Workers who get less than 11 hours of rest between shifts may be more likely to take sick leave, a Norwegian study suggests.
"Quick returns," defined as breaks shorter than 11 hours between the end of one shift and the beginning of another, were tied to a 21 percent increase in the odds of nurses taking sick leave the following month.
"Recent studies suggest these rapid changeovers can be associated with equal or even worse effects on sleep and fatigue than night work," said lead study author Oystein Vedaa of the University of Bergen.
"Our study also suggests short time for rest between shifts predicts sick leave and night shifts do not," Vedaa told Reuters Health by email. "The importance of rest time between shifts has received little attention in previous research."
Vedaa and colleagues looked at shift work and sick leave data for 3,700 nurses and nurses' assistants at Haukeland University Hospital, one of four public hospitals in western Norway. They asked nurses who worked more than 18 hours per week to participate in a survey, and 1,538 answered questions about themselves as well as their work schedules and sick leave.
More than 80 percent of nurses had quick returns during the year and, on average, each had three quick returns per month. More than 70 percent had at least one sick day during the year, averaging one sick leave day per month. Quick returns increased the risk for sick leave during the following month. In addition, prior sick leave increased the risk for future sick leave.
Other variables, including sex, age, marital status, children living at home and number of hours worked were not associated with more sick leave. In fact, experience with shift work, measured in years, was associated with a reduced risk for sick leave spells. Researchers also found no link between increased sick leave and personality characteristics associated with high tolerance for shift work, such as high flexibility, low drowsiness after sleep loss and low preference for the morning.
The European Working Time Directive says workers are entitled to a minimum 11 hours of daily rest during a 24-hour period. Some healthcare workers in some European countries, however, are exempt from these guidelines.
Since quick returns are usually not necessary to maintain staffing, they should be eliminated in shift schedules, the study authors write in the Journal of Occupational and Environmental Medicine.
"We cannot abolish night work, however, it should be an easy thing for shift planners to eliminate short rests between shifts," Vedaa said. "This seems worthwhile considering it may help reduce sick leave - and the associated costs."
Although the study focuses on nurses, the findings could help shift work planning for doctors and medical students as well, said Tom Smith of the University of Chicago National Opinion Research Center, who wasn't involved with the study. Smith and colleagues have researched U.S. workers' beliefs about and experiences with sick leave in the workplace.
"We know the serious implications of this," Smith told Reuters Health. "When people are overworked and overburdened, there are more accidents and more mistakes."
The study focuses on healthcare workers, Smith said, though he would like to see future studies about pilots, bus drivers and other shift-work positions that may face short-break issues. He'd also like to see studies in other countries such as the U.S. because of differences from Norway in demographics and socioeconomic status.
"In addition, a higher response rate would tell us more about what's typical of all nurses," said Smith.
The clinical implications of short breaks between shifts and sick leave are important as well, he said. Quick returns are bad for nurses, which may indicate the effects are bad for patients, too.
"If nurses are more likely to become sick, then are they forgetting to give medicine or failing to check up on patients?" he said. "We should think about the potential health care mistakes."