Tackling poverty is the single most important thing New Zealand can do to reduce the number of people with dementia, says University of Auckland’s Dr Etuini Ma’u.
Modelling in Ma’u’s latest research shows if everyone lived in the same wealthy environments as the top 20 percent of New Zealanders, dementia rates would drop by about 19 percent over 30 years.
His research shows a 50 percent higher risk of dementia among people living in the most deprived parts of New Zealand, compared with those in the most affluent areas.
Dementia risk increases across every ethnic group as deprivation rises, says Ma’u, who is a senior lecturer in psychological medicine and a Te Whatu Ora psychiatrist for older people.
Rates of dementia are about 50 percent higher among Māori and Pacific people aged over 60 than among European and Asian New Zealanders of the same age, he says.
The underlying driver of that high dementia rate is poverty. About 35 percent of Māori and Pacific people live in the poorest parts of New Zealand, says Ma’u, who is of Tongan descent.
“Dementia risk isn’t driven by ethnicity – it’s driven by deprivation.
“Māori and Pacific people living in affluent areas have a lower risk of dementia and Europeans living in areas with high deprivation are at higher risk of dementia,” he says.
In 2024, the Lancet published research identifying 14 risk factors for dementia.
Some factors can lead to damage to the brain, such as smoking, obesity, physical inactivity, diabetes, excessive alcohol consumption, hypertension, traumatic brain injury, high LDL cholesterol, and air pollution.
Other risk factors reduce brain stimulation. These include social isolation, untreated vision loss, hearing loss, depression, and less education.
The Lancet stated that dementia could be reduced by up to 45 percent if these 14 risk factors were eliminated.
“Dementia is the end result of incremental and cumulative damage to the brain over a lifetime.
“We think of it as a disease that affects older people, but that’s just when the brain can no longer cope with all the changes sustained over the preceding decades.”
Ma’u says people in poorer communities have higher rates of many of these risk factors.
People living in poorer areas are more likely to be surrounded by businesses selling unhealthy products, such as alcohol, tobacco, vapes, and fast food, that increase their risk of developing dementia, he says.
They also have less access to parks and cycleways that make it easier to exercise regularly.
“We’re all the product of our environment. Where we work, live and play influences our daily behaviours and our ability to make healthy choices.
“It’s time to ditch the idea individuals are responsible for their choices, and bad lifestyle choices lead to bad health.
“There’s an illusion of choice if you’re surrounded by an environment that makes it almost impossible to make healthy lifestyle choices.”
Rather than blaming individuals for making unhealthy choices, change is needed at a political and social level, Ma’u says.
Higher taxes on alcohol, tobacco, sugary drinks and foods that are high in salt or sugar could make a big difference to dementia rates, he says.
Poverty is also a barrier to accessing health services, making it harder for people to get early diagnosis and treatment for conditions that contribute to dementia, and for dementia itself, he says.
Cheaper GP visits and culturally appropriate services for older people could also help bring down dementia rates.
“If we reduced poverty in the population, many risk factors would reduce as well.”
The number of people with dementia in New Zealand is projected to double from 83,000 in 2025 to almost 170,000 by 2050, he says.
The Pacific population in New Zealand is comparatively young, so dementia rates are expected to soar in this group.
The costs of healthcare for dementia are expected to rise from $3 billion in 2025 to $5.9 billion by 2050.
“The only feasible way to reduce these costs is to prevent dementia from occurring.
“If we channel resources into the areas that need it most, that would most effectively reduce dementia risk across New Zealand,” says Ma’u.
