Findings of a report published Online First in the Archives of General Psychiatry, one of the JAMA/Archives journals shows that men who smoke seem to be linked with a more rapid cognitive decline.

According to background information, smoking is more and more renown as a risk factor for dementia in the elderly. In 2010, the number of dementia diagnoses around the world was estimated at 36 million with numbers increasing and predicted to double every 20 years.

Séverine Sabia, Ph.D., of the University College London and her team assessed the link between smoking history and cognitive decline during the transition from midlife to old age by obtaining data from 5,099 men and 2,137 women from the Whitehall II cohort study, which is based on employees of the British Civil Service. The average age of the participants was 56 years at the first cognitive assessment.

In their new study, the researchers evaluated data from six assessments of smoking status over a 25 year-duration and three cognitive assessments over 10 years and established four major findings, which indicate that men who smoked are linked to a more rapid cognitive decline, and that those who continued smoking over the follow-up period had a bigger decline in all cognitive tests.

They also observed that those who quit smoking in the 10 years before the first cognitive measure were still at risk of greater cognitive decline, in particular in executive function, an overall term for various complex cognitive processes involved in achieving a particular goal, whereas there was no faster cognitive decline in long-term ex-smokers.

The researchers conclude:

“Finally, our results show that the association between smoking and cognition, particularly at older ages, is likely to be underestimated owing to higher risk of death and dropout among smokers.”

They also observed no link between smoking and cognitive decline in women, even though the underlying reasons remain unclear, and hypothesize that one explanation for the sex difference could be that men smoke greater quantities of tobacco.

Written by Petra Rattue