Smoking status influences Parkinson's disease risk and mortality outcomes

A new study of smokers finds that currently smoking is associated with a lower risk of developing Parkinson's disease, but quitting smoking was associated with a lower risk of death. The study was published on February 25, 2026, in Neurology^®, the medical journal of the American Academy of Neurology. The study does not prove that smoking prevents Parkinson's; it only shows an association.

"The severe health risks of smoking cannot be overlooked, as it remains a leading cause of preventable death and contributes to heart disease, cancer and chronic lung disorders," said study author Jun-Hyuk Lee, MD, PhD, of Eulji University School of Medicine in Seoul, South Korea. "While our study found smokers who quit showed a higher risk of Parkinson's disease than those who were currently smoking, it also found they had a lower risk of death. The health benefits of quitting smoking remain substantial and clear."

The study involved more than 410,000 adults in South Korea who were smokers at the beginning of the study. Their average age was 52, and they were followed for an average of nine years.

Participants completed health screenings at the start of the study, about two years later, and then another two years later. They were asked how much and how often they smoked.

Researchers divided participants into four groups: persistent smokers who never quit, relapsed smokers who quit a couple years into the study but then resumed smoking, recent quitters who smoked the first four years of the study and then quit, and sustained quitters who quit early in the study and never resumed smoking.

During the study, 1,794 people developed Parkinson's disease: 0.33% of persistent smokers, 0.41% of relapsed smokers, 0.67% of recent quitters and 0.71% of sustained quitters.

Also, 31,203 people died, including 7.24% of persistent smokers, 8.09% of relapsed smokers, 8.76% of recent quitters and 7.91% of sustained quitters.

After adjusting for factors such as income level, alcohol use and physical activity, researchers found that persistent smokers had the lowest risk of developing Parkinson's disease. Recent quitters and sustained quitters had a 60% to 61% higher risk of Parkinson's compared to persistent smokers. Relapsed smokers had a risk similar to persistent smokers.

When looking at risk of death, researchers found that sustained quitters had a 17% lower risk of death and recent quitters had a 3% lower risk compared to persistent smokers. Relapsed smokers had the same rate as persistent smokers.

"Overwhelming evidence from multiple previous studies shows quitting smoking is much better for long-term health overall," Lee said. "Our study suggests a lower risk of Parkinson's is not necessarily associated with how long someone smokes, but rather if they are currently smoking. Future studies are needed to better understand which components of smoking contribute to the reduced risk, and to develop safe and targeted therapies that replicate the effects of smoking for Parkinson's without the harmful health consequences."

A limitation of the study was that data was self-reported, so people providing responses may not have recalled all information accurately. Also, the participants were mostly Korean male participants, so results may not be generalizable to women or other populations.