchers investigated possible links between rotating night shift work and all-cause, cardiovascular disease (CVD), and cancer mortality in a study of almost 75,000 registered US nurses. After analyzing the data of 22 years of follow-up time, the researchers found that working rotating night shifts for more than five years was associated with an increase in all-cause and CVD mortality. Mortality from all causes was 11 percent higher for women with 6-14 or 15 years of rotating night shift work, while CVD mortality appeared to be 19 percent and 23 percent higher for both the groups, respectively. There was no association between rotating shift work and any cancer mortality, except for 25 percent higher risk of lung cancer in those who did rotating shift work for 15 or more years.
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.