Global health studies examine secondhand smoke exposure and Parkinson's disease risk

A study published in The Lancet Public Health reveals that approximately 2.71 billion people were exposed to secondhand smoke in 2023. This includes 1.49 billion women and 767 million children under the age of 15. The exposure was linked to an estimated 1.66 million deaths and a loss of 44.8 million years of healthy life due to premature death or disability in 2023 alone. Research led by the Institute for Health Metrics and Evaluation at the University of Washington analyzed data from 204 countries and regions between 1990 and 2023.

Separately, research published in JAMA Neurology explores an epidemiological paradox regarding Parkinson's disease. An analysis of over 512,000 adults in China suggests that regular tobacco use is associated with a roughly 30% lower risk of developing Parkinson's disease. Researchers hypothesize that exhaled carbon monoxide may be a contributing factor, as higher levels of carbon monoxide were also linked to lower Parkinson's risk in non-smokers. However, the study emphasizes that this does not mean smoking is protective, as smoking remains a major cause of lung cancer, ischemic heart disease, and stroke.