How Smoking Harms your IQ in Old Age

Lawrence - We looked at archives of peoples' IQ tests from 1932 and 1947. We used this childhood data to look at lifelong changes in mental ability. These people are now old -from 63 to 84 - so we're getting a spectrum of change.

Chris - What have you found?

Lawrence - We have found that some of the decline in mental ability with age is due to genetic factors. As far as environmental factors are concerned, we found that smoking advances ageing in the brain by one to two years. This is contrary to people who say that smoking is good for them and that it improves their vigilance and attention.

Chris - Why is there damage to the brain?

Lawrence - I think there are two possible reasons that the brain is damaged. Firstly, the efficiency of the lungs is impaired, meaning that less oxygen can get to the brain. Secondly, the oxidative stress caused by smoking might extend further than just the lungs, and affect the brain [leading to directly to damage of nerve cells, and to damage to blood vessels in the brain, affecting blood flow to the brain].