A new study from University College London (UCL) shows that quitting smoking—even in your 50s or later—can help slow down memory loss and mental decline that often come with aging.
The study, published in The Lancet Healthy Longevity, looked at data from 9,436 adults aged 40 and older across 12 countries. On average, participants were 58 years old.
Researchers compared people who quit smoking with those who continued smoking. They measured their memory and verbal fluency—how well they could remember words and speak quickly—over time.
In the six years after quitting, former smokers showed a slower decline in thinking skills compared to those who kept smoking. People who quit had a 20% slower decline in memory and a 50% slower decline in verbal fluency.
This matters because slower cognitive decline is linked to a lower risk of dementia. So, quitting smoking in midlife could be a way to help prevent the disease. More research is still needed to confirm the link, but the findings are promising.
Lead author Dr. Mikaela Bloomberg explained that quitting smoking has long been known to improve physical health, even later in life. Now it seems it may also help protect brain health.
She emphasized that many people in their 50s or older are less likely to try quitting, even though they face more health risks from smoking. This new evidence could be a powerful reason for them to consider quitting.
Co-author Professor Andrew Steptoe added that this study adds to earlier findings that stopping smoking might help prevent dementia. While the study doesn’t prove that quitting smoking directly prevents dementia, the slower mental decline in former smokers is a good sign.
The study used data from long-term research projects in England, the US, and 10 other European countries. Participants took part in surveys every two years.
Researchers compared 4,700 people who had quit smoking with a similar group of 4,700 people who kept smoking. Both groups were alike in age, education, country of birth, and their thinking abilities before quitting began.
Before quitting, both groups showed similar declines in memory and thinking speed. But after quitting, the people who stopped smoking began to decline more slowly. Each year, those who quit had three to four months less memory loss and six months less loss in verbal fluency than those who kept smoking.
The reason smoking harms brain health is likely due to several factors. It damages blood vessels, which affects how oxygen reaches the brain. It also causes chronic inflammation and increases levels of harmful molecules called free radicals, which can damage brain cells over time.
While this study was observational and cannot prove cause and effect, it supports earlier research showing that people who quit smoking have similar cognitive health to people who never smoked—especially if they quit during midlife.
Overall, this study offers new motivation for people in their 50s or older to quit smoking. It shows that it’s never too late to benefit from quitting—not just for your heart and lungs, but also for your brain.
If you care about dementia, please read studies about Common drug for constipation is linked to higher dementia risk and findings of Scientists find link between heartburn drugs and increased dementia risk.
For more about dementia, please read studies about Scientists find a drug related to Viagra may help treat vascular dementia and findings of link between body inflammation and dementia risk.
The study is published in The Lancet Healthy Longevity.
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