Dementia cases are on the rise around the world. In 2021, 57 million people were living with one of the neurodegenerative diseases under the dementia umbrella, and by 2050, that number is expected to reach 153 million.
But a new study suggests the tides may be turning, with younger generations facing lower risks for the disease as they age.
The research team, led by economist Xiaoxue Dou from the University of Queensland in Australia, ran a cross-sectional observational study using health survey data from the US, Europe and England: one that's representative of cross-sections of the populations involved at a single point in time, and based on observational data.
The researchers only used variables that were available across all the survey data to estimate participants' dementia status, to compensate for any missing observations.
"Birth cohorts born more recently were less likely to develop dementia in all three regions, albeit at different rates," the authors state in a journal article. "This decreasing trend was more pronounced among women than men."
They particularly focused on people aged 71 years or older, with the data sorted into age groups spanning four years. Compared with the older groups, younger cohorts had lower age-specific dementia prevalence rates: 21.2 percent for those in the US study; 38.9 percent in the European study; and 28.3 percent in England.
"For example, in the US, among people aged 81 to 85, 25.1 percent of those born between 1890-1913 had dementia, compared to 15.5 percent of those born between 1939-1943," economist and co-author Sabrina Lenzen of the University of Queensland told Nicola Davis at The Guardian.
The team cautions their data may not accurately reflect what is happening in minority groups. But the findings suggest that, while aging populations globally will probably mean greater numbers of people living with dementia, the percentage of people affected may actually be decreasing, at least among the groups studied.
This generational decrease in dementia risk, the study's authors write, "has important implications for health care planning, long-term care policies, and workforce requirements in aging populations."
This research was published in JAMA Network Open.