Dementia risk for people who quit smoking in middle age ‘same as someone who never smoked’

The study comprising 9,436 people in England, America and 10 other European countries showed that those who quit smoking can reduce their cognitive decline dramatically. Photograph: Johanna Parkin/The Guardian

People who stop smoking in middle age can reduce their cognitive decline so dramatically that within 10 years their chances of developing dementia are the same as someone who has never smoked, research has found.

Kicking the habit halves the rate of decline in verbal fluency and slows the loss of memory by 20%, according to a study of 9,436 people in England, the US and 10 other European countries.