- Explain to patients who ask that in addition to the known contributions of second-hand or passive smoke to cancer and heart disease risk, this study suggests but does not demonstrate significantly that long-term exposure to someone else's smoke may increase the risk for dementia.
- This study was published as an abstract and presented orally at a conference. These data and conclusions should be considered to be preliminary as they have not yet been reviewed and published in a peer-reviewed publication
BOSTON, May 1 -- Long-term exposure to second-hand smoke may be a risk factor for dementia in the presence of subclinical carotid artery disease, said investigators here.
In a subset of patients in the Cardiovascular Health Study, those who had a subclinical carotid stenosis and lived with a smoker for 30 years or more had a 2.5-fold greater risk for dementia than those free of cigarette smoke exposure, found statistician Thaddeus Haight, M.A., of the University of California at Berkeley.
In contrast, second-hand smoke exposure in the absence of carotid disease was not a significant risk factor for dementia, reported Haight at the American Academy of Neurology meeting
The findings did not meet the test of statistical significance, but pointed to second-hand or passive smoking as a possible additive risk factor for dementia.
"It's actually quite plausible that second-hand smoke, given its effects on the cardiovascular system, can affect the risk of dementia indirectly through the clinical cardiovascular disease pathway," he said. "But what's less well known is whether there are actually direct effects that may be neurotoxic effects with respect to people's cerebral functioning, and the neurotoxic effects of second-hand smoke with respect to some neurodegenerative process."