What does smoking do to your brain as you age?
Smoking accelerates brain ageing and increases the risk of dementia. Quitting smoking is one of the best-supported steps you can take to keep your brain healthy for as long as possible.
Smoking increases the risk of dementia. Large global burden-of-disease studies (GBD 2019) recognise smoking as a modifiable risk factor for dementia, alongside high blood sugar and excess weight. Projections show that the number of people living with dementia worldwide will rise from 57 million in 2019 to 153 million in 2050, and smoking is one of the factors driving that increase.
On MRI scans, the brains of smokers look older than they actually are. A large British study of more than 31,000 participants showed that people with diabetes who also smoked had the most accelerated brain ageing. Those who quit smoking, drank less alcohol and exercised more had significantly less of that extra brain ageing. Smoking therefore makes the brain more vulnerable, especially in combination with other risk factors.
There is one notable exception: Parkinson's disease. Multiple studies show an inverse association. Declining smoking rates in the population are linked to a higher burden of Parkinson's disease. Researchers cite this as one of the drivers behind the expected 'Parkinson's pandemic', with the number of patients worldwide projected to reach 17 million by 2040. This association is at present purely a statistical one, not evidence that smoking actually prevents Parkinson's disease. The harmful effects of smoking outweigh this paradoxical signal.
Quitting smoking is concretely supported as a brain-protective measure. Multiple large health organisations recommend stopping smoking as one of the most important steps against cognitive decline and dementia. Research drawing on epidemiological data, animal experiments and intervention studies consistently points in the same direction: those who quit protect their brains.
Based on four claims from international epidemiological research, including GBD 2019 data and the UK Biobank (n>31,000). No randomised trials are available for most outcomes; causal relationships are associative or probably causal. The Parkinson's association is exclusively associative.
What does high cholesterol do to your brain as you age?
High cholesterol in middle age likely increases the risk of dementia, but at older ages the relationship is less clear and cholesterol-lowering drugs have not been proven effective for the brain. Stable cholesterol appears wiser than strongly fluctuating values; discuss your risk profile with your doctor if you are concerned.
Do your brains really shrink as you get older?
Your brain does indeed shrink with age, particularly in areas involved in memory and planning. High blood pressure accelerates that process, while exercise and cognitive effort strengthen your brain's compensatory activity.
What does air pollution do to your brain in the long term?
Long-term exposure to air pollution, and fine particulate matter in particular, is associated with an increased risk of dementia and faster memory decline. The associations have been demonstrated in multiple human studies, but a direct cause-and-effect relationship has not yet been conclusively proven.
What can I do to keep my brain healthy as I age?
Combining more exercise with staying mentally active and eating a diet low in sugar and higher in omega-3 fatty acids currently gives you the best chance of a healthy brain. Spermidine and new insights into how the brain cleans itself are, for now, only interesting to follow.
Why does your memory work less well as you get older?
Memory loss with ageing is a normal biological process with multiple clearly demonstrated causes, but you can slow it down: regular exercise and mental activity have the strongest evidence base.
Does your brain age faster than the rest of your body?
Whether your brain ages faster than the rest of your body varies from person to person, but the consequences are significant: a biologically old brain increases the risk of Alzheimer's more than threefold. Keep an eye on your blood pressure, sleep and lifestyle, as these have the most demonstrable influence on brain ageing.