Exposure to second-hand smoke could increase the risk of developing dementia and other forms of cognitive impairment, according to research published on the British Medical Journal website.
A link between active smoking and cognitive impairment has already been established, but findings also suggest that second-hand smoke exposure could be linked to poor cognitive performance in children and adolescents. Now, a large-scale study has concluded that second-hand smoke exposure could lead to dementia and other neurological problems.
Researchers examined saliva samples from almost 5000 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 about 25 hours after exposure to second-hand smoke. Participants also provided a detailed smoking history.
The researchers used established neuropsychological tests to assess brain function and cognitive impairment. Participants whose scores were in the lowest 10 percent were defined as suffering from some level of cognitive impairment.
The link between second-hand smoke and cognitive impairment could be explained by the fact that heart disease increases the risk of developing dementia, and second-hand smoke exposure is known to cause heart disease.