February 18, 2009

Link Found Between Second-Hand Smoke, Dementia

Lighting up not only is dangerous to your own health, but it could actually cause dementia in the people around you.

A new study in the British Medical Journal finds that exposure to second-hand smoke could increase the risk of developing dementia and other forms of cognitive impairment.

Researchers said previous studies have already established a possible link between active smoking and cognitive impairment and a link between exposure to second-hand smoking and poor cognitive impairment in children and adolescents. They said this study is the first to conclude that second-hand smoke exposure could lead to dementia and other neurological problems in adults.

For their study, researchers examined saliva samples from nearly 5,000 non-smoking adults over the age of 50. The samples were tested for cotinine, a product of nicotine that can be found in saliva for 25 hours after exposure to second-hand smoke.

The participants were then given neuropsychological tests to assess brain function and cognitive impairment. The tests focused on memory function, numeracy and verbal fluency. Those who scored in the lowest 10 percent were defined as suffering from some level of cognitive impairment.

Heart disease is known to increase the risk of developing dementia and second-hand smoke exposure is known to cause heart disease, which could explain the link between second-hand smoke and cognitive impairment, the study found.

Dr. Mark Eisner of the University of California said that this study and others linking second-hand smoking to impaired childhood cognitive development will hopefully lead to greater public awareness about the dangers of second-hand smoke.

Eisner said he'd like to see this "eventually translate into political action aimed at passing smoke-free legislation in regions of the world where public smoking is still permitted."

SOURCE: Published online on Feb. 12 on the British Medical Journal's Web site


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