A study published in JAMA Neurology indicates that higher levels of carbon monoxide in exhaled breath may be associated with a lower risk of Parkinson's disease (PD). This finding was observed in a large population, including non-smokers.
Dr Michael A. Schwarzschild, Professor of Neurology at Harvard Medical School, noted that higher carbon monoxide levels in non-smokers, comparable to those in light or moderate smokers, predicted a lower risk of Parkinson's years later. Crucially, non-smokers with these higher levels did not show an increased risk for lung cancer or other negative health effects linked to smoking.
Dr Toni Pitcher, Senior Research Fellow in Parkinson’s epidemiology at the University of Otago, Christchurch, highlighted that this is the first large-scale demonstration of Parkinson's being less common in individuals with higher exhaled carbon monoxide levels who do not have a smoking history. Carbon monoxide is known to have anti-inflammatory effects and can help counteract cell stress in the brain.
The study strengthens the rationale for ongoing research, including a trial of low-dose carbon monoxide in non-smokers with Parkinson's, led by Dr Schwarzschild. However, experts caution that the findings need to be replicated in other populations, and the follow-up period for the study was relatively short for a disease with a late age of onset like Parkinson's.