In the heyday of cigarette smoking, a pack a day was “just what the doctor ordered.” Of course, the purported health benefits of smoking have been largely debunked, and cigarettes today are associated with serious health hazards.
But smoking may still have at least one advantage: protection against the development of Parkinson’s disease. A large-scale study published in Wednesday’s online edition of the journal Neurology further bolsters the connection and concludes that the longer you smoke, the less likely you are to develop the illness.
In 2007, researchers at the Harvard School of Public Health analyzed 11 separate studies and concluded that cigarette smoking protected against Parkinson’s but that benefits waned once a smoker quit. But the effect was a strong one: Smokers were 73 percent less likely to suffer from Parkinson’s than those who’d never lit up.
The latest study, while showing less dramatic results, offers a larger sample of subjects and could yield new clues about the mechanism by which cigarettes improve the brain’s resiliency to Parkinson’s.
A team at the National Institutes of Environmental Health Sciences examined 305,000 men and women over age 50. At a 10-year follow-up, half of 1 percent of the study’s participants had developed Parkinson’s.
More years of smoking were associated with less risk. Those who smoked for less than a decade had a 4 percent lower risk than nonsmokers, compared with a 41 percent reduced risk among participants who’d been lighting up daily for more than 30 years.
The number of cigarettes smoked didn’t appear to have any effect.
The study’s lead researcher, Dr. Honglei Chen, said he doesn’t foresee tobacco or other cigarette ingredients being considered as potential treatments for Parkinson’s. But the information “could guide the development of studies on various tobacco components … to help understand the relationship between smoking and Parkinson’s disease,” he told Health Day.
Further research could determine which chemicals are responsible for bolstering the brain against the illness, which targets the central nervous system and causes dozens of symptoms, of which physical tremors are the most obvious.
The cause of Parkinson’s still eludes researchers, but some suspect exposure to environmental toxins is to blame. One study of 143,000 adults concluded that those who’d been exposed to heavy doses of pesticides were 70 percent more likely to develop the disease.
The new research is good news for ongoing efforts to better understand Parkinson’s disease. But the cons of smoking still outweigh the pros, so the study’s authors are advising against lighting up as a preventive measure.