NIOSH Training for Nurses on Shift Work and Long Work Hours

Diseases and Shift Work

Research indicates shift workers may be at higher risk for disease

Scientists warn that shift workers may be at somewhat higher risk for several types of diseases. Research of shift workers is challenging and has some limitations, however. It is difficult for researchers to control for many factors that may influence development of disease in shift workers, such as smoking, diet, and work demands. Another challenge is that it generally takes years for chronic disease to become apparent. Also, workers generally are not randomly assigned to work schedules but self-select their work shift to some extent. Persons who feel that they could not tolerate rotating or night shifts tend to avoid those jobs. This “healthy worker effect” tends to underestimate the negative impacts of shift work schedules.

Evidence for the link between shift work and health risks also comes from research on sleep and circadian rhythms.

Current scientific evidence suggests shift workers may be at higher risk for these health problems:

• Cardiovascular disease
• Gastrointestinal disorders
• Psychological disorders
• Cancer (breast cancer has been most researched)
• Diabetes mellitus
• Adverse reproductive outcomes
• Difficulty managing chronic diseases (see Module 4 on Individual Differences)