A study of almost 10,000 pensioners from Britain and continental Europe has found that smoking habits have an impact on cognitive function, with past or present smokers suffering a markedly faster mental decline.

Participants in the study were assessed for cognitive ability over an average of 30 months under a test known as the Mini-Mental State Examination (MMSE), which includes tasks in comprehension, reading, writing and drawing. Among those who had never smoked, MMSE scores declined by 0.03 points a year, while current smokers dropped by 0.16 points over the same period. Former smokers’ scores were found to decrease by 0.06 points a year, twice the rate of those who had never smoked.

Alewijn Ott, the lead author based at Erasmus Medical Centre in Rotterdam, said that noticeable trends had emerged because of the number of participants, who were all over 65.

The research, published today in Neurology, the scientific journal of the American Academy of Neurology, involved 9,209 men and women, none of whom suffered from dementia. Greater cognitive decline occurred with higher cigarette pack-year exposure, a calculation involving the number of years someone has smoked and the reported average daily number of cigarettes.

Professor Ott said that the findings were significant mainly for the former smokers and not the current smokers, in part due to lower numbers of current smokers in the study because of their higher death rate. The study, conducted in Britain, Denmark, France and the Netherlands, suggests that smoking could affect cognitive function through various mechanisms, including the onset of atherosclerosis and hypertension caused by tobacco use.

Professor Ott said that such conditions, and other effects of smoking, increased the risk of stroke and “silent” brain infarctions. He added: “More in-depth studies are needed to verify if these or other factors are responsible for greater cognitive decline in smokers.”

Amanda Sandford, of the anti-smoking group ASH, said “Given the amount of poisons in cigarette smoke, it would seem logical that it must have some negative impact on brain function.”

Times Recommends

• Madonna and her Guy decide it’s over
• Internet phone calls are jeopardising terror fight
• Red squirrels develop immunity to grey plague