Does smoking protect against Parkinson’s? A study of half a million people points to carbon monoxide, revealing a surprising clue in cigarette smoke

A recent study indicates that carbon monoxide might be responsible for lowering the risk of Parkinson's disease, as opposed to nicotine. Researchers discovered a correlation between elevated carbon monoxide levels and a decrease in the disease's occurrence, with this trend remaining evident in non-smokers. This suggests a possible protective factor.