Cigarette Smoking May Increase Risk for Alzheimer's Disease

A case-control study published in JAMA Network Open showed an apparent connection between cigarette smoking and greater amounts of Alzheimer's disease risk biomarkers, reports Healio . The investigators analyzed cerebrospinal fluid (CSF) biomarkers of neurodegeneration, neuroinflammation, neuroprotection, and oxidation among 191 adult men in China with and without significant cigarette exposure. The nonsmoking cohort included 104 participants with no history of substance use disorder or dependence. The active smoking group included 87 participants who consumed 10 or more cigarettes a day for one year. Outcomes indicated significantly lower mean CSF levels of amyloid-beta 42 and tumor necrosis factor alpha, and higher brain-derived neurotrophic factor, total superoxide dismutase, total nitric oxide synthase, inducible nitric oxide synthase, and constitutive nitric oxide synthase among the active smoking versus nonsmoking cohort. Smoking group members 40 years or older also had a negative correlation between total superoxide dismutase levels and amyloid-beta 42 levels. Subjects who smoked 20 cigarettes or more daily exhibited a positive correlation between tumor necrosis factor alpha and amyloid-beta 42 levels. The association between tumor necrosis factor alpha and amyloid-beta 42 levels was stronger than that of total superoxide dismutase and amyloid-beta 42 production.