A male regular smoker has a higher risk of rapid cognitive decline, compared to his counterparts who do not smoke, researchers from University College London, England, reported in Archives of General Psychiatry. The authors add that the evidence has been mounting regarding the link between smoking and dementia in elderly individuals - smoking has been found to push up the total number of patients with dementia around the world.
Séverine Sabia, Ph.D., and team set out to determine what impact smoking might have on men during their transition from middle age to old age. They gathered data from the Whitehall II cohort study, which was based on people who worked in the British Civil Service. They analyzed data on 2,137 females and 5,099 males whose average age at their first cognitive assessment was 56 years.
They specifically looked at six assessments of individuals' smoking status over a 25-year-period, as well as three cognitive assessments which took place over a decade.
The researchers found that:
- Males smokers had a higher risk of accelerated cognitive decline
- Those men who carried on smoking after follow-up had even greater cognitive decline, according to the test results
- Even the regular smokers who had quit during the 10 years before their first cognitive assessment still have a higher-than-average risk of suffering cognitive decline, particularly in executive function. Executive function refers to such cognitive processes as working memory, attention, solving problems, verbal reasoning, mental flexibility, multi-tasking, inhibition, and monitoring of actions.
- Long-term ex-smokers had the same risk of cognitive decline as lifetime non-smokers.
"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."
The same associations were not found in women, and the authors are not sure why. They suggest that perhaps adult males are generally heavier smokers than adult females.
In an Abstract in the same journal, the researchers concluded:
"Compared with never smokers, middle-aged male smokers experienced faster cognitive decline in global cognition and executive function. In ex-smokers with at least a 10-year cessation, there were no adverse effects on cognitive decline."
Written by Christian Nordqvist