Can you prevent dementia with your lifestyle?

Roughly one third of all dementia cases is linked to factors you can influence yourself. That sounds hopeful, but it also means that two thirds are determined by age and genetic predisposition, things you cannot change. Dementia cannot therefore be prevented entirely, though it may be possible to delay its onset or make it less likely.

The largest modifiable risk increases come from a handful of concrete factors. Smoking is associated with nearly twice the risk of dementia. Uncontrolled high blood pressure carries a similarly elevated risk. Diabetes has even been linked to more than twice the risk. These are not small effects, and the good news is that you can act on all three, though current studies do not prove a direct causal relationship.

Exercise demonstrably helps. Both aerobic training and strength training are associated with a lower risk of cognitive decline. Older adults who are regularly active more often retain their cognitive abilities. How large the effect is exactly is not yet known. Social engagement also plays a role: living alone or being socially isolated was associated with more than 2.5 times the risk of dementia in large observational studies. That is a strong association, though it has not been proven that social interventions actually reduce the risk.

The Finnish FINGER study combined nutrition, exercise, cognitive stimulation and blood pressure control in a single programme, and found a measurable cognitive improvement in older adults with an elevated risk of dementia. Two other large studies found no effect in the overall group, but did find one among participants with additional risk factors. This suggests that a combined approach is most meaningful for people who already have a higher risk, not necessarily for everyone.

For diet, the results are mixed. The Mediterranean eating pattern is often described as protective, but the studies partly contradict one another. There is currently no single diet or supplement that has been proven to prevent dementia. More years of education and sustained mental stimulation are consistently linked to a lower risk, presumably because a better-trained brain can compensate for damage for longer.