A new study published in Neurology has found that quitting smoking is associated with a 16% lower risk of developing dementia compared to continuing smoking, according to the research.
The study, which followed 32,802 U.S. adults aged 50 and older for a median of nearly 10 years, analyzed smoking habits, weight changes, and cognitive health outcomes, according to the report. [1][2] The cognitive benefits increased with longer time since quitting, approaching the risk level of never-smokers after about seven years of cessation, researchers said.
Lead study author Hui Chen of Zhejiang University School of Medicine stated that "the benefits appeared stronger with longer time since quitting," as reported in the study. [4] The findings suggest that the protective effect is dose-dependent: the longer a person remains smoke-free, the lower their dementia risk becomes.
Study Design and Methodology
Data came from the Health and Retirement Study, a large-scale longitudinal survey conducted by the University of Michigan every two years from 1995 to 2020, according to the report. [9] Participants completed interviews every two years about smoking habits, body weight, lifestyle behaviors, and medical history. Researchers categorized participants as current smokers, former smokers, or never-smokers, and tracked those who quit during the study period.
Cognitive assessments included tests of word recall, counting backward, and serial subtraction, officials said. The study accounted for potential confounders such as age, sex, education, and other lifestyle factors. The analysis included 32,802 adults who did not have dementia at baseline, with nearly 6,000 participants developing dementia by the end of the follow-up period, according to the research. [5]
Effect of Weight Gain After Quitting
Participants who gained little or no weight after quitting showed the greatest cognitive benefits, the study found. Those who gained up to about 11 pounds still had a significantly lower dementia risk compared to those who continued smoking. However, gains exceeding 22 pounds appeared to eliminate the cognitive advantage, according to the report. [6][7]
Hui Chen said that "some weight gain after quitting is common and should not discourage cessation," but added that "preventing excessive weight gain may help preserve the long-term brain-health benefits of quitting." The study noted that smoking likely affects the brain through multiple pathways, including vascular damage, inflammation, and oxidative stress. [4] These mechanisms are consistent with broader evidence that metabolic health factors such as obesity and high blood pressure directly increase dementia risk, as noted in related research. [8]
Expert Commentary on Findings
Dung Trinh, an internist at MemorialCare Medical Group and chief medical officer of the Healthy Brain Clinic, said the findings reinforce the importance of pairing smoking cessation with healthy weight management. "The practical takeaway is clear: quit smoking, stay quit, and pair cessation with healthy weight and metabolic management," Trinh stated. [7]
Anoop Singh, a board-certified psychiatrist from Mindpath Health, emphasized that concerns about weight gain should not deter people from quitting. "Some weight gain can happen and should not be seen as failure," Singh said. [7]
Both experts noted that smoking cessation likely benefits brain health through reduced vascular damage, inflammation, and oxidative stress. [10] These pathways are part of a broader lifestyle approach to cognitive preservation that includes exercise, diet, and stress management, according to the literature. [11] Singh recommended combining cessation with "regular movement, good sleep, stress management, balanced meals, and appropriate medical or behavioral support." [7]
Conclusion and Implications
The study adds to evidence that quitting smoking may protect cognitive function over the long term. Researchers and clinicians advised that smoking cessation remains the key goal, and that modest weight gain should not discourage attempts to quit. [7] The findings align with prior research showing that smoking nearly doubles the risk of Alzheimer’s disease, making cessation a critical intervention. [3]
Further research is needed to understand the mechanisms linking smoking, weight change, and dementia risk. Clinicians interviewed for this report recommended that patients who quit smoking be supported with dietary guidance and physical activity to prevent excessive weight gain. The overall message from the study, according to the authors, is that quitting smoking should remain the priority for reducing dementia risk. [4]
References
- Brain & Life. "Quitting Smoking Linked to Lower Dementia Risk." May 21, 2026.
- Newswise. "Quitting Smoking Associated with Lower Dementia Risk." May 20, 2026.
- PMC. "Smoking cessation and Alzheimer's disease: facts, fallacies..."
- Neuroscience News. "Healthy Weight and Quitting Smoking Reduce Dementia Risk."
- MedLink. "Quitting smoking associated with lower dementia risk." May 20, 2026.
- U.S. News. "Quitting Smoking Might Lower Your Dementia Risk." May 22, 2026.
- Medical Xpress. "Quitting smoking associated with lower dementia risk, but weight gain..."
- NaturalNews.com. "Higher BMI and high blood pressure directly linked to increased risk of vascular dementia, study finds." May 4, 2026.
- NaturalNews.com. "Long-Term High BMI Linked to Faster Cognitive Decline, 24-Year Study Finds." May 11, 2026.
- Bottom Line Personal. "Bottom Line year book 2006."
- Gary Small. "The Alzheimers prevention program keep your brain healthy for the rest of your life."
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