Study links rotating night shift work to higher risk of cardiovascular disease in women

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While working the night shift has been previously associated with higher risk for cardiovascular disease and cancer, a new study also links it to a higher risk in women for all-cause and cardiovascular disease mortality, as well as lung cancer mortality.

The study, published in the American Journal of Preventive Medicine, found that women working rotating night shifts for five years or more appeared to have a modest increase in all-cause mortality and fatal cardiovascular disease. The study also found that women with 15 years or more of rotating night shift work appeared to have a modest increase in lung cancer mortality, according to a press release.

The study focused on nearly 75,000 registered U.S. nurses, and analyzed 22 years’ worth of follow-up data compiled by the Nurses’ Health Study. Mortality from all causes appeared to be 11 percent higher for with six to 14 years of rotating night shift work, and death from cardiovascular disease appeared to be between 19 and 23 percent higher.

While the researchers found no association between rotating shift work and any cancer mortality, they did find a 25 percent increase risk for lung cancer in those who worked a rotating night shift for 15 or more years, according to the news release.

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

“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 said.

The study identified rotating shift work as working at least three nights per month in addition to days or evenings in the same month.