A major new study has found that quitting smoking may significantly reduce the risk of dementia, adding another compelling reason for smokers to kick the habit.
Researchers discovered that individuals who stopped smoking had a 16% lower risk of developing dementia compared with those who continued smoking, while also experiencing a slower rate of cognitive decline over time.
The findings, published in the medical journal Neurology, are based on data from more than 32,000 adults in the United States who were tracked for up to 25 years.
The research provides fresh insight into the long-term impact of smoking cessation on brain health and highlights the importance of maintaining a healthy lifestyle after quitting.
The study analyzed information from the Health and Retirement Study, a large national project involving adults aged 50 and older.
Participants, all free from dementia at the start of the research, were monitored between 1995 and 2020.
Every two years, they reported details about their smoking habits, body weight, lifestyle choices, and medical history.
Researchers categorized participants as current smokers, former smokers, or never-smokers.
Cognitive performance was assessed through tests measuring memory, attention, and mathematical skills, including word recall and serial subtraction exercises.
By the end of the study period, nearly 6,000 participants had developed dementia. However, those who quit smoking during the study showed a notably lower risk of developing the condition compared with persistent smokers.
Individuals who had already quit before the study began, as well as those who had never smoked, also demonstrated lower dementia rates.
One of the most striking findings was that the protective effect of smoking cessation appeared to strengthen over time.
Dementia risk steadily declined the longer participants remained smoke-free, approaching the risk levels of never-smokers after approximately seven years without cigarettes.
Lead researcher Hui Chen said the results reinforce the importance of smoking cessation for maintaining cognitive health later in life.
According to Chen, adopting additional healthy habits such as regular physical activity, balanced nutrition, and effective management of cardiovascular and metabolic conditions can further support brain health.
The study also explored how weight gain after quitting smoking influenced cognitive outcomes. Weight gain is a common concern among people attempting to quit, but the findings suggest moderation is key.
Participants who gained little or no weight after quitting experienced the strongest cognitive benefits.
Even those who gained up to 11 pounds maintained a significantly lower dementia risk and slower cognitive decline than people who continued smoking.
However, individuals who gained more than 22 pounds after quitting did not appear to receive the same cognitive advantages.
Despite this observation, researchers emphasized that concerns about weight gain should not discourage smoking cessation.
Chen noted that quitting smoking remains the priority, while preventing excessive weight gain may help preserve the long-term benefits for brain health.
Medical experts not involved in the study welcomed the findings. Dung Trinh said the research underscores the value of pairing smoking cessation with healthy weight management and metabolic health strategies.
Similarly, Anoop Singh described the study as offering a hopeful message, showing that quitting smoking may protect not only the heart and lungs but also cognitive function.
Scientists believe smoking may contribute to dementia through several biological mechanisms, including inflammation, oxidative stress, and damage to blood vessels that supply the brain.
As smoking rates continue to decline across the United States, the latest findings provide further evidence that giving up cigarettes can deliver lasting benefits, potentially helping people preserve their memory and cognitive abilities well into old age.
