Secondhand Smoke, Vascular Disease, and Dementia Incidence: Findings From the Cardiovascular Health Cognition Study

Abstract

Recent studies have found that smoking is associated with an increased risk of dementia, but the effects of secondhand smoke (SHS) on dementia risk are not known to have previously been studied. The authors used Cox proportional hazards marginal structural models to examine the association between self-reported lifetime household SHS exposure and risk of incident dementia over 6 years among 970 US participants in the Cardiovascular Health Cognition Study (performed from 1991 to 1999) who were never smokers and were free of clinical cardiovascular disease (CVD), dementia, and mild cognitive impairment at baseline. In addition, because prior studies have found that SHS is associated with increased risk of CVD and that CVD is associated with increased risk of dementia, the authors tested for interactions between SHS and measures of clinical and subclinical CVD on dementia risk. Moderate (16-25 years) and high (>25 years) SHS exposure levels were not independently associated with dementia risk; however, subjects with >25 years of SHS exposure and >25% carotid artery stenosis had a 3-fold increase (hazard ratio = 3.00, 95% confidence interval: 1.03, 9.72) in dementia risk compared with subjects with no/low (0-15 years) SHS exposure and < or =25% carotid artery stenosis. High lifetime SHS exposure may increase the risk of dementia in elderly with undiagnosed CVD.

The projected effect of risk factor reduction on Alzheimer's disease prevalence

“…The most likely mechanism underlying the association between smoking and AD is vascular disease. 78 Smoking contributes to a variety of subclinical and clinical vascular disorders including atherosclerosis and cerebrovascular disease 79 which, in turn, could lead to increased risk of AD. 80, 81 However, tobacco smoke also contains hundreds of chemicals that are known to be neurotoxins and could contribute to AD risk through oxidative stress or inflammatory processes.…”

O3‐06‐06: The Projected impact of risk factor reduction on Alzheimer's disease prevalence

“…The most likely mechanism underlying the association between smoking and AD is vascular disease. 78 Smoking contributes to a variety of subclinical and clinical vascular disorders including atherosclerosis and cerebrovascular disease 79 which, in turn, could lead to increased risk of AD. 80,81 However, tobacco smoke also contains hundreds of chemicals that are known to be neurotoxins and could contribute to AD risk through oxidative stress or inflammatory processes.…”

Alzheimer’s Disease: A Clinical Perspective

“…Strong epidemiological evidences suggested that cardiovascular risk factors and vascular disease are associated with an increased risk of symptomatic AD [27].Thus, studies revealed age-dependents associations with AD for several aging-related conditions. The most important cardiovascular risk factors for subsequent AD include cigarette smoking [28,29], heavy alcohol consumption [30], midlife high blood pressure [31], atrial fibrillation and heart failure [32], spontaneous cerebral emboli [33], midlife obesity or central adiposity as well as low BMI in late-life [34][35][36], midlife high cholesterol levels [37], diabetes mellitus and impaired glucose regulation [38][39][40], neuroinflammation [41,42], and elevated plasma and total homocysteine levels [43].…”