Men who suffer from constipation are more likely to get diagnosed with the progressive brain disease Parkinson's. Scientists have little idea why this should be the case, although some have suggested that the disease may have some effect on the function of the gut long before it manifests itself elsewhere.
Dr Robert Abbott, who led the research, said: "It could help us more effectively identify people with early or suspected disease or people at high risk of developing the disease in the future."The large study, part of the Honolulu Heart Program, looked at 6,456 aged between 51 and 75 who were followed for 24 years.
Constipation was defined as having less than one bowel movement a day - approximately 5% of the population are thought to be affected to this degree. Men who were constipated were 2.7 times more likely to develop Parkinson's as men who had an average of one bowel movement per day.
The researchers took into account differences between the men in terms of age, coffee smoking, laxative use and intake of fruit, vegetables and grains.Dr Abbott said: "Adjustments for those factors made no change in the results - the strong tie between bowel movement frequency and the risk of Parkinson's disease remained."
However, the fact that relatively few people develop Parkinson's means that most people with constipation will never get it. Dr Abbott, said: "However, if people have constipation that does not respond to use of laxatives along with other factors, such as a family history of the disease or other motor problems, then they may be at higher risk of developing the disease." The research was published in the journal Neurology.