Michael Wirth, MSPH, PhD, of the University of South Carolina, Columbia, and colleagues analyzed the relationship between shiftwork and pro-inflammatory diet using data from a nationwide sample of employed adults. Based on diet questionnaires, the researchers calculated a "dietary inflammatory index" (DII) for each individual. The greater the DII score, the more pro-inflammatory the diet.

With adjustment for other factors, shiftworkers had an elevated DII, compared to day workers. The difference was significant for rotating shiftworkers (those who worked varying shifts): average DII 1.07, compared to 0.86 for day workers.