When asking if dementia rates are increasing, it is important to first consider population ageing.
Dementia rates in older people are falling. However, an ageing population means the sheer quantity of older people has grown.
The rate of people aged 70 and over with dementia has decreased between 1% and 2.5% per year from 2011 to 2023. [1]
In 1960, there were under 4 million people aged 65 and over. By 2060, that figure is expected to more than triple to over 12 million people – nearly 1 in 4 Americans. [2]
From 2030, older Americans will represent 21% of the population, up from 15% today. People over the age of 65 are projected to outnumber children under 18 for the first time in US history by 2034. [2]
Despite falling dementia rates, the total number of people with dementia is forecast to rise, because of the increasing population of older adults. [2]
Research shows that over 7 million people over the age of 65 had dementia in 2020. Current trajectories indicate that over 9 million US citizens could have dementia by 2030 and almost 12 million by 2040. [1]
Why are dementia rates falling?
Research shows that falling dementia rates in North America and Europe are likely to be driven by changes in lifestyle. Stark declines in smoking rates in men, a key risk factor for dementia, is a notable trend that may have impacted falling dementia rates. [3]
Incidentally, declines in the dementia rate are more pronounced in men than in women [3].
Other steps people can take to ward off dementia and keep our brains healthy include maintaining a healthy blood pressure, drinking within recommended limits, staying mentally and physically active, tempering cholesterol intake, and eating a balanced, nutritious diet. [3]
National Institute of Health 2016 study on falling dementia rates
A landmark NIH study conducted in 2016 found that there had been a progressive, decades long decline in dementia experience among older people in Framingham, Massachusetts.
Researchers assessed the cognitive capabilities of 5205 volunteers aged 60 and over every 5 years during four periods in the 1970s, 1980s, 1990s and 2000s. [4]
Their findings included:
- A correlation between education and dementia risk. Among volunteers with a high school diploma, dementia incidence declined by 22% in the 1980s, 38% in the 1990s, and 44% by the 2000s when compared to the dementia rate in the 1970s.
- Dementia incidence across all volunteers decreased by an average of 20% across the entire period of study.
- Average age of dementia diagnosis rose from 80 in the 1970s – to 85 in the 1980s.
- Vascular risk factors (excluding obesity and diabetes) showed a parallel decline over the course of the study, which may have contributed to falling dementia rates.
- Dementia cases related to stroke, atrial fibrillation or heart failure decreased over the course of the study.
Whilst these factors indicate healthier lifestyle changes and education may positively impact the rate of dementia incidence, they are not necessarily conclusive, and further research is needed. [4]
- Fact Sheet: U.S. Dementia Trends. (n.d.). PRB. https://www.prb.org/resources/fact-sheet-u-s-dementia-trends/#:~:text=Estimates%20vary%2C%20but%20experts%20report,nearly%2012%20million%20by%202040.
- Nasser, H. E. (2021, October 9). The U.S. Joins Other Countries With Large Aging Populations. Census.gov. https://www.census.gov/library/stories/2018/03/graying-america.html#:~:text=By%202060%2C%20nearly%20one%20in,caregiving%20and%20assisted%20living%20facilities.
- Pinches, E. (2020, August 4). Dementia rates falling by 13% per decade over last 30 years. Alzheimer’s Research UK. https://www.alzheimersresearchuk.org/dementia-rates-falling-13-decade/
- Satizabal, C. L., Beiser, A. S., Chouraki, V., Chêne, G., Dufouil, C., & Seshadri, S. (2016). Incidence of Dementia over Three Decades in the Framingham Heart Study. The New England journal of medicine, 374(6), 523–532. https://doi.org/10.1056/NEJMoa1504327
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