American researchers analysed health data from 24,000 patients living with Alzheimer’s, the most common form of dementia.

Through the analysis, they have identified four pathways to developing the disease.

Researchers found more than a quarter of patients had conditions like depression, brain dysfunction illnesses, mild cognitive impairment and heart disease before they were diagnosed.

The more of those factors, the more likely patients were to develop dementia.

Researchers said this could help identify people more at risk and assist with early diagnosis and intervention. 

Currently there are more than 433,000 Aussies living with dementia but that number is expected to almost double by 2054.