José Obeso

Various studies have shown that smokers have a lower risk of developing Parkinson’s disease, but the causes remain unknown. A study has analysed the role played by carbon monoxide — a toxic gas produced by the combustion of tobacco — in this association. To this end, the team conducted a twelve-year follow-up study of more than half a million adults in China. The results show that regular smoking was associated with an increased risk of lung cancer, ischaemic heart disease, stroke and all-cause mortality, but with a lower risk of Parkinson’s disease. Most strikingly, amongst people who had never smoked, higher levels of exhaled carbon monoxide—which the authors measured—were associated with a lower risk of Parkinson’s disease. According to the study, published in JAMA Neurology, these findings demonstrate a possible protective role of carbon monoxide in the disease, rather than smoking itself.

Parkinson's disease is usually diagnosed when there is already extensive neuronal damage and symptoms are evident. Now, researchers at Cardiff University in the UK have used movement and sleep quality data from wearable accelerometers and concluded that they can help identify the disease early, years before clinical diagnosis. Although there is no effective preventive treatment, the authors propose that the tool can determine people at risk of developing Parkinson's disease and identify participants for clinical trials of neuroprotective treatments. The results are published in the journal Nature Medicine.