Shift Workers More Likely to Have Proinflammatory Diet

People who work evenings and nights appears to have worse diets than daytime workers, raising their risks for obesity, heart disease, and diabetes.

People who do shiftwork (work evenings or night shifts) are more likely to have a diet that promotes chronic inflammation—which may partly explain the health risks associated with shiftwork—obesity, heart disease, and diabetes, according the results of a study in the February issue of Journal of Occupational and Environmental Medicine.1

Investigators led by Michael Wirth, MSPH, PhD, of the University of South Carolina, Columbia and colleagues from the Centers for Disease Control and Prevention, analyzed the relationship between shiftwork and pro-inflammatory diet using data from a nationwide sample of employed adults (National Health and Nutrition Examination Survey [NHANES]). Based on diet questionnaires, the researchers calculated a "dietary inflammatory index" (DII) for each individual. The greater the DII score, the more proinflammatory 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. Women had higher DII values than men. Among women, the DII was higher for evening or night shiftworkers compared to day workers: 1.48 versus 1.17.

Shiftwork has been linked to increased risks of disease, including high blood pressure, obesity, cardiovascular disease, and diabetes. Poor eating habits may contribute to some of these risks. Western-style diets with higher levels of calories and fats have been linked to increased inflammation, compared to Mediterranean diets high in fruits and vegetables.

The DII provides a way of measuring how "proinflammatory" a person's diet is. A recent study of police officers found a higher DII in officers doing shiftwork. The new study suggests a similar elevation in DII among shiftworkers in the general population.

It's still unclear how much of an impact the elevated DII would have on health, but a proinflammatory diet might be one factor contributing to shiftwork-related health risks. "Inflammatory diets represent a target for behavioral interventions to reduce the health impacts of shiftwork," Dr. Wirth and coauthors stated. They add that interventions should address other important lifestyle factors as well, including physical activity, proper sleep, and light exposure.