Scientists Pinpoint Key Lifestyle Factor Linked to Cognitive Decline Among Older Adults

A decade-long study of 32,000 older Europeans has found that smoking significantly speeds up cognitive decline, up to 85% faster compared to non-smokers.

But there’s hope: smokers who maintain other healthy habits like regular exercise, moderate drinking, and strong social connections experience similar brain aging rates as non-smokers. The research highlights that while multiple behaviors matter for brain health, smoking may be the most damaging of all.

Smoking and Cognitive Decline: A Strong Link Emerges

A major study suggests that smoking could be one of the most powerful lifestyle habits affecting how quickly our thinking skills decline with age. The research, led by scientists at University College London (UCL), highlights smoking as a key factor that may accelerate cognitive aging in older adults.

Published in the journal Nature Communications, the study looked at data from more than 32,000 people aged 50 and older across 14 European countries. These participants were followed for a decade, allowing researchers to track long-term patterns in brain health and behavior.

Lifestyle Factors and Cognitive Testing

The team wanted to understand how different lifestyle choices might influence the rate of mental decline. They focused on people who were cognitively healthy at the start of the study and looked at four main behaviors: smoking, physical activity, alcohol consumption, and social connection.

To measure brain function, participants took tests assessing memory and verbal fluency. Researchers grouped them based on their habits, such as whether they smoked, exercised regularly, stayed socially active, and drank alcohol moderately.

Smokers Show Faster Mental Decline

The results were striking. People who smoked experienced faster cognitive decline than those who didn’t, regardless of their other habits. In fact, smoking was associated with cognitive scores that declined up to 85 percent more over 10 years compared to non-smokers.

However, there was one important exception. Smokers who exercised, stayed socially engaged, and drank alcohol in moderation saw much slower declines. Their brain aging was similar to that of non-smokers, suggesting that a healthy lifestyle can help counteract some of the damage.

Not Smoking May Be the Most Crucial Habit

Lead author Dr. Mikaela Bloomberg (UCL Behavioural Science & Health) said: “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.

“Our findings suggest that among the healthy behaviours we examined, not smoking may be among the most important in terms of maintaining cognitive function.

Staying Active and Social Helps, Even for Smokers

“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.”

The researchers accounted for a range of factors that might have influenced the findings, including age, gender, country, education, wealth, and chronic conditions.

Reference: “Healthy lifestyle and cognitive decline in middle-aged and older adults residing in 14 European countries” by Mikaela Bloomberg, Graciela Muniz-Terrera, Laura Brocklebank and Andrew Steptoe, 27 June 2024, Nature Communications.
DOI: 10.1038/s41467-024-49262-5

The team used data from the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE). ELSA is funded by the National Institute on Aging and by UK Government departments coordinated by the National Institute for Health and Care Research (NIHR). SHARE receives funding from the European Union. Study authors received funding from the Economic and Social Research Council.

A version of this article was originally published in September 2024.

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