Annual Incidence of Dementia in US Will Double by 2060, Reaching 1 Million Cases
Annual incidence of dementia will double in White adults and triple among Black adults. The updated estimates place the lifetime risk of developing dementia after age 55 at 42%.
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The number of US adults who will develop dementia is expected to rise to 1 million per year by 2060, with Black individuals, women, and apolipoprotein E (APOE4) carriers expected to be most affected, according to new data published in Nature Medicine. Lifetime risk for the 3 highest-risk populations is projected to range from 44% to 59%, according to the findings. The estimated 1 million is approximately double the 514 000 annual cases recorded in 2020.1
Study authors, led by senior investigator Josef Coresh, MD, PhD, founding director of the Optimal Aging Institute and professor of population health and medicine at NYU Grossman School of Medicine, in New York, reported that the elevated risk of developing dementia at any time after age 55 years for US adults is 42%, which is more than double the risk reported in older studies.
Risk increases notably with age, said Coresh and colleagues, beginning at 4% between ages 55 to 75, rising to 20% by age 85, and then doubling to 42% by age 95, placing half the risk among the very old, over age 85 years.
Their results, the authors said, “highlight the urgent need for policies that enhance healthy aging, with a focus on health equity.”1
The previous underestimate of risk is attributable to gaps in record keeping and reporting, Coresh and colleagues emphasize, including unreliable documentation, minimal surveillance of early-stage cases of dementia, and the underreporting of cases among racial minority groups, which are disproportionately vulnerable. They refer to the Framingham Heart Study (FHS), frequently cited for its longitudinal health data, as an example of the latter deficiency. Framingham estimates that 11% to 14% of men and 19% to 23% of women will develop dementia in a lifetime, far less than the 42% Coresh et al report. The FHS population, however, is predominantly White, relatively affluent, and well educated. The study was also limited in the ability to identify cases of dementia, authors added.1
For a more accurate analysis of dementia risk, Coresh and colleagues tapped a far more diverse cohort and employed more sophisticated methodology and statistical analyses.
Study Cohort, Methods, Findings
The research team drew data from 1987 to 2020 from 15 043 participants in the community-based, longitudinal, prospective Atherosclerosis Risk in Communities Neurocognitive study. The cohort was 55.1% women and 26.9% were Black adults. Just under one-third (30.8%) of participants had at least one APOE4 allele, according to the study. All participants were free of dementia at age 55 years and were followed over a median of 23 years.1
The researchers estimated the lifetime risk for dementia for each patient from age 55 to 95 years, with mortality treated as a competing event. They applied lifetime risk estimates to US Census projections to approximate the annual number of incident dementia cases from 2020 to 2060, according to the study.
Over the median 23-year follow-up, there were 3252 incident cases of dementia. Coresh et al reported lifetime risk for dementia across specific populations was:
- 44% in Black adults vs 41% in White adults individuals, with the difference emerging at about age 75 years;
- 48% in women vs 35% in men — which is higher than current estimates from the Framingham Heart Study (23% vs. 14%) and the Rotterdam Study (31% vs. 19%) — with the difference emerging around age 85 years and perhaps related to women’s greater life expectancy, authors wrote; and
- 59% (95% CI, 53-65) in individuals with two APOE4 allele copies vs 48% (95% CI, 45-50) in those with one copy and 39% (95% CI, 37-40) in noncarriers, with the separation beginning at approximately 70 years
The number of individuals who will develop dementia each year is expected to nearly double among White individuals and triple among their Black counterparts, according to the study.1
Among the study’s limitations the authors acknowledge that some cases of dementia may have been erroneously classified while others may have been unaccounted for. The investigators also point out that the study was not subject to external validation and called for future population-based studies“ with long follow-up and comprehensive dementia ascertainment to validate lifetime risk estimates.”
“The pending population boom in dementia cases poses significant challenges for health policymakers in particular, who must refocus their efforts on strategies to minimize the severity of dementia cases, as well as plans to provide more healthcare services for those with dementia,” said Coresh in an NYU press release.2 Coresh also stressed the need for policies that increase efforts in Black communities to improve childhood education and nutrition, which he says previous research has shown to be beneficial in staving off cognitive decline later in life.
