Health Desk--- 20 July, 2017: A new international study published in the Lancet said one in three cases of dementia could be prevented if more people looked after their brain health throughout life.
It lists nine key risk factors including lack of education, hearing loss, smoking and physical inactivity.
The study is being presented at the Alzheimer's Association International Conference in London.
By 2050, 131 million people could be living with dementia globally.
There are estimated to be 47 million people with the condition at the moment.
Nine factors that contribute to the risk of dementia
These risk factors - which are described as potentially modifiable - add up to 35%. The other 65% of dementia risk is thought to be potentially non-modifiable.
Lead author Prof Gill Livingston, from University College London, said, "Although dementia is diagnosed in later life, the brain changes usually begin to develop years before".