Constipation: an early sign of Parkinson's?

NEW YORK (Reuters Health) - People with a history of constipation may be at increased risk of developing Parkinson's disease down the road, research hints.

In a study, Dr. Walter A. Rocca at the Mayo Clinic in Rochester, Minnesota, and colleagues found a history of constipation about two times more frequent in a group of men and women with Parkinson's disease than in an age-matched group of men and women who did not have the disease.

Parkinson's disease is a degenerative brain disease that causes body tremors, rigid muscles, and difficulty walking and talking. The disease alters the body's autonomic nervous system, which controls spontaneous body processes such as heart rate, digestion, salivation, and bowel function.

Chronic constipation is common among people who suffer from Parkinson's and it has been suggested that constipation may precede the appearance of classic movement symptoms of the disease in some people. For example, in the Honolulu-Asia Aging Study, men who reported less frequent bowel movements had a significantly higher risk of Parkinson's disease over 24 years than men who reported more frequent bowel movements.

To investigate further, Rocca's team evaluated about 38 years of medical records of individuals living in Olmsted County, Minnesota. They compared constipation history in 196 men and women who developed Parkinson's at an average age of 71 years, and 196 Parkinson's-free "controls" of similar age and gender.

Roughly 36 percent of the Parkinson's patients had a history of constipation compared with only 20 percent of the controls, a significant difference.

After allowing for differences in age, smoking, coffee drinking, the use of constipation-inducing drugs, and constipation during the 19 years prior to the onset of Parkinson's disease, Parkinson's patients remained about two times more likely than controls to have a history of constipation.

The association between constipation and Parkinson's was evident long before the onset of the disease, the researchers note. "Indeed, the association remained significant when restricted to constipation documented more than 20 years before the onset of Parkinson's disease," they note in a report in the journal Neurology.

The findings, say the investigators, suggest that constipation is an early manifestation of the neurodegenerative process underlying Parkinson's disease. This study, Rocca added in comments to Reuters Health, "adds new evidence to accumulating literature" suggesting that Parkinson's disease has a very long preclinical period.

However, because constipation has many causes not specifically related to nervous system function it is not a specific marker for Parkinson's disease, Rocca noted.

Further investigations are needed to confirm and additionally evaluate the potential link between constipation and Parkinson's disease, Rocca said.

In the meantime, he suggests individuals with constipation focus on managing their current symptoms rather than worry about Parkinson's disease risk.

SOURCE: Neurology, November 24, 2009