New dementia diagnoses worldwide could climb to 24.7 million a year by 2050 — more than double the roughly 11.4 million estimated in 2023 — according to an international study published October 12 in the journal JAMA Neurology and reported by BBC.
The research pooled data from more than 38,000 people across 22 studies covering 18 countries and territories on six continents. Researchers arrived at the projection by applying current age- and sex-specific incidence rates to expected population numbers in 2050, assuming those rates stay unchanged.
The figures refer to new cases each year, not the total number of people living with dementia or those who will actually receive a diagnosis.
The study also found that women develop dementia at a higher rate than men, even after accounting for age differences. The estimated rate was about 10.6 new cases per 1,000 women per year, compared with 8.6 per 1,000 men.
Why it matters
Dementia affects memory, thinking, and the ability to carry out daily activities. It results from diseases or injuries that damage the brain. Alzheimer's disease is the most common form, accounting for roughly 60 to 70 percent of cases, according to BBC. Other types include vascular dementia, caused by disrupted blood flow to the brain and sometimes occurring after a stroke, and Lewy body dementia, linked to abnormal protein deposits inside nerve cells.
While dementia is more common in older adults, it is not an inevitable part of aging and involves more than forgetfulness. It can also affect communication, decision-making, and behavior, and as it progresses, people need increasing help with everyday life.
The projected rise matters because it points to growing pressure on health systems, families, and caregivers — and because women sit on both sides of that pressure. They face a higher risk of developing the condition and provide the majority of care for those who have it.
What drives the gender gap
Longer life expectancy explains part of the difference. Women tend to live longer than men on average, making it more likely they reach the ages when dementia becomes more common. But the gap persists after age is taken into account, which means other factors are likely at work.
Researchers are examining a mix of health, social, economic, educational, and environmental influences, though sorting out the role of each will require more study. Education and mentally stimulating activities help build what is known as "cognitive reserve" — the brain's capacity to cope with damage before symptoms appear. In some communities, older generations of women had fewer opportunities for education and mentally engaging work than men of the same age. That may explain part of the disparity, but it is not a proven cause of the gap the new study identified, and women's circumstances vary across countries and generations.
Scientists are also investigating possible biological factors behind differences in Alzheimer's risk between women and men, including hormones and certain genetic factors. Some research focuses on how estrogen levels change during menopause and on whether specific gene variants tied to Alzheimer's affect the sexes differently. That question remains unresolved. The higher incidence in women cannot be reduced to menopause, nor does menopause cause dementia. Randomized trials have not shown that hormone therapy prevents dementia. Researchers also stress the importance of distinguishing findings specific to Alzheimer's from conclusions about dementia overall.
Caregiving falls mainly on women
Women provide about 70 percent of care hours for people living with dementia globally, according to the World Health Organization, as cited by BBC. As the condition advances, care may involve helping with bathing, dressing, and eating, along with constant supervision.
The consequences go beyond time and effort. The WHO notes that dementia also leaves psychological, social, and economic effects on caregivers themselves. A rising number of cases could therefore increase pressure on women in two ways: through the illness itself and through the responsibilities of looking after others.
Some risk factors can be addressed to lower the chances of developing dementia, including high blood pressure, diabetes, smoking, physical inactivity, social isolation, and hearing loss. Reducing these risks does not guarantee that no one will develop the condition.
What researchers say is needed
The study authors say the new projections call for investment in prevention, diagnosis, treatment, and care, particularly in low- and middle-income countries. The research found higher incidence rates in those settings, which are aging quickly and often have fewer resources, according to the researchers.
For women, the response requires looking at their position on both sides of care: as people who may need it and as the people who provide most of it.
Watch for follow-up research on the biological and social drivers behind the gender difference, and for how health systems in rapidly aging, lower-resource countries respond to the projected rise in cases.
