article_snippet.sent: Quite why this happens is not understood, but this may be related to the impact the condition has on the brain.
article_snippet.sent: Smoking: Many studies have found that even occasional smoking can impact on the brain.
article_snippet.sent: One study, from King's College London, analysed 8,000 over-50s and found that smokers performed worst in memory tests, learning ability and reasoning.
article_snippet.sent: Why this happens is thought to be linked to the fact that smoking reduces the amount of oxygen that reaches the brain.
article_snippet.sent: Those who have smoked have also been shown to have greater overall shrinkage of the brain.
article_snippet.sent: Not 'using it': When someone is diagnosed with dementia, Those who have smoked often start to withdraw from Those who have smoked normal hobbies and activities.