Demanding, stressful or insecure jobs may motivate workers to show up even when they should stay home sick, a research review suggests.

Understanding what motivates workers to remain on the job when they're sick may help employers develop sick-day policies that may be more effective at preventing the spread of contagious diseases in the workplace, study co-author Gary Johns, a business and management researcher at Concordia University in Montreal, said by email.

"In the case of contagious illness, the spread of the illness to co-workers and customers or clients is an obvious concern," Johns said. "On the other hand, if illness is neither contagious nor debilitating, it might be self-affirming for people to go to work when not perfectly fit."

Johns and co-author Mariella Miraglia of the Norwich Business School at the University of East Anglia in the U.K. analyzed data from 61 previous studies involving more than 175,000 people in more than 30 countries to assess what might motivate people to come to work when they were sick.

The two researchers refer to working while sick as "presenteeism."

In the studies they analyzed, presenteeism was often linked to workplace policies to reduce absenteeism, such as disciplinary actions, limited paid sick leave, or medical certification required for sick time, the analysis found.

Job demands also came into play, with heavy workloads, understaffing, overtime and looming deadlines all motivating people to work while sick.

"Tight restrictions on paid sick leave, such as requiring a doctor's note to validate an employee's illness," can limit the effectiveness of giving people paid time off to prevent the spread of disease in the workplace, Dr. Eric Widera, a researcher at the University of California, San Francisco, who wasn't involved in the study, said by email.

One shortcoming of the analysis is that the researchers lacked data to properly assess the role of depression and mental health in presenteeism, the authors acknowledge in the Journal of Occupational Health Psychology. It's possible that workers suffering from mental illness might not perceive themselves as working while sick.

Many workers may believe their jobs are on the line if they stay home, or feel that they can't afford the lost income from an unpaid day off, noted Supriya Kumar, a public health researcher at the University of Pittsburgh who wasn't involved in the study.

Workers who feel they have no choice but to work while sick can still help prevent the spread of contagious diseases like influenza by avoiding face-to-face conversations with co-workers, and by washing their hands frequently, Kumar said by email.

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Still, managers who realize why people work when they're sick may be able to change policies so employees are motivated to stay home when they're contagious.

"When people stay home when sick with a contagious disease like influenza, they actually reduce the likelihood of future illness among co-workers and thus reduce absenteeism in the workplace," Kumar said. "Managers who realize this and promote stay-at-home behavior in cases of infectious illness are likely to have a more healthy workplace."