Quitting smoking protects the brain even if you do it after the age of 50: it slows down cognitive decline and could protect against dementia.
Quitting smoking is perhaps the most revolutionary gesture that can be done to protect brain health – even if stopping cigarettes occurs at an advanced age. Research published in Lancet Healthy Longevity observed that giving up smoking is rewarded with a notable slowdown in cognitive decline in subsequent years, and that it could reduce the risk of developing dementia. These benefits also apply to people who quit smoking in their 50s or later in life: the population that usually struggles the most and is least motivated to quit this habit.
Memory and language
Scientists at University College London followed over 9,400 people aged over 40 (and an average age of 58) involved in 3 longitudinal studies underway in 12 countries: this type of research follows the same group of individuals for a long time and collects data several times to monitor the evolution of the parameter being analysed.
Half of the participants had stopped smoking: the answers that these people gave to cognitive tests administered every 2 years were compared with those given by an equal number of participants who had not stopped smoking, but similar in age, sex, level of education and countries of origin.
If in the six years before quitting smoking, memory and verbal fluency (i.e. the way in which spoken language flows regularly and without interruptions) had deteriorated at a similar rate in the two groups of participants, after half of them stopped smoking the decline in these cognitive functions followed different trajectories. In the six years after quitting cigarettes, the rate of memory decline in former smokers was 20 percent slower than in current smokers, and the rate of decline in verbal fluency was halved.
Lasting changes
Even if the analysis was limited to observing a phenomenon, without establishing cause-effect relationships, the results are important because they document long-lasting benefits over time. In the past, several studies had found immediate positive effects on cognitive health after quitting cigarettes, but it was not clear whether these improvements were here to stay.
An antidote to dementia?
Smoking is thought to negatively impact cognitive function because it damages blood vessel walls, causes chronic inflammation, and directly damages brain cells by producing unstable molecules called free radicals.
Since slower cognitive decline is linked to a lower risk of dementia, quitting smoking, even at a “mature” age, could protect the brain from this pathological form of aging, a hypothesis that will need to be investigated further.
