TOPLINE:

Memory and verbal fluency declined at a significantly slower pace in people who quit smoking in mid‑to-late life compared to those who continued smoking, with cognitive benefits from quitting observed regardless of specific age at cessation, a new study showed.

METHODOLOGY:

• Researchers conducted a secondary analysis of data from three nationally representative cohort studies across 11 European countries and the US (2002-2020).
• Among the more than 9000 participants aged 40-89 years, half were previous smokers (mean age, 58 years; 52% women) and the other half were matched individuals who continued smoking (mean age, 58 years; 52% women).
• The median follow-up was 8 years for smokers who quit and 6 years for those who continued smoking. Results focused on 6‑year windows both before and after the age at reported cessation.
• At each interview, memory was assessed using immediate and delayed recall tasks, and fluency was examined using the animal-naming task.

TAKEAWAY:

• In the pre-cessation period, both groups showed comparable cognitive decline (difference in memory decline, -0.03 SD; difference in fluency decline, -0.01 SD).
• Following smoking cessation, those who quit had a slower cognitive decline compared to those who continued (difference in memory decline,.05 SD; P = .04; difference in fluency decline,.05 SD; P = .03).
• The memory trajectory improved for smokers who quit compared to continuing smokers, with a difference-in-difference of.08 SD (P = .03). The difference‑in‑difference for fluency was.06 SD, but the improvement did not reach statistical significance.
• Cognitive results were similar for all ages at time of smoking cessation.

IN PRACTICE:

"This finding is especially important because middle-aged and older smokers are less likely to try to quit than younger groups, yet they disproportionately experience the harms of smoking. Evidence that quitting may support cognitive health could offer new compelling motivation for this group to try and quit smoking," lead author Mikaela Bloomberg, PhD, University College London, London, England, said in a press release.

SOURCE:

The study was published online on October 13 in The Lancet Healthy Longevity.

LIMITATIONS:

Unmeasured confounding may have affected causality assumptions, and the decision to quit smoking may depend on cognitive function. Between-cohort differences in wording of the smoking question could have affected the ability to capture occasional smokers. The included participants were somewhat healthier than excluded participants, potentially affecting generalizability. Additionally, the study probably included individuals whose health was less affected by smoking compared to average smokers.

DISCLOSURES:

The study was funded by the National Institute on Aging and National Institute for Health and Care Research. One investigator reported receiving funding from Cancer Research UK and royalties from Wiley. The others reported no relevant financial relationships. 

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.