Smoking is likely to be one of the main lifestyle factors that lead to cognitive decline later in life, according to a new study in Nature Communications. The study, led by UCL researchers, followed 32,000 participants from 14 European countries for over ten years.
The team from UCL investigated how smoking and other health-related factors, such as physical activity and alcohol consumption, affect cognitive decline in older adults. Cognitive function was assessed as the participants completed memory and verbal fluency tests. Participants were grouped into groups based on whether they smoked, whether they did physical activity at least once per week, whether they saw friends and family at least weekly, and whether they drank more or less than two alcoholic drinks per day (men) or one drink per day (women).
Results show that cognitive decline was faster in participants who smoked compared to those who didn’t smoke. Smoking lifestyles had cognitive scores that declined up to 85% more over ten years than non-smoking lifestyles. The only exception was if smokers had a healthy lifestyle in all other areas, and they exercised regularly, drank alcohol in moderation, and socialized regularly. This group had a rate of cognitive decline similar to non-smokers.
“Our study is observational so cannot definitively establish cause and effect, but it suggests smoking might be a particularly important factor influencing the rate of cognitive ageing. Previous evidence suggests individuals who engage in more healthy behaviours have slower cognitive decline; however, it was unclear whether all behaviours contributed equally to cognitive decline, or if there were specific behaviours driving these results,” said lead author Dr Mikaela Bloomberg from UCL Behavioural Science & Health.“Our findings suggest that among the healthy behaviours we examined, not smoking may be among the most important in terms of maintaining cognitive function. For people who aren’t able to stop smoking, our results suggest that engaging in other healthy behaviours such as regular exercise, moderate alcohol consumption and being socially active may help offset adverse cognitive effects associated with smoking.”
Bloomberg, M., Muniz-Terrera, G., Brocklebank, L. et al. Healthy lifestyle and cognitive decline in middle-aged and older adults residing in 14 European countries. Nat Commun15, 5003 (2024). https://doi.org/10.1038/s41467-024-49262-5