Alcohol Doesn't Protect From Parkinson's
Findings Dispute Notion of 'Parkinson's Personality'
May 15, 2003 -- New research argues against a direct relationship between Parkinson's disease and an aversion to addictive behaviors. The findings challenge the idea of a so-called 'Parkinson's personality' in people predisposed to develop the disease.
Investigators at the Harvard School of Public Health hypothesized that people who develop Parkinson's disease are less likely to drink heavily earlier in life than people who never get the disease, but they found little evidence that this was true in their study involving roughly 140,000 people.
"If the Parkinson's personality hypothesis is correct, you would expect to find that heavy drinking was protective against Parkinson's," lead researcher Miguel A. Hernan, MD, tells WebMD. "But with these and other findings (the hypothesis) starts to look a bit shaky."
The suggestion that engaging in addictive behaviors is somehow protective against Parkinson's disease stems from more than 40 studies finding that the disease is far less common among people who smoke cigarettes or drink large amounts of coffee. Animal studies suggest that caffeine and certain components of cigarette smoke are protective against Parkinson's disease. But an alternative explanation is that people predisposed to develop Parkinson's disease have a natural aversion to addictive behaviors, due to either genetic or metabolic influences.
Parkinson's disease is associated with a degeneration of nerve cells in the brain that produce the chemical dopamine, and dopamine is involved in addictive behavior. With this in mind, Hernan and Harvard colleagues examined alcohol consumption and Parkinson's disease risk among people participating in two large ongoing prospective trials -- the Nurses' Health Study and the Health Professional's Follow-up Study. Their findings are reported the latest online edition of the Annals of Neurology.
Some 88,000 women and 47,000 men reported their alcohol intake, along with other dietary information, every two years as part of their participation in the study. The researchers found no difference in Parkinson's rates between people who drank little or no alcohol and those who drank moderately or every day.
People who drank moderate amounts of beer did have a 30% reduction in Parkinson's disease rates, but this was not seen for other types of alcohol, and Hernan says it is unclear if this association is real. He says that because the association was only seen for beer, it is likely that some component other than ethanol is protective against Parkinson's disease.
"Alcohol does not seem to play an important role in Parkinson's risk," he says.
But Parkinson's researcher William K. Scott, PhD, of Duke University, says it would be hard to draw firm conclusions about the role of alcohol in Parkinson's disease from this study because people often do not tell the truth when asked about their alcohol consumption.
"The findings do seem to be consistent with what other people are finding with respect to alcohol and Parkinson's disease," says Scott, who is with Duke's Udall Parkinson's Disease Research Center of Excellence. "The findings may not support a Parkinson's personality, but it certainly doesn't rule it out."