Giving enough activity for the brain and eating a healthy diet is the best way to offset dementia , according to a new study.
While the exact cause of dementia is still unknown, several modifiable risk factors have already been identified.
These include vascular risk factors (heart disease, stroke, high blood pressure, obesity, diabetes, and high cholesterol), a history of depression, diet, alcohol consumption, and education level.
Based on this knowledge, a team of researchers based in France and the UK estimated which of these risk factors might be most effective in reducing the future burden of dementia, should no effective treatment be found.
Their analysis involved 1,433 healthy people aged over 65 years living in the south of France and recruited between 1999 and 2001. Participants underwent cognitive testing at the start of the study and again at two, four and seven years. A reading test (the Neale score) was also used as an indicator of lifetime intelligence.
Medical history and information on measures such as height, weight, education level, monthly income, mobility, dietary habits, alcohol consumption, and tobacco use was obtained. An individual's genetic risk of dementia was also measured: although it's not a factor that can be changed it served as a useful benchmark for dementia risk.
Results showed that eliminating depression and diabetes and increasing fruit and vegetable consumption were estimated to lead to an overall 21 percent reduction in new cases of dementia, with depression making the greatest contribution (just over 10 percent). However, the researchers point out that the direct (causal) relationship between depression and dementia remains unclear.
Increasing education would also lead to an estimated 18 percent reduction in new cases of dementia across the general population over the next seven years.
By contrast, eliminating the principal known genetic risk factor from the general population would lead only to a 7 percent reduction in the number of new cases over the next seven years.
The study has been published online in the British Medical Journal.