Although the study does not directly prove that quitting smoking prevents dementia, it does indicate a clear link between quitting smoking and improved long-term brain health.
The study included more than 32,000 middle-aged and older adults, with an average age of 61, and researchers followed their health for 10 years. Participants included current smokers, former smokers, and people who had never smoked.
The researchers relied on periodic interviews conducted every two years to assess the smoking habits, weight, and general health of the participants, along with tests to measure memory and mental abilities, in addition to using observations from those close to them about behavioral and cognitive changes.
During the study period, 5,868 participants developed dementia. After analyzing the data and taking into account factors such as age, physical activity, and cardiovascular health, it was found that those who quit smoking had a 16% lower risk of developing dementia compared to those who continued to smoke.
The results also showed that the benefits of quitting smoking increase over time, as the risk of developing dementia in those who quit smoking about seven years ago approached the risk level of people who had never smoked.
However, the study also highlighted an important factor related to weight gain after quitting smoking. Those who did not gain a significant amount of weight, or whose weight gain was moderate (no more than five kilograms), maintained the cognitive benefits associated with quitting smoking. In contrast, those who gained 10 kilograms or more after quitting did not show the same benefits.
Dr. Hui Chen, from the School of Medicine at Zhejiang University in Hangzhou, China, said that many people worry about the effects after quitting smoking, such as weight gain and metabolic changes, but the study's findings indicate that quitting smoking remains associated with improved brain function, while maintaining weight may help sustain these benefits.
He added that more studies are needed to understand the role of weight management and lifestyle in enhancing the cognitive benefits of quitting smoking with age.
The researchers pointed out that one of the main limitations of the study was its reliance on information provided by the participants themselves about smoking and weight, which may affect the accuracy of some of the data.
