Why is smoking linked to a lower risk of Parkinson's?
· Medical Xpressedited by Lisa Lock, reviewed by Andrew Zinin
Lisa Lock
Scientific Editor
Meet our editorial team
Behind our editorial process
Andrew Zinin
Chief Editor
Meet our editorial team
Behind our editorial process Editors' notes
This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility:
fact-checked
peer-reviewed publication
trusted source
proofread
The GIST Add as preferred source
A link between carbon monoxide and Parkinson's disease may explain why smokers are at lower risk of developing the condition, according to international research. The team monitored the health of 512,701 Chinese adults over 12 years, including 1,131 people with Parkinson's and 2,949 with other neurodegenerative diseases. They investigated the impact of smoking using self-reported smoking frequency and measurements of carbon monoxide in breath—usually an indicator of smoking. The results are published in the journal JAMA Neurology.
The researchers say both smoking history and exhaled carbon monoxide were linked to a lower risk of Parkinson's disease. While smokers generally had higher carbon monoxide levels in their breath, the researchers say nonsmokers with high carbon monoxide levels also had a lower risk of Parkinson's—suggesting carbon monoxide may independently protect against the disease.
Associate Professor Andrea Bugarcic from the National Center for Naturopathic Medicine at Southern Cross University says, "This study demonstrates the power of longitudinal patient data. Using observational research methodology, this study investigated the risk of developing neurodegenerative diseases in a large but geographically focused sample. Combining what patients say about their lives, such as smoking and environment, with measurements we can make as scientists, such as exhaled CO, the study links higher exhaled CO to a lower risk of Parkinson's disease only, not other causes of dementia.
"While increased exhaled CO is linked to smoking, the current study also points out that risk levels for nonsmoking and smoking patients are the same. Collectively, the study not only points out a possible mechanism for the previously observed protective effects of smoking on Parkinson's disease risk, but it also reminds us that CO release is a larger environmental consideration.
"Despite the controversial outcomes and limitations of this study, my perspective is that researchers across the methodological spectrum should take on the challenge set out by this study—understand why and how exhaling more CO links specifically to lower Parkinson's disease risk. As a scientist, my contribution would be understanding molecular puzzles using a precision medicine approach that can then lead to human studies on specific groups of patients. This is where studies like this matter—they give a voice to patients that then mobilizes all that science has to offer, from understanding why to ensuring a grounded approach to therapeutic development."
Publication details
Clara Bueno Lopez et al, Smoking, Exhaled Carbon Monoxide, and Risk of Parkinson Disease, JAMA Neurology (2026). DOI: 10.1001/jamaneurol.2026.3037
Journal information: Archives of Neurology
Key medical concepts
Parkinson's DiseaseCarbon Monoxide
Clinical categories
Neurology Provided by University of Oxford Who's behind this story?
Lisa Lock
BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021. Full profile →
Andrew Zinin
Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →
Citation: Why is smoking linked to a lower risk of Parkinson's? (2026, September 8) retrieved 9 September 2026 from https://medicalxpress.com/news/2026-09-linked-parkinson.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.