Ten years or more of such shift work decreased the odds of healthy aging by 20%.

Shift work is a staple of hospital nursing, and several large studies have found that rotating night shifts, in particular, are associated with increased mortality. Now, an international group of researchers has found evidence of significant harm to nurses’ overall health from rotating night shifts.

Detrimental effects on healthy aging.

Published in the May issue of JAMA Network Open, the study by Shi and colleagues found that 10 or more years of night shift work—defined as at least three nights per month in addition to day and evening shifts—conferred 20% decreased odds of healthy aging. The study’s end point for healthy aging was reaching age 70 without major chronic disease, physical limitations, memory impairment, and mental health issues. The association between a history of night shift work and deteriorated health was unchanged when age, body mass index, or lifestyle factors were considered. Although the mechanisms underlying these effects are unknown, the authors pointed to several possibilities, including altered circadian rhythms since they are important to metabolic regulation and disruptions may impair physical health.