A new study suggests that quitting smoking – even in middle age or later – can slow cognitive decline.
While cognitive decline occurs naturally with aging, research suggests that smoking worsens it and can increase the risk of dementia.
Previous research has found that quitting smoking early in life can reduce these effects. Mikaela Bloomberg, epidemiologist at University College London and lead author of the article published this week, says that those who quit the habit early showed cognitive scores comparable to those of people who never smoked.
She wanted to find out if quitting smoking later in life would have a similar impact.
To find out, the research team analyzed data from a survey of more than 9,000 participants aged 40 or older in 12 countries. They paired people who had quit smoking with continuous smokers according to their initial cognitive scores and other characteristics, including sex, age, education level, and country of birth.
The results showed that, for those who had quit smoking, verbal fluency declined at a rate approximately half that of their smoking counterparts. For memory, the decline was reduced by 20%.
“Many older people may think there’s no reason to quit after decades of smoking, but our study suggests that quitting even later in life is linked to slower cognitive decline,” says Bloomberg.
Dr. Neal Benowitz, cardiovascular physician and clinical pharmacologist who has studied the health effects of tobacco, says it’s a significant study, especially for older smokers.
“One of the important problems in tobacco control is that older smokers are not quitting at very high rates like younger smokers,” he says.
Benowitz adds that citing the study in campaigns encouraging older smokers to quit or switch to a non-combustible form of nicotine, such as e-cigarettes or nicotine pouches, could be a good next step.
Smokers have an increased risk of dementia, one of the leading causes of death worldwide. Cigarette smoke exposes the body to high levels of oxidative stress, explains Benowitz. This process damages cells and tissues, including small blood vessels that supply oxygen to the brain, which can result in inflammation.
This affects cardiovascular health and “can cause things like stroke,” says Bloomberg, “and all these things can impact cognitive function because they damage the brain structures that give rise to cognitive function.” She notes that there is some evidence that this may contribute to the risk of dementia as well.
Bloomberg agrees that the study could motivate quitting smoking later in life.
“You would think you need to quit during early to mid-adulthood, and then you’ve missed that kind of critical period for when you can quit. But that just doesn’t seem to be the case here,” she says.
She adds: “It’s never too late to quit.”
Source: npr.org by Aru Nair, Regina G. Barber