(2/4) We looked at 11 established risk factors: less education; hearing loss; hypertension; obesity; smoking; depression; social isolation; physical inactivity; diabetes; alcohol excess; and air pollution.

Using a population attributable fractions approach, adjusted for communality (to account for shared risk factors), we found that:

1️⃣ physical inactivity (8.3%),

2️⃣ hearing loss (7.0%), and

3️⃣ obesity (6.6%)

accounted for the largest proportion of dementia cases.

(3/4) The 11 established risk factors accounted for a greater proportion of dementia in Aboriginal and Torres Strait Islander people (44.9%) than they did in people with European (36.4%) or Asian (33.6%) ancestry.

This reflects greater disadvantage experienced by Aboriginal and Torres Strait Islander people, leading to greater exposure to the risk factors. However, it also means there’s significant scope to improve brain health & reduce dementia incidence if these risk factors can be improved.

(4/4) For people from all ethnic backgrounds, improving physical activity, preventing and treating obesity, and improving hearing could substantially reduce the incidence of future dementia.

This work was led by Rhiann Sue See and Fintan Thompson from the Healthy Ageing Research Team at James Cook University, with Sarah Russell, Rachel Quigley, Adrian Esterman, Linton Harriss, myself, Sean Taylor, Kylie Radford, Dina LoGiudice, Robyn McDermott, Gill Livingston, and Edward Strivens.