18 Dec 2024

Poor physical health, difficulty with daily routines, and low scores on tests of thinking, memory, and information processing most strongly predict dementia later in life, according to a new report by the RAND Corporation, a nonprofit research organization funded by private and government sources. A trio of studies, sponsored by Genentech and conducted by RAND Social and Economic Well-Being, identified key predictors of dementia risk, addressed the benefits of detecting cognitive impairment early—including better planning for future care—and identified barriers to routine cognitive screening in older adults, such as cost and limited access to effective disease-modifying treatments.

“These interesting studies end with excellent recommendations. There is much that individuals can do to decrease the chance of dementia, and this is a cause for optimism and hope,” said Gill Livingston, University College London, the senior author of the Lancet Commission on Dementia. The reports’ findings align with established research, including those from the commission (Livingston et al., 2024; Aug 2017 conference news; Aug 2020 conference news).

High cost emerged as the greatest impediment to people seeking cognitive testing. One study, led by Susann Rohwedder, used data from the RAND American Life Panel—an internet survey of 1,439 individuals aged 50–70—to explore participants' likelihood of taking a cognitive test, visiting a specialist for follow-ups, or taking a disease-modifying treatment. While 80 percent of respondents said they would take a free cognitive assessment, only 40 percent said yes when the hypothetical cost was $300. Treatment effectiveness also influenced decisions: With access to a modestly effective treatment, the likelihood of someone agreeing to testing inched up from 55 percent to 60 percent, or 66 percent if that treatment was guaranteed to have no side effects. Financial concerns—such as higher long-term care insurance costs following a positive test result—also acted as a deterrent. Rohwedder and colleagues suggested implementing stronger confidentiality protections to reassure patients that their results would be kept private.

Sixty percent said they would take a disease-modifying treatment if it provided three additional years of independence, compared to 45 percent for a treatment offering six months. These numbers varied slightly by demographics. Wealthier or more educated people were more likely to seek testing and treatment.

The RAND economists recommended making cognitive testing free of charge to increase participation and adding it to regular medical checkups or providing financial support to broaden access. Yearly cognitive checkups have been covered by Medicare since 2011 as part of the annual wellness visit mandated by the Affordable Care Act, but not all doctors incorporate them (Mar 2019 news). Alzheimer’s blood tests on the horizon might also shift attitudes toward dementia screening (Nov 2024 conference news).

In another paper, Rand’s Peter Hudomiet and colleagues analyzed data from the Health and Retirement Study, a nationally representative survey that has tracked more than 20,000 U.S. volunteers, aged 50 and older, since 1992. The economists correlated incident dementia with 181 potential risk factors, including demographics, socioeconomic status, lifestyle, self-reported and physical measures of health, family history, their polygenic risk scores, and cognitive abilities. They identified characteristics of 60-year-olds that best predicted the onset of dementia 20 years later.

Of all potential risk factors, baseline cognitive ability as judged by memory and executive function tests, physical health, and difficulty with daily function topped the list. Other factors that correlated with increased risk for dementia included lack of regular exercise, diabetes, obesity, little interest in hobbies, lack of private health insurance, and either excessive alcohol consumption or never drinking alcohol.

“The results of this study can be used to improve dementia prediction and prevention efforts,” the authors claim. According to the authors, identifying people at high risk would allow resources to be directed toward them, encouraging advance planning for future care needs and promoting a lifestyle that supports brain health.

Not all experts agree. Andrew Budson, Boston University, does not believe that never drinking alcohol can increase dementia risk. “The current understanding is that those who begin to become impaired or ill often stop drinking,” he said. This has become known as the “healthy drinker” phenomenon. Other studies have debunked the idea that consuming no alcohol is bad for one’s health, since that conclusion was based on controls who had given up drinking because of prior excess (Biddinger et al., 2022; Daviet et al., 2022).

For a third RAND paper, first author Michael Hurd and colleagues examined how individuals, and their families, respond to cognitive decline or to receiving a diagnosis of some form of dementia. Many took steps to prepare for the future, such as establishing living wills, assigning a power of attorney, and downsizing. One in four respondents who received a formal diagnosis of dementia from a doctor reported asking their children for help managing their finances, versus only 2 percent of those who had received no formal diagnosis.

“The rapid developments in medical research on Alzheimer’s disease and related dementias in terms of testing and treatment options will lead to increased benefits from early testing,” the authors noted. “This report can provide guidance about which testing regimens would be most effective in increasing testing in the population overall and how to promote equitable access to dementia care.”—George R. Heaton.

George Heaton is a freelance writer in Durham, North Carolina.

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References

News Citations

1. Lancet Commission Claims a Third of Dementia Cases Are Preventable 11 Aug 2017
2. Lancet Commission’s Dementia Hit List Adds Alcohol, Pollution, TBI 4 Aug 2020
3. Alzheimer’s Association Report Argues for Cognitive Screening 8 Mar 2019
4. Some Alzheimer’s Blood Tests Are Racing Toward IVD Certification 21 Nov 2024
5. Similar Risk Factors Found for Young- and Late-Onset Dementia 5 Jan 2024

Paper Citations

1. Livingston G, Huntley J, Liu KY, Costafreda SG, Selbæk G, Alladi S, Ames D, Banerjee S, Burns A, Brayne C, Fox NC, Ferri CP, Gitlin LN, Howard R, Kales HC, Kivimäki M, Larson EB, Nakasujja N, Rockwood K, Samus Q, Shirai K, Singh-Manoux A, Schneider LS, Walsh S, Yao Y, Sommerlad A, Mukadam N. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet. 2024 Aug 10;404(10452):572-628. Epub 2024 Jul 31 PubMed.
2. Biddinger KJ, Emdin CA, Haas ME, Wang M, Hindy G, Ellinor PT, Kathiresan S, Khera AV, Aragam KG. Association of Habitual Alcohol Intake With Risk of Cardiovascular Disease. JAMA Netw Open. 2022 Mar 1;5(3):e223849. PubMed.

Further Reading

Papers

1. Hudomiet P, Hurd MD, Liu JL, Rohwedder S, Baker L, Chen A, Wang J, Girosi F. Improving the Detection of Cognitive Impairment and the Pathway to Treatment. Rand Corp., December 3, 2024 Rand Corporation