受動喫煙は認知症他の遠因になる？

受動喫煙は発がん等呼吸器系統の疾患以外にも問題があるのですね。

New research suggests exposure to second-hand smoke could increase the risk of developing dementia and other forms of cognitive impairment.

The research, published in the British Medical Journal, highlighted a 44 percent increase in risk of cognitive impairment when exposed to high levels of second-hand smoke.

Previous studies identified active smoking as a risk factor for cognitive impairment and dementia.

However, this is the first large-scale study to conclude that second-hand smoke exposure could lead to dementia and other neurological problems in adults. (Previous findings suggested that second-hand smoke exposure could impair cognitive development in children and adolescents.)

The research, led by Dr. David Llewellyn, used saliva samples from nearly 5000 non-smoking adults over the age of 50. By measuring levels of cotinine (a byproduct of nicotine) in their saliva and taking a detailed smoking history, the researchers were able to assess levels of exposure to second-hand smoke.

ということです。ただ、なぜ認知症他の疾患に結びつくかというところで、心臓病や心臓発作を挙げており、直接受動喫煙で脳に変調を来すという風には考えられていないようです。

The authors proposed a number of possible explanations for why exposure to second-hand smoke may increase the odds of dementia, including an increased risk of heart disease and stroke which are known to increase the risk of cognitive impairment and dementia.

http://psychcentral.com/news/2009/02/13/second-hand-smoke-may-cause-mental-impairment/4102.html