Accelerated decline in cognitive reasoning and memory is more advanced in smokers, according to researchers and University College London (UCL).
Dr Gareth Hagger-Johnson, research associate at UCL, said:
[One] of our studies at UCL show [decline] to be nearly 38% faster in persistent male smokers compared to non-smokers.
The decline in the brain's cognitive powers is naturally seen with ageing but there are a number of identifiable risk factors, including smoking and heavy alcohol consumption, which can be associated with an accelerated rate of decline.
More top news
Madonna says she still cannot bring herself to watch footage of the moment she fell on stage while performing at the Brit Awards.
Ed Miliband has pledged to give zero-hours workers the right to convert their contract into a regular job after three months.
More than 100 leaders have declared their support for a Conservative-led government, warning a Labour would "put the recovery at risk".