U. S. researchers have warned that shift workers may be more at risk than others for irritable bowel syndrome.

Abdominal pain is more common among nurses working rotating shifts, found researchers at the University of Michigan Medical School in Ann Arbor.

Nurses participating in shift work, particularly those who participate in rotating shift work have a higher prevalence of irritable bowel syndrome and abdominal pain, suggests the study, published in the American Journal of Gastroenterology. This association was independent of sleep quality.

Study lead author, Dr. Sandra Hoogerwerf, says in a statement, "We know the colon has its own biological clock and that's what increases the likelihood of having a bowel movement in the first six hours of the day. The question now for further research is if irritable bowel syndrome and abdominal pain is an underlying manifestation of a circadian rhythm disorder."

Nurses, 85 percent of them women, were evaluated by Hoogerwerf and colleagues by classifying them into three groups -- 214 working permanent day shifts, 110 working permanent night shifts and 75 working rotating shifts between day and night. (With Inputs from Agencies)