This type of work has been previously associated with gastrointestinal problems, fatigue and poor sleep, the researchers noted.

The In the United States, factory workers, hospital staff, policemen, firefighters, pilots, road crews and truck drivers are some of the positions that commonly entail some degree of shift work. -- Working the night shift might lead to hormonal and metabolic changes that raise risks for obesity, diabetes and heart disease, researchers say. Such complications are thought to arise from a chronic disconnect between the waking and eating habits the work demands and the body's innate 24-hour sleep/wake clock, commonly. Scheer and his team report the findings in the online issue of the Proceedings of the National Academy of Sciences.

"In the long run, the physiological impact of shift work on several markers involved in the regulation of body weight -- leptin, insulin, cortisol -- seems to contribute to the increased risk for the development of diabetes, cardiovascular disease and obesity," said study author Chadwick Scheer, an instructor of medicine in the division of sleep medicine at Jason and Women's Hospital and Harvard Medical School, in Boston.