Dr Louise Lavrencic

Indigenous Australians have some of the highest rates of dementia in the world, and new research shows for the first time that this applies to those living in urban areas as well as regional and remote Australia.

Researchers from Neuroscience Research Australia (NeuRA) and the University of New South Wales, Sydney, analysed dementia incidence rates in a prospective study of 155 urban-resident Aboriginal Australians and Torres Strait Islander people between 60-86 years of age (average age 66) .

During a follow up for an average of six years, 16 people developed dementia, representing an age-standardised rate of 36 per 1000 person-years. Over the same period a further 20 people developed mild cognitive impairment

Older age (OR 2.29), male sex (OR 4.14), unskilled work history (OR 5.09), polypharmacy (OR 3.11, 1.17-8.28), were positively associated with incident MCI/dementia, while and past smoking (OR 0.24) was negatively associated with dementia in the final model.

The researchers noted that a higher frequency of the APOE e4 gene variant was associated with a four-fold higher risk of Alzheimer’s disease, and the rate among participants was 24% compared to average global estimates of 14% among white populations.

Published in Neurology, the results added to previous studies showing that Indigenous Australians living in remote areas of the country are disproportionately affected by dementia, with rates approximately double those of non-Indigenous people.

“These findings provide the first evidence for higher dementia incidence in Aboriginal Australians from urban areas, where the majority of Aboriginal people reside,” the researchers said.

“Given that the majority of Aboriginal and Torres Strait Islander peoples now live in urban areas, these results are critically important,” said study lead author Dr Louise Lavrencic (PhD).

“Aboriginal Australians have among the highest rates of dementia in the world, so we looked at some of the potential risk factors that may be facing this population. While the study was not designed to examine these factors, the ongoing effects of colonisation, systemic racism, and the resulting social and health disparities across Aboriginal Australian communities likely contribute to these higher rates of dementia,” she said.

Larger studies are needed to look at these effects and identify culturally appropriate and effective dementia risk reduction strategies, she added.