Study: Alcohol, Parkinson’s Not Linked

Researchers at the Harvard School of Public Health (HSPH) have found that people who drink alcohol do not have a reduced risk of Parkinson’s disease, challenging the link between Parkinson’s and an avoidance of addictive behaviors that had been suggested by previous studies.

Using data from two long-term studies, the researchers examined risk factors for Parkinson’s disease—a progressive neurological condition that causes tremors, stiff limbs and difficulty in movement—and found there was “no significant difference between drinkers and non-drinkers,” according to lead researcher Miguel Hernan, an assistant professor of epidemiology at HSPH.

The study—made by an HSPH team that included Hernan and Associate Professor of Nutrition and Epidemiology Alberto Ascherio—has been investigating possible risk factors for Parkinson’s disease.

It was published online last month in the Annals of Neurology, the journal of the American Neurological Association. It will be appearing in the print version of the journal soon, Hernan said.

The study represents the latest findings to incorporate the Nurses’ Health Study—a set of data collected on 120,000 female nurses nationwide from 1976 to the present—and the Health Professionals Follow-Up Study, a counterpart data set begun in 1986 to collect information on about 50,000 male health care professionals.

Every two years, participants in the studies fill out a questionnaire including questions about their diet, exercise and personal habits. Researchers analyze the data to find correlations between lifestyle factors and the risk of developing certain diseases.

According to the National Parkinson Foundation website, researchers still do not fully understand what causes Parkinson’s, which affects about 1.5 million Americans, including 1 in 100 who are over the age of 60.

Hernan said previous studies have found that smokers and coffee drinkers are less likely to develop Parkinson’s disease—at least among men. This has led some scientists to posit that the disease is positively correlated with a certain personality type whose tendency is to avoid addictive behaviors.

But with the new results showing no connection between alcohol and the risk of developing the disease, this theory is being questioned.

“If people with Parkinson’s have this special type of personality that leads them to avoid behaviors that are addictive, then we would expect that they drink less too,” said Hernan, who added that his latest results have not supported this theory.

The study did show that drinking beer was associated with a lower risk of Parkinson’s, but the consumption of other types of alcohol was not. Hernan said that this could be because beer increases the level of uric acid in the blood, which has been shown in other studies to be associated with a lower occurrence of Parkinson’s.

He said that researchers at Massachusetts General Hospital are conducting animal studies to investigate whether cigarette smoke or caffeine have protective benefits.

The studies have shown so far that caffeine does reduce the likelihood that mice will develop certain diseases, while alcohol has had no effect. But Hernan cautioned that such theories are still “based on speculation,” and at this point, it is too early to draw any conclusions.

—Staff writer Jessica R. Rubin-Wills can be reached at rubinwil@fas.harvard.edu.