Dementia cases to double by 2050 — women carry two-thirds of Australia's burden

New research published in JAMA Neurology projects that the annual number of new dementia diagnoses globally will almost double — from 11.4 million in 2023 to 24.7 million by 2050. The study, led by researchers at the Centre for Healthy Brain Ageing (CHeBA) at UNSW Sydney, analysed data from 38,418 participants across 18 countries and territories and is described as one of the most comprehensive assessments of dementia incidence rates to date.

For Australians, the numbers carry weight. Nearly two-thirds of all dementia diagnoses in this country occur in women. That is not a rounding error; it is a pattern that is now prompting researchers to ask questions that go beyond the stock explanation.

Why women, specifically

The standard answer has always been longevity: women outlive men, and age is the dominant risk factor for dementia. This is true, and it accounts for a real portion of the gap. But CHeBA co-director Professor Henry Brodaty told ABC Health that the researchers suspect additional contributors are at work.

Menopause and the resulting decline in oestrogen production is one hypothesis under investigation. Oestrogen has been proposed as neuroprotective — but the evidence is mixed. Studies on hormone replacement therapy (HRT) and dementia risk have produced inconsistent results, and the relationship is not established. Prof Brodaty was candid: “Perhaps stopping oestrogen production may play a role but it’s not established.”

Historically lower rates of education and career complexity among women are also implicated. People who spend their working lives in cognitively demanding roles — particularly those involving managing others — appear to develop greater cognitive reserve, the brain’s resilience against the structural changes of dementia. Women, who for decades had less access to those roles, may have had fewer opportunities to build that reserve. Brodaty noted that cognitive reserve can be built across a lifetime, not only in childhood or early education — a point that matters for how we think about midlife.

Higher rates of depression, obesity, and low physical activity among women also appear in the analysis as possible contributors. Depression in particular has a well-documented association with dementia risk, and it remains undertreated in women at midlife.

Both sides of a difficult picture

The both-and here is uncomfortable but important. On one hand, the projected rise in dementia cases is not a fixed fate — an associated analysis estimates that addressing 14 modifiable risk factors could delay or prevent close to half of all dementia cases globally. Physical inactivity, hypertension, depression, hearing loss, smoking, diabetes, obesity, and social isolation all appear on that list. These are factors that are, to varying degrees, addressable in general practice and in daily life.

On the other hand, the tools available to treat established dementia in Australia remain limited. The newer disease-modifying therapies — monoclonal antibodies that target amyloid — have been approved in some countries but are not currently subsidised through the Pharmaceutical Benefits Scheme in Australia. As Dr Matthew Pase from Monash University told ABC Health, the projected burden is coming: “It is scary.” The implication is that prevention is not a soft alternative to treatment — in Australia’s current landscape, it is the main lever.

The menopause question — where the science actually sits

For women in their 40s and 50s, the menopause angle will catch the eye. The honest position is that it remains a research question, not a clinical directive. The hypothesis that oestrogen loss contributes to dementia risk is biologically plausible and actively investigated. But the evidence from HRT trials has been mixed: some studies suggest a window of benefit for women who start HRT near the onset of menopause, while others have shown no benefit or harm depending on the formulation, timing, and individual profile.

This is not a reason to dismiss the question — it is a reason to hold it with appropriate nuance. If you are weighing HRT decisions for other reasons (vasomotor symptoms, bone protection, quality of life), dementia prevention is a reasonable topic to raise with your GP. It should not be the primary driver of the decision given the current evidence, but it is not irrelevant either.

2 cents

The most immediately actionable item from this research is not about a medication — it is about the age 45–49 health assessment. The Medicare-subsidised check (MBS item 717) covers cardiovascular risk, diabetes screening, mental health, and is an opportunity to have a structured brain health conversation before the risk window narrows. If you are a woman in your 40s and have not had this assessment, it is worth booking.

Beyond that: the modifiable risk factors identified in this research — physical activity, social connection, blood pressure management, hearing health, depression treatment — are the same ones that appear across virtually every major preventive health framework. Addressing them does not require certainty about the dementia mechanism. It just requires starting.

Verdict: yes — this is one of the most significant public health projections of the year, and the women’s health angle is substantially under-discussed in Australian media.

---

Sources cited

1. Hormone changes could cause higher dementia rates among women — ABC Health, 13 October 2026
2. JAMA Neurology — Centre for Healthy Brain Ageing UNSW
3. Centre for Healthy Brain Ageing (CHeBA) — UNSW Sydney
4. RACGP — 45-49 year old patient health check (MBS item 717)