Smoking may Blow up Your Memory: Study

Smoking has long been known to cause respiratory problems and heart disorders but French researchers have recently spotted a link between smoking and poor memory in middle-aged adults.

While smoking is a familiar health hazard, questions have often been raised on its effect on dementia, the study authors said.

"Dementia is rare among middle-aged people, but cognitive function at this age in closely related to dementia," said lead researcher Severine Sabia, of the Institut National de la Sante et de la Recherche Medicale in Villejuif, France. "Our results show that smoking is associated with poorer cognition and decline over five years.”

"Another interesting finding," Sabia added, "was that ex-smokers improved their other health behaviors, and among them there was little residual adverse effect of smoking on cognition."

The study was published in the June 9 issue of the Archives of Internal Medicine journal.

It involved 10,308 British civil servants who were aged between 35 and 55 and enrolled in the Whitehall II study between 1985 and 1988.

Smoking habits of the participants were assessed at the beginning of the study and again between 1997 and 1999. Then from 1997 to1999, researchers conducted tests of memory, reasoning, and vocabulary and verbal fluency among 5,388 participants, 4,659 of whom were re-tested after five years.

The first round of cognitive testing indicated that people who smoked ranked in the lowest 20 percent of all those examined, compared with people who had never smoked. However, ex-smokers were 30 percent less likely to have poor vocabulary and low verbal frequency scores than current smokers.

"Smoking is associated with poorer cognitive function in midlife," Sabia said. "However, 10 years after smoking cessation, there is little adverse effect of smoking on cognition."

Ex-smokers were found to have healthier habits as they drank less alcohol, exercised habitually and had more fruits and vegetables in their diet, as compared with current smokers.

Giving up smoking in midlife usually transforms into enhancement of other health behaviors, said the researchers.

“Our results based on a large prospective cohort study of middle-aged British civil servants suggest that the association between smoking and cognition, even in late midlife, could be underestimated because of higher risk of death and non-participation in cognitive tests among smokers,” said the researchers.

Public Health messages on smoking have shown significant results and the researchers emphasized that they must continue to target smokers of all age-groups.