Previous studies suggested that people with Parkinson's disease are more likely than other people to be smokers and coffee drinkers.
To see if this is true, Dana B. Hancock and William K. Scott, PhD, studied 356 people with Parkinson's disease and 317 of their family members. By using family members as a control group, the researchers were able to look at people with similar genetic, environmental, and behavioral characteristics.
They found that Parkinson's patients were 44% less likely than their family members ever to have smoked. They were also 42% less likely to be high-level caffeine users.
The common painkillers known as nonsteroidal anti-inflammatory drugs (NSAIDs) -- which include ibuprofen, naproxen, and aspirin -- have also been found to protect against Parkinson's. But Hancock and colleagues found no link between painkiller use and Parkinson's.
How might cigarettes and caffeine protect a person from Parkinson's? Nobody knows. But Parkinson's disease runs in families, suggesting that genetic effects play a role. Smoking and caffeine use may interfere with these effects, Hancock and colleagues suggest.
The findings appear in the April issue of Archives of Neurology. The research came from Duke University in Durham, N.C. Hancock and Scott are now at the University of Miami.