Like his seven surviving siblings, 76-year-old Claude Timbery is sharp and enjoying life with no sign of dementia. Other than a "pair of dicky knees", he has few health problems and enjoys the weekly "yarn up" at the local Aboriginal community centre.
But Mr Timbery's in-laws weren't as fortunate. Far too many have developed dementia including Alzheimer's. His daughter Alison Timbery said she had a cousin whose mother developed dementia who had been part of the stolen generations: "[My aunt] didn't show any love to them."
New research has found that Indigenous people with high rates of childhood trauma, including those who were forcibly removed from their families such as Alison's aunt, are nearly three times more likely to develop dementia, especially Alzheimer's disease, than others.
Dementia expert Kylie Radford, who led the research published in the American Association for Geriatric Psychiatry, says she hopes the study could go some way to explaining why the rate of dementia in Australia's Indigenous population is three to four times greater than the broader community, and often occurs earlier in life. This rate of dementia is higher than observed in any other population in the world.
As part of the Koori Growing Old Well study, researchers are tracking the health of 336 Aboriginal and Torres Strait Islanders aged 60 to 92 from Sydney, including La Perouse and Campbelltown, and the Mid North Coast.
To determine the link between dementia and their childhoods, participants (including Mr Timbery) were asked to answer questions about their lives before they turned 15.
Called the childhood trauma questionnaire (CTQ), the survey is designed to determine if participants had suffered emotional neglect or abuse or whether their childhoods had been happy and loving.
They were asked if they had ever been hit with a belt or a strap, something more common in previous generations. Other questions included if they or people they knew had been forcibly removed from families, by a mission, government or welfare; if they had moved house frequently or if they or someone they knew had been incarcerated; and if they had suffered childhood head trauma or health problems including otitis media (recurrent severe ear infections).
One in four had experienced high rates of trauma compared with one in 10 in the broader community, said Dr Radford, a clinical neuro-psychologist at Neuroscience Research Australia (NeuRA) and a dementia research fellow with the National Health and Medical Research Council (NHMRC) and the Australian Research Council (ARC).
After controlling for depression and anxiety, both of which increase the risk of dementia, they found a strong independent association between dementia and childhood trauma, said Dr Radford,
"If you are in the top 25 per cent of people - with extreme scores - your likelihood of being diagnosed with dementia is nearly three times higher compared with someone in the bottom 75 per cent, in what we consider to be a fairly normal range," she said.
Dementia in the Indigenous community was widespread and awareness was growing, said Darryl Wright, the chief executive of Campbelltown's Tharawal Aboriginal Corporation and a co-investigator of the project.
"What everyone wants to do is retire quietly and peacefully, that's the aim of life," he said.
But the research showed Aboriginal people were traumatised and paying the price of "colonisation, the stolen generation, slavery, and massacres".
"People don't realise this is all still with Aboriginal people," said Mr Wright. His own grandparents would relive the horror over and over again of the massacre at Appin, where on a moonlit night in April 1816 Aboriginal people were slaughtered.
Some rushed off the precipice over a cliff in despair only to be smashed on the rocks below.
"You can hear the rumbling down below ... generations of screams [coming from where they were] falling down the cliffs where they were pushed," he said, adding that many in his community avoided this location.
One participant in the study scored 117 out of a possible 125, indicating a very extreme level of childhood trauma.
Higher trauma scores were associated with adversity and stress, including living in a city, moving house, forced removal or separation from family as a child, and poor health.
Low education or the death of a parent were not significantly associated with increased trauma. And a large number of siblings in families was associated with low trauma
The finding seems consistent with Mr Timbery's memories of his childhood in La Perouse, a strong Aboriginal community. His father died when he was 12, and a sibling died very young leaving his mother and his remaining siblings to fend for themselves. But he recalled the community rallied to pass the hat when tragedy struck. "Everyone would help - they'd go around the houses getting a collection," said Mr Timbery.
Dr Radford said the good news was that the number of older healthy Aborigines was increasing at a faster rate than any other time.
"They are survivors - and many are ageing well," she said.