How Alcohol Affects Parkinson's Disease Risk

Drinking alcoholic beverages is not associated with Parkinson’s disease (PD) risk, according to a new study published in the June issue of PLOS ONE. However, in additional analyses the study did find that among those who drink only beer, greater consumption was associated with lower risk for PD and among those who consumed only liquor, greater consumption was associated with higher risk for PD. No association was found between wine and PD risk.

While previous studies have found that cigarette smoking and coffee consumption are associated with a lower risk of Parkinson’s disease, research on alcohol consumption and PD risk has shown conflicting data. The researchers, led by Rui Lui, Ph.D., of the National Institute of Environmental Health Sciences in Research Triangle Park, NC, were interested in learning more about alcohol’s effects on Parkinson’s disease risk and how specific types of alcoholic beverages might influence that risk.

The study looked at 306,895 people (ages 50 to 71 at the time) who participated in the 1995-1996 NIH-AARP Diet and Health Study, which collected detailed lifestyle and dietary information from participants. Researchers followed up with study participants and compared the alcohol consumption of the 1,094 people who were diagnosed with PD between 2000 and 2006 and those who did not develop the disease.

• Overall, total alcohol consumption was not associated with Parkinson’s disease risk.
• People who drank beer only and consumed one or more beers per day had a 59 percent lower risk of PD than non-alcohol drinkers.
• People who drank liquor only and consumed one or more drinks per day had a more than two-fold higher risk of PD than non-alcohol drinkers.

The major finding of this study is that there is no association between total consumption of alcoholic beverages and future risk of Parkinson’s disease.

This is in contrast to caffeine consumption and smoking which are associated with lower risk for PD.

Researchers have tried to explain the association between caffeine and smoking to PD in one of two ways - either that there is something protective in caffeine or in smoking which reduces the risk for PD, or, that people with PD are less predisposed to addiction, possibly because of reduced dopamine even before disease onset. The fact that alcohol consumption is not associated with reduced PD risk argues against the second hypothesis.

In additional analyses, the researchers found that among those who consume only beer, higher consumption was associated with a lower PD risk and among those who consume only liquor, higher consumption was associated with a higher PD risk. It is very difficult to interpret these findings because of the opposite effects of beer and liquor consumptions. Plus this study reports on an association between a substance (alcohol) and an outcome, but is not designed to prove definitive cause and effect.

The study did not investigate the reasons why beer and liquor affect Parkinson’s disease risk. One proposed mechanism would be that beer consumption elevates plasma urate which is associated with lower PD risk.

The higher risk of Parkinson’s disease among liquor drinkers may be due to the detrimental effects of liquor’s high ethanol content and its lack of vitamins and antioxidants.

Research on alcohol consumption and Parkinson’s disease still shows conflicting data. People who do not drink alcohol should not start drinking beer to try to prevent PD.

This material was sent in from Parkinson's Disease Foundation.