Smoking may increase the risk of dementia and cognitive decline by undermining lung function and increasing the likelihood of respiratory and cardiovascular disease.

Researchers analysed data from 136,018 people 45 years and older. Of these, 11 per cent reported subjective cognitive decline (SCD), which may be an early sign of Alzheimer’s disease and other dementias.

Current tobacco smokers were 87 per cent more likely to report SCD than never smokers. Those who quit more than a year and less than 10 years previously were 47 per cent more likely to experience SCD. Former smokers who quit at least 10 years previously were 11 per cent more likely to report SCD.

“The association we saw was most significant in the 45-59 age group, suggesting that quitting at that stage of life may have a benefit for cognitive health,” says senior author Dr Jeffrey Wing, assistant professor of epidemiology at Ohio State’s College of Public Health.

“A similar difference wasn’t found in the oldest group in the study, which could mean that quitting earlier affords people greater benefits.” (Journal of Alzheimer’s Disease DOI 10.3233/JAD-220501)