A new large-scale study has found that changes in smoking behaviour over time may significantly impact the risk of developing Parkinson’s disease (PD) and all-cause mortality, highlighting the complex interplay between lifestyle and neurodegenerative disorders.
Persistent Smoking Linked to Lower Parkinson’s Disease Risk
Researchers conducted a retrospective cohort study including 410,489 participants aged 40 years and older who participated in three examination periods of the Korean National Health Screening. Participants were categorised into four groups based on their smoking trajectories: persistent smokers, recent quitters, sustained quitters, and relapsed smokers.
Over a median follow-up of 9.1 years, persistent smokers demonstrated the lowest risk of PD. Recent and sustained quitters exhibited a significantly higher risk of PD than persistent smokers (subdistribution hazard ratio [sHR] 1.60 and 1.61, respectively), while relapsed smokers showed no difference compared with persistent smokers.
The findings suggest that current smoking status, rather than cumulative exposure, primarily influenced PD risk, as relapsed smokers showed a markedly different risk compared with recent quitters despite having the same number of smoking time points. Even short-term abstinence of around two years did not attenuate the apparent protective association.
Mortality Benefits Highlight the Value of Quitting
While persistent smoking appeared to lower PD risk, all-cause mortality told a different story. Sustained quitters had a 17% lower risk of death, and recent quitters experienced a marginal 3% reduction, whereas relapsed smokers’ mortality did not differ significantly from persistent smokers. These results emphasise that early cessation provides substantial survival benefits despite the nuanced relationship between smoking and PD.
Parkinson’s disease, the second most common neurodegenerative disorder, is characterised by motor symptoms including bradykinesia, rigidity, and tremor, alongside nonmotor manifestations that reduce quality of life. Environmental factors, such as cigarette smoking, have been paradoxically associated with a lower risk of PD, potentially through neuroprotective mechanisms involving nicotine and carbon monoxide. However, premature death among smokers can obscure this relationship, making competing risk analyses critical for accurate interpretation.
The authors caution that the study assessed smoking status at three time points only and was predominantly male, meaning subsequent behavioural changes and sex differences require further investigation. Nonetheless, this longitudinal analysis provides new insights into how dynamic smoking patterns influence both neurological health and overall survival.
Reference
Ahn SH et al. Dynamic smoking patterns and risk of Parkinson disease and all-cause mortality. Neurology. 2026; DOI:10.1212/WNL.0000000000214651.
Featured image: Leo Rohmann on Adobe Stock
