Smoking cessation linked to 16% lower dementia risk, weight gain matters

A longitudinal study of over 32,800 middle‑aged and older adults, published in the journal Neurology, examined the relationship between smoking, weight change and cognitive health over an average of ten years. Participants were 20% current smokers, 36% former smokers and 43% never smokers at baseline. After adjusting for age, activity, cardiovascular health and other factors, those who quit smoking showed a 16% lower risk of developing dementia compared with those who continued smoking.

The protective effect grew with time; about seven years after quitting, former smokers’ dementia risk approached that of never smokers. Weight gain after cessation influenced the benefit: individuals who gained up to five kilograms retained the reduced risk, whereas those who gained ten kilograms or more did not see a measurable advantage. The researchers note that the study is observational, based on self‑reported smoking and weight data, and therefore demonstrates an association rather than a proven causal link.